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Fused pentagon carbon network: A new anode material for Li ion batteries
Journal Pre-proofs Research paper Fused pentagon carbon network: a new anode material for Li ion batteries Tiantian Zeng, Qianxing Chen, Jinghua Guo, Hongbo Wang PII: DOI: Reference:
S0009-2614(20)30140-8 https://doi.org/10.1016/j.cplett.2020.137225 CPLETT 137225
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Chemical Physics Letters
Received Date: Revised Date: Accepted Date:
6 December 2019 12 February 2020 13 February 2020
Please cite this article as: T. Zeng, Q. Chen, J. Guo, H. Wang, Fused pentagon carbon network: a new anode material for Li ion batteries, Chemical Physics Letters (2020), doi: https://doi.org/10.1016/j.cplett.2020.137225
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Fused pentagon carbon network: a new anode material for Li ion batteries Tiantian Zeng†, Qianxing Chen†, Jinghua Guo, and Hongbo Wang* Laboratory of Advanced Materials Physical and Technology, University of Jinan, Jinan, Shandong 250022, China Abstract Based on the density functional theory (DFT), we study the fused pentagon carbon network as the anode materials. The theoretical results show that the carbon material has high lithium storage capacities, which can reach 637.8 mAh/g (LiC3.5) and 1116.2 mAh/g (LiC2) for the single side adsorptions and double sides adsorptions, respectively. It shows a metallic property with a high carrier velocity. For diffusion barriers in the anode, the energy barriers are below 0.25 eV, leading a high lithium mobility. These attractive theoretical results demonstrate that fused pentagon network is a promising anode material in lithium-ion batteries.
Key words: Li ion batteries; fused pentagon carbon network; anode materials; first-principle calculations
______________ †T.
Zeng and Q. Chen contributed equally to this work.
*Electronic
mail: [email protected]
1. Introduction Due to the fast growing demand for clean energy, lithium battery technology has developed rapidly in the past decade [1]. One of critical factors for the operation of Li ion batteries (LIBs) is electrode material. In the charging process, the cathode materials would donate electrons to the anode materials, meanwhile the Li ions from the cathode can be embedded into anode materials. In the case, the anode materials are required that they must have a high Li storage capacity. For the anode materials, the allotropes of carbon can be studied normally. For example, the graphite has been widely used in lithium ion battery because it is inexpensive and available [2-4]. Graphite provides a small voltage range, high Coulomb efficiency and 372 mAh/g lithium capacity for lithium-ion batteries [57]. However, the practical reversible capacity is about 350 mAh/g, which would have a limit. The pristine graphene will give a large energy barrier for Li atom penetration, due to the lack of effective diffusion holes. So the adverse conditions may limit the usage of graphene in the Li ion batteries. In addition, the mechanical stability and conductivity of electrode materials can also be required in the practical operation. However, these traditional materials may take some serious issues like low Li kinetics and Li capacities because of the geometric and electronic properties [8-12]. So many scientists are exploring the ideal anode carbon materials to realize the excellent performance of LIBs. Then many graphene–based composites have been developed, including few-layer graphene, reduced graphene oxide, doping graphene, functionalized graphene and heterostructure. They show the superior Li capacity [13-20], such as 4 layer graphene thickness (1264 mAh/g), the holey graphene (889 mAh/g), S-doped graphene (1400 mAh/g), N-doped graphene (1043 mAh/g) and CoS2/graphene (885 mAh/g) [13-18]. Meanwhile, the 2D large porous carbon materials also provide a rational route for designing high-performance carbon bashed LIB anode materials. For instance, the 2D graphdiyne is synthesized on experiment in 2010 [21]. As anode materials, the 2D graphdiyne has been confirmed with a high-efficiency on theoretical and experimental studies [22]. A wealth of carbon allotropes
have been theoretically predicted as the superior LIB anode materials, like ψ-graphene, biphenylene, phagraphene, popgraphene, xgraphene and graphenylene [23-29]. With the development of technologies, it is necessary and possible to explore new anode materials. The basic demands for the target material: (1) light mass and low areal density [9,30] (2) the higher lithium capacity and lower diffusion barrier [9,10,31] (3) the higher Li passing rate and impermeable of electrolytes. Based on these conditions, we suggest that the theoretically predicted sp2 fused pentagon network is suitable for our aim [32]. By the ab initio molecular dynamics (AIMD), we find that it can be synthesized from the acepentalene structure sharing three edges with three adjacent pentagon trimmers [32], and the approach has been successfully employed in the synthesis of graphene sheet, and nanoribbons as well as some other nanostructures [33-38]. According to our detailed first principle calculations, the pentagon network was confirmed to be stable. Meanwhile, there are uniform pentagon and dodecagon pores for the adsorptions and diffusion of the Li atoms as an electrode material. From these conditions, fused pentagon carbon network is expected to satisfy the requirements of anode materials. In this paper, by using first-principle calculations based on the density functional theory (DFT), we have explored the diffusion efficiency and storage capacity of lithium in the fused pentagon carbon network. Both monolayer and bilayer systems are considered in our calculations. The penetration of the lithium ion and molecules from electrolyte are studied by the nudge elastic band (NEB) method. What’s more, the electronic properties, carrier velocity and open-circuit voltage are also calculated. High lithium capacity, low diffusion barrier, and electronic properties provide excellent conditions for fused pentagon network to become the anode material. 2. Methods Our first-principles calculations were performed within the framework of density functional theory (DFT), with a plane wave basis set as implemented in the Vienna ab initio simulation package
(VASP) [39,40]. The projector augmented wave (PAW) method was used. The cutoff energy for the plane-wave basis was set to 500 eV. The exchange and correlation energies are described by using a generalized gradient approximation (GGA) and Perdew, Burke, and Ernzerhof (PBE) parameterization [40,41]. The fused pentagon network sheet was placed in the xy plane of the supercell with a 16 Å vacuum in the z lattice, which is large enough to ignore the effects from neighboring images. The sampling k points in the first Brillouin zone was set to be 15×15×1 to integrate the electronic properties [42]. All the atoms here were fully relaxed until the force and energy were converged to 0.01 eV/Å and 10-6 eV. The phonon calculation was performed by using the Phonopy code with the finite displacement method [43,44], interfaced with the density functional perturbation theory as implemented in VASP. In phonon calculation, the cutoff energy was set to 500 eV, accompanied by more stringent convergence criteria for energy (10-7eV) and force (0.1 meV/Å). Ab initio molecular dynamics (AIMD) simulations were performed to estimate the stability. The temperature was maintained constant using a Nose´-Hoover method. The lithium diffusion barrier was calculated by the nudge elastic band (NEB) algorithm [45]. Van der Waals correction (vdW-D3) was considered in the calculation [46]. 3. Results and discussion The structure of fused pentagon carbon network is shown in Fig. 1(a). The optimal lattice constants are a=b=7.14 Å, which are in good agreement with previous predictions [32,47]. There are three chemically inequivalent carbon atoms in one unit cell, which are marked by the different colors. These carbon atoms would form the C-C bonds with a sp2 hybridization with three neighboring carbon atoms, giving a uniform pentagon and twelve-sided rings. In the Fig. 1(b), we give the stability diagram of the carbon allotropes. We can find that the energy per atom of the fused pentagon network is lower than that of the experimentally synthesized graphdiyne while it is higher than that of graphene. For the
carbon density, fused pentagon network is lower than graphene, and higher than graphdiyne. From this energy-based ordering, we assume that the metastable fused pentagon networks can be synthesized experimentally. Considered from the energies per atom and carbon areal density, the fused pentagon carbon network likely to be synthesized. Moreover, we calculate the phonon spectrum and molecular dynamics of fused pentagon carbon network. In the Fig. 1(c), there is no imaginary mode in the whole Brillouin zone, suggesting the dynamic stability with small atomic displacements. We also carefully carry on ab initio molecular dynamics (AIMD) simulation in Fig. 1(d). After the AIMD simulation for 10 ps, the structure at the end simulations has a slight distortion, which informed that the planar structure can retain its stable configuration at 1000 K. After the relaxation, it can back to the original configuration quickly. In addition, we also calculate the cleavage energy about 0.23 J/m2, being well comparable with other vdW bonded materials of great interest: 0.43 J/m2 has been calculated for graphite, 0.27 J/m2 for MoS2 and 0.30 J/m2 for CrI3 [48,49]. These results suggest that this carbon material is quite stable. We calculate the electronic properties of the fused pentagon carbon network. The calculated energy band structures and the DOS are presented in Fig. 2(a). There is no gap between the valence and conduction bands, showing a metal characteristic. The charge carriers are evaluated to 8.3×105 m/s velocity agreeing with that of graphene [50]. Further, we can see that the orbitals around the Fermi level are mainly pz orbitals, which form the weak π bonding. For the s, px and py orbitals, they can hybridize together at a deep energy level, forming the strong σ bonds in the plane. Moreover, we calculate the electron localization function (ELF) for the bonding feature in Fig. 2(b). The values range of ELF is from 0.0 to 1.0. The value 0.0 refers to the lowest charge density, 0.5 and 1.0 indicate that the fully delocalized and localized electrons. ELF value between two neighboring C atoms is about 0.9, which represents a strong σ bonding states by the x, px and py orbitals in the deep levels. It confirms the covalent-like nature of C-C bonds in the fused pentagon network. The delocalized π
bonds are from the pz orbitals, giving rise to metallicity of the structure. Due to the excellent structural and electronical properties, the fused pentagon carbon network can be as the candidate anode material of the Li ion batteries. First, we should consider the adsorptions of Li atoms on the fused pentagon carbon network. We use a 2x2 supercell as substrate to avoid the interaction between Li adatoms. The absorption energy can be defined by formula: 𝐸𝑎𝑑𝑠 =
𝑛𝐸𝐿𝑖 + 𝐸𝑀 ― 𝐸𝐿𝑖𝑛𝑀 𝑛
𝐸𝐿𝑖𝑛𝑀 and 𝐸𝑀 are the total energies of fused pentagons network supercell with and without lithium atom adsorption, respectively. 𝐸Li is the energy per Li in the bulk Li metal. There are eight unequal possible sites to adsorb Li atom as shown in Fig. 3(a). The H1 and H2 are the hollow sites of the pentagonal and twelve-sided rings. The T1, T2 and T3 are the top sites of unequal carbon atoms. The B1, B2 and B3 are the bridge sites of different C-C bonds. Our results show that the H1 site is energetically most favorable, and the calculated adsorption energy is about -0.94 eV. The negative adsorption energies indicate that Li atoms will not cluster and preferably bind at the H1 site. For the hollow site of twelve-sided ring, the Li atom would not be located on the center ring due to a large diameter of the twelve-sided ring. It can connect with the neighboring carbon atoms forming few Li-C bonds and the adsorption energy is about -0.66 eV. For other adsorption sties, the adsorbed configurations are not stable, and the Li atom would move to the hollow site of pentagonal ring. For the LIBs, it is required that more Li ions can be adsorbed on the anode materials, getting a large storage capacity. Then we would put more lithium atoms on fused pentagonal network one by one, as shown in Fig. S1(a), until the adsorption energy per lithium atom has a positive value. Our results show that at least 16 lithium atoms are attached to the surface of monolayer 2x2 supercell, and the average adsorption energy was -0.24 eV per Li atom. Then there are no visible distortion in the fused pentagon carbon network. The theoretical capacity of the results was 637.8 mAh/g. If the Li atoms are adsorbed on two sides of the monolayer carbon materials, the number of Li atoms can reach
28 and the corresponding adsorption energy is -0.19 eV in Fig. S1(b). The theoretical capacity is 1116.2 mAh/g. Next, we define the average open-circuit voltage by 𝑂𝐶𝑉 ≈
𝐸𝐿𝑖𝑥1 𝐹𝑃𝑁 ― 𝐸𝐿𝑖𝑥2 𝐹𝑃𝑁 + (𝑥2 ― 𝑥1)𝜇𝐿𝑖 (𝑥2 ― 𝑥1)𝑒
Where 𝐸𝐿𝑖𝑥1 and 𝐸𝐿𝑖𝑥2 correspond to different Li loadings of the fused pentagon network. 𝐸𝐿𝑖𝑥1 𝐹𝑃𝑁 and 𝐸𝐿𝑖𝑥2 𝐹𝑃𝑁 are the total energies of these Lix1 and Lix2 adsorbed fused pentagon network sheets, respectively. 𝜇𝐿𝑖 is the chemical potential calculated as the energy per atom of Li bulk. For the detailed description for the intercalation process, the OCV curve was shown in Fig. S2. The OCV was declined with the Li loading on the fused pentagon network in the overall trend. From the fifth atom, it will be located on the other side of the fused pentagon network, and the adsorption energy has an increase, which is responsible for the increase of the fifth point in the Fig. S2. The average OCV calculated by averaging the voltage profile versus Li concentration is found to be 0.28 V for the fused pentagon carbon network, which is slightly higher than that of graphite (0.11 V), but much lower than that of 2D VS2 (0.93 V) [51], Mo2C (0.68 V) [52] , popgraphene (0.45 V) [53], and ψ-graphene (0.64 V) [23]. An important influencing factor for LIBs anode material is that the mobility of lithium ions on the fused pentagon carbon network. For the monolayer fused carbon materials, the pentagonal rings are the preferred adsorption sites of Li atoms, so the migration should occur between the pentagonal rings mainly. During the diffusion of Li adatoms on the surface, they need cross the bridge sites of C-C bonds. Looking the structure of the fused carbon network, we find that there are two unequal C-C bonds, including the C-C bond in the acepentalene molecule (marked by blue) and the shared C-C bond between the acepentalene molecules (marked by orange), as shown in Fig. 3(b). From its preferred adsorption site to the nearest-neighbor stable adsorption site, we consider two migration pathways of Li adatoms, crossing these two different C-C bridge sites, as shown by Path 1 and Path
2. For the study of diffusion migration pathways, we use the CI-NEB method, and the corresponding energy barriers are shown in Fig. 3(c). We can see that the diffusion energy barrier in acepentalene molecule is 0.23 eV from the Path 1. For crossing the C-C bonds shared by the molecule, the energy barrier is only 0.12 eV from Path 2. The energy barriers are lower than that of phagraphene (0.420.08eV) [26], popgraphene (0.36-0.3 eV) [27], graphite (0.4-0.218 eV) [54]. During practical applications, LIBs anode materials are usually used by stacking multiple layers, it is worth to study the interaction between the layers. In the paper, we consider five stacking configurations of bilayer. We test AA stacking configuration and four different AB stacking configurations, which are shown in Fig. S3. By the calculations, the AA stacking is the ground state configuration, which is more stable than these AB configurations by 2.1 meV, 2.7 meV, 2.9 meV and 4.2 meV per atom, respectively. The AA stacking has the lowest energy, which would be considered in the multilayers stacking. In addition, for the AA stacking, the phonon spectrum has no virtual frequency, and the molecular dynamics displays that structure can maintain the stability of the overall configuration within 300 K and 10 ps, indicating that the stability of the structure is reliable, shown in Fig. S4. In the practical charging and discharging process, the Li atoms would also diffuse between the layers. Following, we study the effects of the multilayer on the diffusion. First, we study the diffusion outer surface of bilayer. The Li atoms would move between the pentagonal rings, and the diffusion pathways are same with that in Fig. 3(b). As shown in Fig. 4(a), the corresponding calculated energy barriers are 0.22 eV and 0.14 eV. There are a light change due to the effect of other layer. For the diffusion in the interlayer interstitial in Fig. 4(b), the energy barriers are 0.17 eV and 0.10 eV, respectively. The diffusion is easier for the Li atoms in the interlayer. While in the practical working process, the Li atoms need to move different layers. As shown in Fig. 4(c), the Li atoms need to move the hollow site of twelve rings firstly, and then cross the large hole to reach the interlayer interstitial.
We can see that the energy barrier mainly arises from the energy costing of crossing the shared C-C bond between the pentagonal ring and dodecagon ring, about 0.25 eV. From the hollow site upper to the interlayer interstitial, the energy barrier is only 0.03 eV. Comparing all the energy barriers, the diffusions of Li atoms in the anode materials occur easily, which is beneficial for practical application. It indicates that there is a good charge-discharge ability for fused pentagon carbon network in the battery. Based on the discussion above, the dodecagon carbon rings of fused pentagon network could permit lithium atoms to penetrate the anode materials favorably. In the common organic electrolytes, these
molecules,
including
EC(C3H4O3),
PC(C5H7O6),
DEC(C5H10O3),
DMC(C3H6O3),
EMC(C4H8O3) [55], would be limited through the holes. In the paper, we study the possibility of EC molecule through the hole, which has the smallest size. We calculate the energy barrier through the hole by the NEB method in the Fig. 5(a). The energy barrier is about 11 eV, which is too large to cross the hole. The diameter of the hole is only 5.43 Å, and the distance between the EC molecule and the edge of the ring is about 1.5 Å with z=0 plane, which is in the range of bonding. As shown in Fig. 5(b), we give the electron density distributions with z=0, and there is a large overlap of electron densities between the EC molecule and the pore rim of dodecagon carbon ring, hindering the passing event of EC molecule. 4. Conclusion In summary, we study the possibility of fused pentagon carbon network as the anode materials via first-principles calculations. First, we give the phonon spectrum and AIMD calculation of the fused pentagon carbon network, confirming the dynamic stability. The carbon material shows a metallic behavior with a carrier velocity about 8.3×105 m/s, which is beneficial for the efficiency of Li ion batteries. For the adsorbed configurations, the Li atom prefers to be located on the pentagonal rings. When more Li atoms are adsorbed on single side or two sides of the monolayer sheet, the
capacities can reach 637.8 mAh/g (LiC3.5) and 1116.2 mAh/g (LiC2), respectively. For the diffusion, the maximum energy barrier arises from the interlayer penetration, only 0.25 eV, indicating that the Li atoms can move in the anode materials easily. Besides, the OCV is also calculated about 0.28 V. These attractive theoretical calculation results demonstrate that fused pentagon carbon network is a promising multifunctional material in lithium-ion batteries. Acknowledgments This work was supported by the National Natural Science Foundation of China (Grant No: 11704153), the Natural Science Foundation of Shandong Province (Grant No: ZR2017LA009), and the fund from University of Jinan (Grant No: XKY1707).
References [1] G. C. Guo, D. Wang, X. L. Wei, Q. Zhang, H. Liu, W. M. Lau, L. M. Liu, First-Principles Study of Phosphorene and Graphene Heterostructure as Anode Materials for Rechargeable Li Batteries, J. Phys. Chem. Lett. 6 (2015) 5002. [2] Y. S. Meng, M. E. Arroyo-de Dompablo, First principles computational materials design for energy storage materials in lithium ion batteries, Energy Environ. Sci. 2 (2009) 589. [3] J. M. Tarascon, M. Armand, Issues and challenges facing rechargeable lithium batteries, Nature 414 (2001) 359. [4] S.-H. Zhou, J. Zhang, Z.-Z. Ren, J.-F. Gu, Y.-R. Ren, S. Huang, W. Lin, Y. Li, Y.-F. Zhang, W.-K. Chen, First-principles study of MoSSe_graphene heterostructures as anode for Li-ion batteries, Chem. Phys. 529 (2020) 110583. [5] S. Goriparti, E. Miele, F. De Angelis, E. Di Fabrizio, R. Proietti Zaccaria, C. Capiglia, Review on recent progress of nanostructured anode materials for Li-ion batteries, J. Power Sources 257 (2014) 421. [6] G. Zhu, K. Lü, Q. Sun, Y. Kawazoe, P. Jena, Lithium-doped triazine-based graphitic C3N4 sheet for hydrogen storage at ambient temperature, Comput. Mater. Sci. 81 (2014) 275. [7] M. D. Bhatt, C. O'Dwyer, Recent progress in theoretical and computational investigations of Liion battery materials and electrolytes, Phys. Chem. Chem. Phys. 17 (2015) 4799. [8] W.-M. Zhang, J.-S. Hu, Y.-G. Guo, S.-F. Zheng, L.-S. Zhong, W.-G. Song, L.-J. Wan, Tin-
Nanoparticles Encapsulated in Elastic Hollow Carbon Spheres for High-Performance Anode Material in Lithium-Ion Batteries, Adv. Mater. 20 (2008) 1160. [9] H. Li, H. Zhou, Enhancing the performances of Li-ion batteries by carbon-coating: present and future, Chem. Commun. (Camb) 48 (2012) 1201. [10] X. Meng, X. Q. Yang, X. Sun, Emerging applications of atomic layer deposition for lithium-ion battery studies, Adv. Mater. 24 (2012) 3589. [11] J. Wang, X. Sun, Understanding and recent development of carbon coating on LiFePO4 cathode materials for lithium-ion batteries, Energy Environ. Sci. 5 (2012) 5163. [12] S. Xu, R. M. Jacobs, H. M. Nguyen, S. Hao, M. Mahanthappa, C. Wolverton, D. Morgan, Lithium transport through lithium-ion battery cathode coatings, J. Mater. Chem. A 3 (2015) 17248. [13] H. Chakraborti, S. K. Pal, Assessment of amine functionalized graphene nanoflakes for anode materials in Li-ion batteries: An ab initio study, Chem. Phys. Lett. 600 (2014) 118. [14] E. Yoo, J. Kim, E. Hosono, H.-S. Zhou, T. Kudo, I. Honma, Large Reversible Li Storage of Graphene Nanosheet Families for Use in Rechargeable Lithium Ion Batteries, Nano Lett. 8 (2008) 2277. [15] Z. Jiang, B. Pei, A. Manthiram, Randomly stacked holey graphene anodes for lithium ion batteries with enhanced electrochemical performance, J. Mater. Chem. A 1 (2013) 7775. [16] Y. Yan, Y.-X. Yin, S. Xin, Y.-G. Guo, L.-J. Wan, Ionothermal synthesis of sulfur-doped porous carbons hybridized with graphene as superior anode materials for lithium-ion batteries, Chem. Commun. 48 (2012) 10663. [17] X. Li, D. Geng, Y. Zhang, X. Meng, R. Li, X. Sun, Superior cycle stability of nitrogen-doped graphene nanosheets as anodes for lithium ion batteries, Electrochem. Commun. 13 (2011) 822. [18] G. Li, Y. Li, H. Liu, Y. Guo, Y. Li, D. Zhu, Architecture of graphdiyne nanoscale films, Chem. Commun. 46 (2010) 3256. [19] J. Zhang, Y. Zhou, G. Zheng, Q. Huang, X. Zheng, P. Liu, J. Zhang, X. Guan, Novel assembly and electrochemical properties of anatase TiO2-graphene aerogel 3D hybrids as lithium-ion battery anodes, Chem. Phys. Lett. 662 (2016) 214. [20] H. H. Tran, P. H. Nguyen, V. H. Cao, L. T. Nguyen, V. M. Tran, M. L. P. Le, S.-J. Kim, V. Vo, SnO2 nanosheets/graphite oxide/g-C3N4 composite as enhanced performance anode material for lithium ion batteries, Chem. Phys. Lett. 715 (2019) 284. [21] X. Zhu, Z. Meng, H. Ying, X. Xu, F. Xu, W. Han, A novel CoS2/reduced graphene oxide/multiwall carbon nanotubes composite as cathode for high performance lithium ion battery, Chem. Phys. Lett. 684 (2017) 191.
[22] C. Huang, S. Zhang, H. Liu, Y. Li, G. Cui, Y. Li, Graphdiyne for high capacity and long-life lithium storage, Nano Energy 11 (2015) 481. [23] X. Li, Q. Wang, P. Jena, ψ-Graphene: A New Metallic Allotrope of Planar Carbon with Potential Applications as Anode Materials for Lithium-Ion Batteries, J. Phys. Chem. Lett. 8 (2017) 3234. [24] D. Ferguson, D. J. Searles, M. Hankel, Biphenylene and Phagraphene as Lithium Ion Battery Anode Materials, ACS Appl. Mater. Interfaces 9 (2017) 20577. [25] F. Schlütter, T. Nishiuchi, V. Enkelmann, K. Müllen, Octafunctionalized biphenylenes: molecular precursors for isomeric graphene nanostructures, Angew. Chem. Int. Ed. 53 (2014) 1538. [26] Z. Wang, X. F. Zhou, X. Zhang, Q. Zhu, H. Dong, M. Zhao, A. R. Oganov, Phagraphene: A Low-Energy Graphene Allotrope Composed of 5-6-7 Carbon Rings with Distorted Dirac Cones, Nano Lett. 15 (2015) 6182. [27] S. Wang, B. Yang, H. Chen, E. Ruckenstein, Popgraphene: a new 2D planar carbon allotrope composed of 5-8-5 carbon rings for high-performance lithium-ion battery anodes from bottom-up programming, J. Mater. Chem. A, 6 (2018) 6815. [28] S. Wang, Y. Si, B. Yang, E. Ruckenstein, H. Chen, Two-Dimensional Carbon-Based Auxetic Materials for Broad-Spectrum Metal-Ion Battery Anodes, J. Phys. Chem. Lett. 10 (2019) 3269. [29] Y.-X. Yu, Graphenylene: a promising anode material for lithium ion batteries with high mobility and storage, J. Mater. Chem. A 1 (2013) 13559. [30] K. Min, S. W. Seo, B. Choi, K. Park, E. Cho, Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes, ACS Appl. Mater. Interfaces 9 (2017) 17822. [31] X. Xiao, P. Lu, D. Ahn, Ultrathin Multifunctional Oxide Coatings for Lithium Ion Batteries, Adv. Mater. 23 (2011) 3911. [32] M. Maruyama, S. Okada, Two-dimensional sp2 carbon networks of fused pentagon, Jpn. J. Appl. Phys. 53 (2014) 06JD02. [33] Z. Li, P. Wu, C. Wang, X. Fan, W. Zhang, X. Zhai, C. Zeng, Z. Li, J. Yang, J. Hou, LowTemperature Growth of Graphene by Chemical Vapor Deposition Using Solid and Liquid Carbon Sources, ACS Nano 5 (2011) 3385. [34] J. Cai, P. Ruffieux, R. Jaafar, M. Bieri, T. Braun, S. Blankenburg, M. Muoth, A. P. Seitsonen, M. Saleh, X. Feng, K. Mullen, R. Fasel, Atomically precise bottom-up fabrication of graphene nanoribbons, Nature 466 (2010) 470. [35] Y. C. Chen, D. G. de Oteyza, Z. Pedramrazi, C. Chen, F. R. Fischer, M. F. Crommie, Tuning the Band Gap of Graphene Nanoribbons Synthesized from Molecular Precursors, ACS Nano 7 (2013)
6123. [36] H. Chen, Y. Yang, Z. Hu, K. Huo, Y. Ma, Y. Chen, X. Wang, Y. Lu, Synergism of C5N SixMembered Ring and Vapor−Liquid−Solid Growth of CNx Nanotubes with Pyridine Precursor, J. Phys. Chem. B 110 (2006) 16422. [37] L. Grill, M. Dyer, L. Lafferentz, M. Persson, M. V. Peters, S. Hecht, Nano-architectures by covalent assembly of molecular building blocks, Nat. Nanotechnol. 2 (2007) 687. [38] S. Beniwal, J. Hooper, D. P. Miller, P. S. Costa, G. Chen, S.-Y. Liu, P. A. Dowben, E. C. H. Sykes, E. Zurek, A. Enders, Graphene-like Boron−Carbon−Nitrogen Monolayers, ACS Nano 11 (2017) 2486. [39] G. Kresse, J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54 (1996) 11169. [40] G. Kresse, D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method, Phys. Rev. B 59 (1999) 1758. [41] J. P. Perdew, K. Burke, M. Ernzerhof, Generalized Gradient Approximation Made Simple, Phys. Rev. Lett. 77 (1996) 3865. [42] H. J. Monkhorst, J. D. Pack, Special points for Brillouin-zone integrations, Phys. Rev. B 13 (1976) 5188. [43] K. Parlinski, Z. Q. Li, Y. Kawazoe, First-Principles Determination of the Soft Mode in Cubic ZrO2, Phys. Rev. Lett. 78 (1997) 4063. [44] A. Togo, I. Tanaka, First principles phonon calculations in materials science, Scr. Mater. 108 (2015) 1. [45] G. Henkelman, H. Jónsson, Improved tangent estimate in the nudged elastic band method for finding minimum energy paths and saddle points, J. Chem. Phys. 113 (2000) 9978. [46] S. Grimme, J. Antony, S. Ehrlich and H. Krieg, A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu, J. Chem. Phys., 132 (2010) 154104. [47] M. Maruyama, S. Okada, Two-Dimensional sp2 Carbon Network of Fused Pentagons: All Carbon Ferromagnetic Sheet, Appl. Phys. Express 6 (2013) 095101. [48] T. Björkman, A. Gulans, A. V. Krasheninnikov, R. M. Nieminen, van der Waals Bonding in Layered Compounds from Advanced Density-Functional First-Principles Calculations, Phys. Rev. Lett. 108 (2012) 235502. [49] M. A. McGuire, H. Dixit, V. R. Cooper, B. C. Sales, Coupling of Crystal Structure and Magnetism in the Layered, Ferromagnetic Insulator CrI3, Chem. Mater. 27 (2015) 612.
[50] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, M. I. Katsnelson, I. V. Grigorieva, S. V. Dubonos, A. A. Firsov, Two-dimensional gas of massless Dirac fermions in graphene, Nature 438 (2005) 197. [51] J. Yu, Z. Zhen, C. R. Cabrera, Z. Chen, Metallic VS2 Monolayer: A Promising 2D Anode Material for Lithium Ion Batteries, J. Phys. Chem. C 117 (2013) 25409. [52] D. Çakır, C. Sevik, O. Gülseren, F. M. Peeters, Mo2C as a high capacity anode material: a firstprinciples study, J. Mater. Chem. A 4 (2016) 6029. [53] S. Wang, B. Yang, H. Chen, E. Ruckenstein, Reconfiguring graphene for high-performance metal-ion battery anodes, Energy Storage Materials 16 (2019) 619. [54] J. Liu, S. Wang, Q. Sun, All-carbon-based porous topological semimetal for Li-ion battery anode material, Proc. Natl. Acad. Sci. U.S.A. 114 (2017) 651. [55] J. B. Goodenough, Y. Kim, Challenges for Rechargeable Li Batteries, Chem. Mater. 22 (2010) 587.
Fig. 1 (a) Structure of fused pentagon carbon network: concluding three types of unequal carbon atoms marked by blue, green and red, respectively. (b) Stability diagram of the common carbon allotropes. (c) Phonon spectrum of fused pentagon carbon network. (d) Evolution of potential energy per atom versus simulation time. The insets I and II are the initial and final structures of the simulations, respectively.
Fig. 2 (a) The orbital-resolved bandstructures of fused pentagon carbon network (left) and the DOS (right). (b) The calculated ELF which shows the covalent–like bonding nature in the fused pentagon carbon network.
Fig. 3 (a) Adsorption sites of Li atom on monolayer fused pentagon carbon network. (b)-(c) The possible migration paths and the corresponding diffusion barrier profiles of Li diffusion on fused pentagon carbon network.
Fig. 4 (a) and (b) The migration paths and the corresponding diffusion barriers of Li on the outer surface and in the interlayer interstitial of bilayer. (c) The permeability of Li atom among the different layers.
Fig. 5 (a) Potential energy profiles of EC molecule through the largest pore of fused pentagon carbon network. (b) The electron density distribution at an iso value of 0.05 Bohr/Å3 for the states where z=0 Å.
Fig. S1 (a) and (b) The structures of the maximum Li atoms adsorbed on the single side and double sides of monolayer fused carbon network, respectively. The atoms on the upper and lower surface are marked by green and yellow, respectively.
Fig. S2 The OCV curve, x corresponds to different Li loading of the fused pentagon network.
Fig. S3 (a) Configuration of AA stacking. (b)-(e) Four different configurations of AB stacking. The A and B layers are marked by gray and yellow, respectively. The AA stacking is the ground state. The below values are the relative energies per atom for these different AB configurations.
Fig. S4 (a) Phonon spectrum and (b) Evolution of potential energy per atom versus simulation time of AA stacking fused pentagon carbon network. Molecular dynamics simulation at 300K.
We study the fused pentagon network as the anode materials. The theoretical lithium storage capacities can reach 637.8 mAh/g and 1116.2 mAh/g for the single side adsorptions and double sides adsorptions, respectively. The diffusion barriers are below 0.25 eV, leading a high lithium mobility. It has the excellent metallic properties.
Dear editor, At the requirement, we are now listing the highlights of our paper as below for your convenience. (1) The fused pentagon carbon network has a high lithium storage capacity. (2) The Li atom has a low diffusion barrier. (3) The anode material has the excellent electronic properties. Yours sincerely, Hongbo Wang
S0009-2614(20)30140-8 https://doi.org/10.1016/j.cplett.2020.137225 CPLETT 137225
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Chemical Physics Letters
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Please cite this article as: T. Zeng, Q. Chen, J. Guo, H. Wang, Fused pentagon carbon network: a new anode material for Li ion batteries, Chemical Physics Letters (2020), doi: https://doi.org/10.1016/j.cplett.2020.137225
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Fused pentagon carbon network: a new anode material for Li ion batteries Tiantian Zeng†, Qianxing Chen†, Jinghua Guo, and Hongbo Wang* Laboratory of Advanced Materials Physical and Technology, University of Jinan, Jinan, Shandong 250022, China Abstract Based on the density functional theory (DFT), we study the fused pentagon carbon network as the anode materials. The theoretical results show that the carbon material has high lithium storage capacities, which can reach 637.8 mAh/g (LiC3.5) and 1116.2 mAh/g (LiC2) for the single side adsorptions and double sides adsorptions, respectively. It shows a metallic property with a high carrier velocity. For diffusion barriers in the anode, the energy barriers are below 0.25 eV, leading a high lithium mobility. These attractive theoretical results demonstrate that fused pentagon network is a promising anode material in lithium-ion batteries.
Key words: Li ion batteries; fused pentagon carbon network; anode materials; first-principle calculations
______________ †T.
Zeng and Q. Chen contributed equally to this work.
*Electronic
mail: [email protected]
1. Introduction Due to the fast growing demand for clean energy, lithium battery technology has developed rapidly in the past decade [1]. One of critical factors for the operation of Li ion batteries (LIBs) is electrode material. In the charging process, the cathode materials would donate electrons to the anode materials, meanwhile the Li ions from the cathode can be embedded into anode materials. In the case, the anode materials are required that they must have a high Li storage capacity. For the anode materials, the allotropes of carbon can be studied normally. For example, the graphite has been widely used in lithium ion battery because it is inexpensive and available [2-4]. Graphite provides a small voltage range, high Coulomb efficiency and 372 mAh/g lithium capacity for lithium-ion batteries [57]. However, the practical reversible capacity is about 350 mAh/g, which would have a limit. The pristine graphene will give a large energy barrier for Li atom penetration, due to the lack of effective diffusion holes. So the adverse conditions may limit the usage of graphene in the Li ion batteries. In addition, the mechanical stability and conductivity of electrode materials can also be required in the practical operation. However, these traditional materials may take some serious issues like low Li kinetics and Li capacities because of the geometric and electronic properties [8-12]. So many scientists are exploring the ideal anode carbon materials to realize the excellent performance of LIBs. Then many graphene–based composites have been developed, including few-layer graphene, reduced graphene oxide, doping graphene, functionalized graphene and heterostructure. They show the superior Li capacity [13-20], such as 4 layer graphene thickness (1264 mAh/g), the holey graphene (889 mAh/g), S-doped graphene (1400 mAh/g), N-doped graphene (1043 mAh/g) and CoS2/graphene (885 mAh/g) [13-18]. Meanwhile, the 2D large porous carbon materials also provide a rational route for designing high-performance carbon bashed LIB anode materials. For instance, the 2D graphdiyne is synthesized on experiment in 2010 [21]. As anode materials, the 2D graphdiyne has been confirmed with a high-efficiency on theoretical and experimental studies [22]. A wealth of carbon allotropes
have been theoretically predicted as the superior LIB anode materials, like ψ-graphene, biphenylene, phagraphene, popgraphene, xgraphene and graphenylene [23-29]. With the development of technologies, it is necessary and possible to explore new anode materials. The basic demands for the target material: (1) light mass and low areal density [9,30] (2) the higher lithium capacity and lower diffusion barrier [9,10,31] (3) the higher Li passing rate and impermeable of electrolytes. Based on these conditions, we suggest that the theoretically predicted sp2 fused pentagon network is suitable for our aim [32]. By the ab initio molecular dynamics (AIMD), we find that it can be synthesized from the acepentalene structure sharing three edges with three adjacent pentagon trimmers [32], and the approach has been successfully employed in the synthesis of graphene sheet, and nanoribbons as well as some other nanostructures [33-38]. According to our detailed first principle calculations, the pentagon network was confirmed to be stable. Meanwhile, there are uniform pentagon and dodecagon pores for the adsorptions and diffusion of the Li atoms as an electrode material. From these conditions, fused pentagon carbon network is expected to satisfy the requirements of anode materials. In this paper, by using first-principle calculations based on the density functional theory (DFT), we have explored the diffusion efficiency and storage capacity of lithium in the fused pentagon carbon network. Both monolayer and bilayer systems are considered in our calculations. The penetration of the lithium ion and molecules from electrolyte are studied by the nudge elastic band (NEB) method. What’s more, the electronic properties, carrier velocity and open-circuit voltage are also calculated. High lithium capacity, low diffusion barrier, and electronic properties provide excellent conditions for fused pentagon network to become the anode material. 2. Methods Our first-principles calculations were performed within the framework of density functional theory (DFT), with a plane wave basis set as implemented in the Vienna ab initio simulation package
(VASP) [39,40]. The projector augmented wave (PAW) method was used. The cutoff energy for the plane-wave basis was set to 500 eV. The exchange and correlation energies are described by using a generalized gradient approximation (GGA) and Perdew, Burke, and Ernzerhof (PBE) parameterization [40,41]. The fused pentagon network sheet was placed in the xy plane of the supercell with a 16 Å vacuum in the z lattice, which is large enough to ignore the effects from neighboring images. The sampling k points in the first Brillouin zone was set to be 15×15×1 to integrate the electronic properties [42]. All the atoms here were fully relaxed until the force and energy were converged to 0.01 eV/Å and 10-6 eV. The phonon calculation was performed by using the Phonopy code with the finite displacement method [43,44], interfaced with the density functional perturbation theory as implemented in VASP. In phonon calculation, the cutoff energy was set to 500 eV, accompanied by more stringent convergence criteria for energy (10-7eV) and force (0.1 meV/Å). Ab initio molecular dynamics (AIMD) simulations were performed to estimate the stability. The temperature was maintained constant using a Nose´-Hoover method. The lithium diffusion barrier was calculated by the nudge elastic band (NEB) algorithm [45]. Van der Waals correction (vdW-D3) was considered in the calculation [46]. 3. Results and discussion The structure of fused pentagon carbon network is shown in Fig. 1(a). The optimal lattice constants are a=b=7.14 Å, which are in good agreement with previous predictions [32,47]. There are three chemically inequivalent carbon atoms in one unit cell, which are marked by the different colors. These carbon atoms would form the C-C bonds with a sp2 hybridization with three neighboring carbon atoms, giving a uniform pentagon and twelve-sided rings. In the Fig. 1(b), we give the stability diagram of the carbon allotropes. We can find that the energy per atom of the fused pentagon network is lower than that of the experimentally synthesized graphdiyne while it is higher than that of graphene. For the
carbon density, fused pentagon network is lower than graphene, and higher than graphdiyne. From this energy-based ordering, we assume that the metastable fused pentagon networks can be synthesized experimentally. Considered from the energies per atom and carbon areal density, the fused pentagon carbon network likely to be synthesized. Moreover, we calculate the phonon spectrum and molecular dynamics of fused pentagon carbon network. In the Fig. 1(c), there is no imaginary mode in the whole Brillouin zone, suggesting the dynamic stability with small atomic displacements. We also carefully carry on ab initio molecular dynamics (AIMD) simulation in Fig. 1(d). After the AIMD simulation for 10 ps, the structure at the end simulations has a slight distortion, which informed that the planar structure can retain its stable configuration at 1000 K. After the relaxation, it can back to the original configuration quickly. In addition, we also calculate the cleavage energy about 0.23 J/m2, being well comparable with other vdW bonded materials of great interest: 0.43 J/m2 has been calculated for graphite, 0.27 J/m2 for MoS2 and 0.30 J/m2 for CrI3 [48,49]. These results suggest that this carbon material is quite stable. We calculate the electronic properties of the fused pentagon carbon network. The calculated energy band structures and the DOS are presented in Fig. 2(a). There is no gap between the valence and conduction bands, showing a metal characteristic. The charge carriers are evaluated to 8.3×105 m/s velocity agreeing with that of graphene [50]. Further, we can see that the orbitals around the Fermi level are mainly pz orbitals, which form the weak π bonding. For the s, px and py orbitals, they can hybridize together at a deep energy level, forming the strong σ bonds in the plane. Moreover, we calculate the electron localization function (ELF) for the bonding feature in Fig. 2(b). The values range of ELF is from 0.0 to 1.0. The value 0.0 refers to the lowest charge density, 0.5 and 1.0 indicate that the fully delocalized and localized electrons. ELF value between two neighboring C atoms is about 0.9, which represents a strong σ bonding states by the x, px and py orbitals in the deep levels. It confirms the covalent-like nature of C-C bonds in the fused pentagon network. The delocalized π
bonds are from the pz orbitals, giving rise to metallicity of the structure. Due to the excellent structural and electronical properties, the fused pentagon carbon network can be as the candidate anode material of the Li ion batteries. First, we should consider the adsorptions of Li atoms on the fused pentagon carbon network. We use a 2x2 supercell as substrate to avoid the interaction between Li adatoms. The absorption energy can be defined by formula: 𝐸𝑎𝑑𝑠 =
𝑛𝐸𝐿𝑖 + 𝐸𝑀 ― 𝐸𝐿𝑖𝑛𝑀 𝑛
𝐸𝐿𝑖𝑛𝑀 and 𝐸𝑀 are the total energies of fused pentagons network supercell with and without lithium atom adsorption, respectively. 𝐸Li is the energy per Li in the bulk Li metal. There are eight unequal possible sites to adsorb Li atom as shown in Fig. 3(a). The H1 and H2 are the hollow sites of the pentagonal and twelve-sided rings. The T1, T2 and T3 are the top sites of unequal carbon atoms. The B1, B2 and B3 are the bridge sites of different C-C bonds. Our results show that the H1 site is energetically most favorable, and the calculated adsorption energy is about -0.94 eV. The negative adsorption energies indicate that Li atoms will not cluster and preferably bind at the H1 site. For the hollow site of twelve-sided ring, the Li atom would not be located on the center ring due to a large diameter of the twelve-sided ring. It can connect with the neighboring carbon atoms forming few Li-C bonds and the adsorption energy is about -0.66 eV. For other adsorption sties, the adsorbed configurations are not stable, and the Li atom would move to the hollow site of pentagonal ring. For the LIBs, it is required that more Li ions can be adsorbed on the anode materials, getting a large storage capacity. Then we would put more lithium atoms on fused pentagonal network one by one, as shown in Fig. S1(a), until the adsorption energy per lithium atom has a positive value. Our results show that at least 16 lithium atoms are attached to the surface of monolayer 2x2 supercell, and the average adsorption energy was -0.24 eV per Li atom. Then there are no visible distortion in the fused pentagon carbon network. The theoretical capacity of the results was 637.8 mAh/g. If the Li atoms are adsorbed on two sides of the monolayer carbon materials, the number of Li atoms can reach
28 and the corresponding adsorption energy is -0.19 eV in Fig. S1(b). The theoretical capacity is 1116.2 mAh/g. Next, we define the average open-circuit voltage by 𝑂𝐶𝑉 ≈
𝐸𝐿𝑖𝑥1 𝐹𝑃𝑁 ― 𝐸𝐿𝑖𝑥2 𝐹𝑃𝑁 + (𝑥2 ― 𝑥1)𝜇𝐿𝑖 (𝑥2 ― 𝑥1)𝑒
Where 𝐸𝐿𝑖𝑥1 and 𝐸𝐿𝑖𝑥2 correspond to different Li loadings of the fused pentagon network. 𝐸𝐿𝑖𝑥1 𝐹𝑃𝑁 and 𝐸𝐿𝑖𝑥2 𝐹𝑃𝑁 are the total energies of these Lix1 and Lix2 adsorbed fused pentagon network sheets, respectively. 𝜇𝐿𝑖 is the chemical potential calculated as the energy per atom of Li bulk. For the detailed description for the intercalation process, the OCV curve was shown in Fig. S2. The OCV was declined with the Li loading on the fused pentagon network in the overall trend. From the fifth atom, it will be located on the other side of the fused pentagon network, and the adsorption energy has an increase, which is responsible for the increase of the fifth point in the Fig. S2. The average OCV calculated by averaging the voltage profile versus Li concentration is found to be 0.28 V for the fused pentagon carbon network, which is slightly higher than that of graphite (0.11 V), but much lower than that of 2D VS2 (0.93 V) [51], Mo2C (0.68 V) [52] , popgraphene (0.45 V) [53], and ψ-graphene (0.64 V) [23]. An important influencing factor for LIBs anode material is that the mobility of lithium ions on the fused pentagon carbon network. For the monolayer fused carbon materials, the pentagonal rings are the preferred adsorption sites of Li atoms, so the migration should occur between the pentagonal rings mainly. During the diffusion of Li adatoms on the surface, they need cross the bridge sites of C-C bonds. Looking the structure of the fused carbon network, we find that there are two unequal C-C bonds, including the C-C bond in the acepentalene molecule (marked by blue) and the shared C-C bond between the acepentalene molecules (marked by orange), as shown in Fig. 3(b). From its preferred adsorption site to the nearest-neighbor stable adsorption site, we consider two migration pathways of Li adatoms, crossing these two different C-C bridge sites, as shown by Path 1 and Path
2. For the study of diffusion migration pathways, we use the CI-NEB method, and the corresponding energy barriers are shown in Fig. 3(c). We can see that the diffusion energy barrier in acepentalene molecule is 0.23 eV from the Path 1. For crossing the C-C bonds shared by the molecule, the energy barrier is only 0.12 eV from Path 2. The energy barriers are lower than that of phagraphene (0.420.08eV) [26], popgraphene (0.36-0.3 eV) [27], graphite (0.4-0.218 eV) [54]. During practical applications, LIBs anode materials are usually used by stacking multiple layers, it is worth to study the interaction between the layers. In the paper, we consider five stacking configurations of bilayer. We test AA stacking configuration and four different AB stacking configurations, which are shown in Fig. S3. By the calculations, the AA stacking is the ground state configuration, which is more stable than these AB configurations by 2.1 meV, 2.7 meV, 2.9 meV and 4.2 meV per atom, respectively. The AA stacking has the lowest energy, which would be considered in the multilayers stacking. In addition, for the AA stacking, the phonon spectrum has no virtual frequency, and the molecular dynamics displays that structure can maintain the stability of the overall configuration within 300 K and 10 ps, indicating that the stability of the structure is reliable, shown in Fig. S4. In the practical charging and discharging process, the Li atoms would also diffuse between the layers. Following, we study the effects of the multilayer on the diffusion. First, we study the diffusion outer surface of bilayer. The Li atoms would move between the pentagonal rings, and the diffusion pathways are same with that in Fig. 3(b). As shown in Fig. 4(a), the corresponding calculated energy barriers are 0.22 eV and 0.14 eV. There are a light change due to the effect of other layer. For the diffusion in the interlayer interstitial in Fig. 4(b), the energy barriers are 0.17 eV and 0.10 eV, respectively. The diffusion is easier for the Li atoms in the interlayer. While in the practical working process, the Li atoms need to move different layers. As shown in Fig. 4(c), the Li atoms need to move the hollow site of twelve rings firstly, and then cross the large hole to reach the interlayer interstitial.
We can see that the energy barrier mainly arises from the energy costing of crossing the shared C-C bond between the pentagonal ring and dodecagon ring, about 0.25 eV. From the hollow site upper to the interlayer interstitial, the energy barrier is only 0.03 eV. Comparing all the energy barriers, the diffusions of Li atoms in the anode materials occur easily, which is beneficial for practical application. It indicates that there is a good charge-discharge ability for fused pentagon carbon network in the battery. Based on the discussion above, the dodecagon carbon rings of fused pentagon network could permit lithium atoms to penetrate the anode materials favorably. In the common organic electrolytes, these
molecules,
including
EC(C3H4O3),
PC(C5H7O6),
DEC(C5H10O3),
DMC(C3H6O3),
EMC(C4H8O3) [55], would be limited through the holes. In the paper, we study the possibility of EC molecule through the hole, which has the smallest size. We calculate the energy barrier through the hole by the NEB method in the Fig. 5(a). The energy barrier is about 11 eV, which is too large to cross the hole. The diameter of the hole is only 5.43 Å, and the distance between the EC molecule and the edge of the ring is about 1.5 Å with z=0 plane, which is in the range of bonding. As shown in Fig. 5(b), we give the electron density distributions with z=0, and there is a large overlap of electron densities between the EC molecule and the pore rim of dodecagon carbon ring, hindering the passing event of EC molecule. 4. Conclusion In summary, we study the possibility of fused pentagon carbon network as the anode materials via first-principles calculations. First, we give the phonon spectrum and AIMD calculation of the fused pentagon carbon network, confirming the dynamic stability. The carbon material shows a metallic behavior with a carrier velocity about 8.3×105 m/s, which is beneficial for the efficiency of Li ion batteries. For the adsorbed configurations, the Li atom prefers to be located on the pentagonal rings. When more Li atoms are adsorbed on single side or two sides of the monolayer sheet, the
capacities can reach 637.8 mAh/g (LiC3.5) and 1116.2 mAh/g (LiC2), respectively. For the diffusion, the maximum energy barrier arises from the interlayer penetration, only 0.25 eV, indicating that the Li atoms can move in the anode materials easily. Besides, the OCV is also calculated about 0.28 V. These attractive theoretical calculation results demonstrate that fused pentagon carbon network is a promising multifunctional material in lithium-ion batteries. Acknowledgments This work was supported by the National Natural Science Foundation of China (Grant No: 11704153), the Natural Science Foundation of Shandong Province (Grant No: ZR2017LA009), and the fund from University of Jinan (Grant No: XKY1707).
References [1] G. C. Guo, D. Wang, X. L. Wei, Q. Zhang, H. Liu, W. M. Lau, L. M. Liu, First-Principles Study of Phosphorene and Graphene Heterostructure as Anode Materials for Rechargeable Li Batteries, J. Phys. Chem. Lett. 6 (2015) 5002. [2] Y. S. Meng, M. E. Arroyo-de Dompablo, First principles computational materials design for energy storage materials in lithium ion batteries, Energy Environ. Sci. 2 (2009) 589. [3] J. M. Tarascon, M. Armand, Issues and challenges facing rechargeable lithium batteries, Nature 414 (2001) 359. [4] S.-H. Zhou, J. Zhang, Z.-Z. Ren, J.-F. Gu, Y.-R. Ren, S. Huang, W. Lin, Y. Li, Y.-F. Zhang, W.-K. Chen, First-principles study of MoSSe_graphene heterostructures as anode for Li-ion batteries, Chem. Phys. 529 (2020) 110583. [5] S. Goriparti, E. Miele, F. De Angelis, E. Di Fabrizio, R. Proietti Zaccaria, C. Capiglia, Review on recent progress of nanostructured anode materials for Li-ion batteries, J. Power Sources 257 (2014) 421. [6] G. Zhu, K. Lü, Q. Sun, Y. Kawazoe, P. Jena, Lithium-doped triazine-based graphitic C3N4 sheet for hydrogen storage at ambient temperature, Comput. Mater. Sci. 81 (2014) 275. [7] M. D. Bhatt, C. O'Dwyer, Recent progress in theoretical and computational investigations of Liion battery materials and electrolytes, Phys. Chem. Chem. Phys. 17 (2015) 4799. [8] W.-M. Zhang, J.-S. Hu, Y.-G. Guo, S.-F. Zheng, L.-S. Zhong, W.-G. Song, L.-J. Wan, Tin-
Nanoparticles Encapsulated in Elastic Hollow Carbon Spheres for High-Performance Anode Material in Lithium-Ion Batteries, Adv. Mater. 20 (2008) 1160. [9] H. Li, H. Zhou, Enhancing the performances of Li-ion batteries by carbon-coating: present and future, Chem. Commun. (Camb) 48 (2012) 1201. [10] X. Meng, X. Q. Yang, X. Sun, Emerging applications of atomic layer deposition for lithium-ion battery studies, Adv. Mater. 24 (2012) 3589. [11] J. Wang, X. Sun, Understanding and recent development of carbon coating on LiFePO4 cathode materials for lithium-ion batteries, Energy Environ. Sci. 5 (2012) 5163. [12] S. Xu, R. M. Jacobs, H. M. Nguyen, S. Hao, M. Mahanthappa, C. Wolverton, D. Morgan, Lithium transport through lithium-ion battery cathode coatings, J. Mater. Chem. A 3 (2015) 17248. [13] H. Chakraborti, S. K. Pal, Assessment of amine functionalized graphene nanoflakes for anode materials in Li-ion batteries: An ab initio study, Chem. Phys. Lett. 600 (2014) 118. [14] E. Yoo, J. Kim, E. Hosono, H.-S. Zhou, T. Kudo, I. Honma, Large Reversible Li Storage of Graphene Nanosheet Families for Use in Rechargeable Lithium Ion Batteries, Nano Lett. 8 (2008) 2277. [15] Z. Jiang, B. Pei, A. Manthiram, Randomly stacked holey graphene anodes for lithium ion batteries with enhanced electrochemical performance, J. Mater. Chem. A 1 (2013) 7775. [16] Y. Yan, Y.-X. Yin, S. Xin, Y.-G. Guo, L.-J. Wan, Ionothermal synthesis of sulfur-doped porous carbons hybridized with graphene as superior anode materials for lithium-ion batteries, Chem. Commun. 48 (2012) 10663. [17] X. Li, D. Geng, Y. Zhang, X. Meng, R. Li, X. Sun, Superior cycle stability of nitrogen-doped graphene nanosheets as anodes for lithium ion batteries, Electrochem. Commun. 13 (2011) 822. [18] G. Li, Y. Li, H. Liu, Y. Guo, Y. Li, D. Zhu, Architecture of graphdiyne nanoscale films, Chem. Commun. 46 (2010) 3256. [19] J. Zhang, Y. Zhou, G. Zheng, Q. Huang, X. Zheng, P. Liu, J. Zhang, X. Guan, Novel assembly and electrochemical properties of anatase TiO2-graphene aerogel 3D hybrids as lithium-ion battery anodes, Chem. Phys. Lett. 662 (2016) 214. [20] H. H. Tran, P. H. Nguyen, V. H. Cao, L. T. Nguyen, V. M. Tran, M. L. P. Le, S.-J. Kim, V. Vo, SnO2 nanosheets/graphite oxide/g-C3N4 composite as enhanced performance anode material for lithium ion batteries, Chem. Phys. Lett. 715 (2019) 284. [21] X. Zhu, Z. Meng, H. Ying, X. Xu, F. Xu, W. Han, A novel CoS2/reduced graphene oxide/multiwall carbon nanotubes composite as cathode for high performance lithium ion battery, Chem. Phys. Lett. 684 (2017) 191.
[22] C. Huang, S. Zhang, H. Liu, Y. Li, G. Cui, Y. Li, Graphdiyne for high capacity and long-life lithium storage, Nano Energy 11 (2015) 481. [23] X. Li, Q. Wang, P. Jena, ψ-Graphene: A New Metallic Allotrope of Planar Carbon with Potential Applications as Anode Materials for Lithium-Ion Batteries, J. Phys. Chem. Lett. 8 (2017) 3234. [24] D. Ferguson, D. J. Searles, M. Hankel, Biphenylene and Phagraphene as Lithium Ion Battery Anode Materials, ACS Appl. Mater. Interfaces 9 (2017) 20577. [25] F. Schlütter, T. Nishiuchi, V. Enkelmann, K. Müllen, Octafunctionalized biphenylenes: molecular precursors for isomeric graphene nanostructures, Angew. Chem. Int. Ed. 53 (2014) 1538. [26] Z. Wang, X. F. Zhou, X. Zhang, Q. Zhu, H. Dong, M. Zhao, A. R. Oganov, Phagraphene: A Low-Energy Graphene Allotrope Composed of 5-6-7 Carbon Rings with Distorted Dirac Cones, Nano Lett. 15 (2015) 6182. [27] S. Wang, B. Yang, H. Chen, E. Ruckenstein, Popgraphene: a new 2D planar carbon allotrope composed of 5-8-5 carbon rings for high-performance lithium-ion battery anodes from bottom-up programming, J. Mater. Chem. A, 6 (2018) 6815. [28] S. Wang, Y. Si, B. Yang, E. Ruckenstein, H. Chen, Two-Dimensional Carbon-Based Auxetic Materials for Broad-Spectrum Metal-Ion Battery Anodes, J. Phys. Chem. Lett. 10 (2019) 3269. [29] Y.-X. Yu, Graphenylene: a promising anode material for lithium ion batteries with high mobility and storage, J. Mater. Chem. A 1 (2013) 13559. [30] K. Min, S. W. Seo, B. Choi, K. Park, E. Cho, Computational Screening for Design of Optimal Coating Materials to Suppress Gas Evolution in Li-Ion Battery Cathodes, ACS Appl. Mater. Interfaces 9 (2017) 17822. [31] X. Xiao, P. Lu, D. Ahn, Ultrathin Multifunctional Oxide Coatings for Lithium Ion Batteries, Adv. Mater. 23 (2011) 3911. [32] M. Maruyama, S. Okada, Two-dimensional sp2 carbon networks of fused pentagon, Jpn. J. Appl. Phys. 53 (2014) 06JD02. [33] Z. Li, P. Wu, C. Wang, X. Fan, W. Zhang, X. Zhai, C. Zeng, Z. Li, J. Yang, J. Hou, LowTemperature Growth of Graphene by Chemical Vapor Deposition Using Solid and Liquid Carbon Sources, ACS Nano 5 (2011) 3385. [34] J. Cai, P. Ruffieux, R. Jaafar, M. Bieri, T. Braun, S. Blankenburg, M. Muoth, A. P. Seitsonen, M. Saleh, X. Feng, K. Mullen, R. Fasel, Atomically precise bottom-up fabrication of graphene nanoribbons, Nature 466 (2010) 470. [35] Y. C. Chen, D. G. de Oteyza, Z. Pedramrazi, C. Chen, F. R. Fischer, M. F. Crommie, Tuning the Band Gap of Graphene Nanoribbons Synthesized from Molecular Precursors, ACS Nano 7 (2013)
6123. [36] H. Chen, Y. Yang, Z. Hu, K. Huo, Y. Ma, Y. Chen, X. Wang, Y. Lu, Synergism of C5N SixMembered Ring and Vapor−Liquid−Solid Growth of CNx Nanotubes with Pyridine Precursor, J. Phys. Chem. B 110 (2006) 16422. [37] L. Grill, M. Dyer, L. Lafferentz, M. Persson, M. V. Peters, S. Hecht, Nano-architectures by covalent assembly of molecular building blocks, Nat. Nanotechnol. 2 (2007) 687. [38] S. Beniwal, J. Hooper, D. P. Miller, P. S. Costa, G. Chen, S.-Y. Liu, P. A. Dowben, E. C. H. Sykes, E. Zurek, A. Enders, Graphene-like Boron−Carbon−Nitrogen Monolayers, ACS Nano 11 (2017) 2486. [39] G. Kresse, J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54 (1996) 11169. [40] G. Kresse, D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method, Phys. Rev. B 59 (1999) 1758. [41] J. P. Perdew, K. Burke, M. Ernzerhof, Generalized Gradient Approximation Made Simple, Phys. Rev. Lett. 77 (1996) 3865. [42] H. J. Monkhorst, J. D. Pack, Special points for Brillouin-zone integrations, Phys. Rev. B 13 (1976) 5188. [43] K. Parlinski, Z. Q. Li, Y. Kawazoe, First-Principles Determination of the Soft Mode in Cubic ZrO2, Phys. Rev. Lett. 78 (1997) 4063. [44] A. Togo, I. Tanaka, First principles phonon calculations in materials science, Scr. Mater. 108 (2015) 1. [45] G. Henkelman, H. Jónsson, Improved tangent estimate in the nudged elastic band method for finding minimum energy paths and saddle points, J. Chem. Phys. 113 (2000) 9978. [46] S. Grimme, J. Antony, S. Ehrlich and H. Krieg, A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu, J. Chem. Phys., 132 (2010) 154104. [47] M. Maruyama, S. Okada, Two-Dimensional sp2 Carbon Network of Fused Pentagons: All Carbon Ferromagnetic Sheet, Appl. Phys. Express 6 (2013) 095101. [48] T. Björkman, A. Gulans, A. V. Krasheninnikov, R. M. Nieminen, van der Waals Bonding in Layered Compounds from Advanced Density-Functional First-Principles Calculations, Phys. Rev. Lett. 108 (2012) 235502. [49] M. A. McGuire, H. Dixit, V. R. Cooper, B. C. Sales, Coupling of Crystal Structure and Magnetism in the Layered, Ferromagnetic Insulator CrI3, Chem. Mater. 27 (2015) 612.
[50] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, M. I. Katsnelson, I. V. Grigorieva, S. V. Dubonos, A. A. Firsov, Two-dimensional gas of massless Dirac fermions in graphene, Nature 438 (2005) 197. [51] J. Yu, Z. Zhen, C. R. Cabrera, Z. Chen, Metallic VS2 Monolayer: A Promising 2D Anode Material for Lithium Ion Batteries, J. Phys. Chem. C 117 (2013) 25409. [52] D. Çakır, C. Sevik, O. Gülseren, F. M. Peeters, Mo2C as a high capacity anode material: a firstprinciples study, J. Mater. Chem. A 4 (2016) 6029. [53] S. Wang, B. Yang, H. Chen, E. Ruckenstein, Reconfiguring graphene for high-performance metal-ion battery anodes, Energy Storage Materials 16 (2019) 619. [54] J. Liu, S. Wang, Q. Sun, All-carbon-based porous topological semimetal for Li-ion battery anode material, Proc. Natl. Acad. Sci. U.S.A. 114 (2017) 651. [55] J. B. Goodenough, Y. Kim, Challenges for Rechargeable Li Batteries, Chem. Mater. 22 (2010) 587.
Fig. 1 (a) Structure of fused pentagon carbon network: concluding three types of unequal carbon atoms marked by blue, green and red, respectively. (b) Stability diagram of the common carbon allotropes. (c) Phonon spectrum of fused pentagon carbon network. (d) Evolution of potential energy per atom versus simulation time. The insets I and II are the initial and final structures of the simulations, respectively.
Fig. 2 (a) The orbital-resolved bandstructures of fused pentagon carbon network (left) and the DOS (right). (b) The calculated ELF which shows the covalent–like bonding nature in the fused pentagon carbon network.
Fig. 3 (a) Adsorption sites of Li atom on monolayer fused pentagon carbon network. (b)-(c) The possible migration paths and the corresponding diffusion barrier profiles of Li diffusion on fused pentagon carbon network.
Fig. 4 (a) and (b) The migration paths and the corresponding diffusion barriers of Li on the outer surface and in the interlayer interstitial of bilayer. (c) The permeability of Li atom among the different layers.
Fig. 5 (a) Potential energy profiles of EC molecule through the largest pore of fused pentagon carbon network. (b) The electron density distribution at an iso value of 0.05 Bohr/Å3 for the states where z=0 Å.
Fig. S1 (a) and (b) The structures of the maximum Li atoms adsorbed on the single side and double sides of monolayer fused carbon network, respectively. The atoms on the upper and lower surface are marked by green and yellow, respectively.
Fig. S2 The OCV curve, x corresponds to different Li loading of the fused pentagon network.
Fig. S3 (a) Configuration of AA stacking. (b)-(e) Four different configurations of AB stacking. The A and B layers are marked by gray and yellow, respectively. The AA stacking is the ground state. The below values are the relative energies per atom for these different AB configurations.
Fig. S4 (a) Phonon spectrum and (b) Evolution of potential energy per atom versus simulation time of AA stacking fused pentagon carbon network. Molecular dynamics simulation at 300K.
We study the fused pentagon network as the anode materials. The theoretical lithium storage capacities can reach 637.8 mAh/g and 1116.2 mAh/g for the single side adsorptions and double sides adsorptions, respectively. The diffusion barriers are below 0.25 eV, leading a high lithium mobility. It has the excellent metallic properties.
Dear editor, At the requirement, we are now listing the highlights of our paper as below for your convenience. (1) The fused pentagon carbon network has a high lithium storage capacity. (2) The Li atom has a low diffusion barrier. (3) The anode material has the excellent electronic properties. Yours sincerely, Hongbo Wang