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Carbon-coated vanadium selenide as anode for lithium-ion batteries and sodium-ion batteries with enhanced electrochemical performance
Materials Letters 189 (2017) 152–155
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Carbon-coated vanadium selenide as anode for lithium-ion batteries and sodium-ion batteries with enhanced electrochemical performance Xinhui Yang, Zhian Zhang n School of Metallurgy and Environment, Central South University, Changsha 410083, China
art ic l e i nf o
a b s t r a c t
Article history: Received 27 September 2016 Received in revised form 29 November 2016 Accepted 1 December 2016 Available online 2 December 2016
A Carbon-coated vanadium selenium composites were synthesized through a facile ball-milling method. The VSe2/C presents a structure that carbon layer covers around the pure VSe2 particles. The VSe2/C exhibits outstanding performances in electrochemical tests, showing an enhanced cycle capacities of 467 mA h g 1 for sodium-ion batteries and 453 mA h g 1 for lithium-ion batteries after 50 dischargecharge cycles. & 2016 Elsevier B.V. All rights reserved.
Keywords: Vanadium selenium Carbon-coating Ball-milling Lithium-ion batteries Sodium-ion batteries
1. Introduction
2. Experimental section
Nowadays lithium-ion batteries (LIBs) have been widely developed in electronic equipment, electric tools, electric vehicles, and power system [1,2]. Meanwhile, sodium-ion batteries (SIBs) are being recognized as an alternative to LIBs because of the elemental similarities between lithium and sodium and abundant sodium resources [3]. However, Na þ has a larger radius than Li þ , which makes it important for SIBs to find an appropriate anode material as replacement [4]. Two-dimensional transition metal dichalcogenides MX2 (M ¼ Mo, Ti, W, V, etc. X ¼S, Se) have shown excellent mechanical and electrochemical performances in many researches [5–9]. Vanadium selenide is a kind of MX2 crystals that has typical layered structure and lighter molecular mass than most MX2, which makes its theoretical capacity higher. As early as 1978, Whittingham et al. used VSe2 firstly in lithium cells [10]. In 2015 Li et al. synthesized VSe2/graphene nanocomposites as anode materials for LIBs [8]. Herein, VSe2/C composites synthesized by a facile ball-milling method are used as anode material for LIBs and SIBs for the first time. After further hybridize with Super P, a carbon layer is formed outside the VSe2 particles, which work as a conductive matrix as well as a buffer for volume change of VSe2 during Li þ and Na þ insertion and extraction [5,11]. The VSe2/C exhibits excellent electrochemical properties, making it an appropriate application for LIBs and SIBs.
The VSe2/C was synthesized by a ball-milling method. 0.5094g vanadium powder, 1.5792g selenium powder and Super P were placed into a planetary Ball Mill and react at the rate of 400 rpm for 8 h. The precursor was transferred into a tube furnace and heated in 600 °C for 3 h. For comparison, pure VSe2 was synthesized in the same way without the participation of Super P. Scanning electron microscopy (SEM, Nova NanoSEM 230), transmission electron microscopy (TEM, Tecnai G2 20ST), Powder X-ray diffraction (XRD, Rigaku3014) and thermogravimetric analysis (TGA, SDTQ600) were employed to character. Active material was mixed with Super P, sodium alginate at the ratio of 8:1:1 to prepare electrode. The CR2025 coin-type cells were assembled in argon-filled glove box. The electrolyte chosen for LIB was 1 M LiPF6 in ethylene carbonate/dimethyl carbonate/ diethyl carbonate (1:1:1 in volume) and for SIB was composed of 1 M NaClO4 in ethylene carbonate/diethyl carbonate (1:1 in volume) with another 5 wt% fluoroethylene carbonate. Lithium/sodium plate and Celgard 2400 were used as the counter electrode and separator respectively. Galvanostatic charge-discharge (LAND CT2001A) and cyclic voltammetry tests (PARSTAT 2273 electrochemical measurement system) were carry out to detect electrochemical properties of VSe2/C.
n
Corresponding author.
http://dx.doi.org/10.1016/j.matlet.2016.12.001 0167-577X/& 2016 Elsevier B.V. All rights reserved.
3. Result and discussion To figure out the accurate content of VSe2 in VSe2/C composites,
X. Yang, Z. Zhang / Materials Letters 189 (2017) 152–155
Fig. 1. (a) TGA curves of VSe2 and VSe2/C; (b) XRD patterns of VSe2 and VSe2/C.
Fig. 2. SEM and TEM images of VSe2 (a, b, c) and VSe2/C (d, e, f); Elemental mapping image of VSe2/C.
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X. Yang, Z. Zhang / Materials Letters 189 (2017) 152–155
TGA was conducted from room temperature to 800 °C under air atmosphere. As Fig. 1a shows, the weight loss of pure VSe2 and VSe2/C composites are respectively 53.01% and 60.07%. At first, both samples present a little weight increase between about 200 °C and 350 °C, which can be attributed to the oxidation of VSe2 and the formation of solid VO2 and SeO2[9,12]. After 350 °C, apparent weight loss appears in the curve of VSe2/C sample, because of the sublimation of SeO2 and complete oxidation of carbon matrix. Therefore, suppose that the weight loss of VSe2/C is equal to the sum weight loss of the pure VSe2 and the weight of its carbon layer. If we illustrate alpha ‘m’ to represent the total mass of VSe2/C composites, ‘n’ with the percentage composition of VSe2 in the VSe2/C composites, we can get an equation: 60.07% m ¼53.01% m n þm (1 n) [9]. Consequently, the VSe2 loading in VSe2/C composites is calculated to be 85%. The XRD was used to investigate the phase and crystal structure of samples. All the diffraction peaks of the VSe2 material and VSe2/C illustrated in Fig. 1b are perfectly marching with the standard VSe2 pattern (JCPDS card number: 89-1641), indicating that the synthesized samples are all highly purified and have typical crystal structure. However, there is no peak of carbon black observed in the patterns of VSe2/C. Combine with Raman pattern (Fig. S1), the carbon in composites exists in amorphous form. Fig. 2 shows the morphology images of VSe2 and VSe2/C. From Fig. 2a, the pure VSe2 appears to be some uneven agglomerates with a size of about several microns. VSe2/C particles become rough with white layers outside. Further detection through TEM illustrated in Fig. 2b and e have been conducted to confirm the structure that carbon covers around VSe2 particle. Fig. 2c shows only the orthometric VSe2 crystal lattice lines while Fig. 2f shows both the VSe2 and its covering amorphous carbon layer. Moreover, the energy dispersive X-ray spectroscopy (EDS) elemental mapping images of VSe2/C is shown in Fig. 2 demonstrates the elemental mapping image. V and Se scatters evenly in their pictures, while the carbon concentrates more on the edge of the certain particle. The carbon coat will can buffer the VSe2 from volume change (Fig. S2). The electrochemical performances of samples in SIBs are
demonstrated in Fig. 3. Fig. 3a describes their cycling performances. The discharge capacity of VSe2/C reaches 651 mA h g 1 initially, then decreases to 553 mA h g 1 in the second cycle with a relatively low Coulombic efficiency at 80%. Because that Na þ intercalate into VSe2 interlayer and a interphase between the solid/ electrolyte (SEI) forms [9]. After 50 discharge-charge cycles the VSe2/C contains a reversible capacity of 467 mA h g 1 without any marked loss and an efficiency approaching to 100%. For comparison, the VSe2 sample undergoes a sharply capacity decline and falls to 49 mA h g 1 after 50 cycles. The CV curves are displayed in Fig. 3b, which is parallel with most MX2. During discharge process, two reduction peaks at 1.4 V and 0.2 V arise in the first cycling that can be attribute to the insertion of Na þ , which generates the compound NaxVSe2 and NaxSe, and finally becomes Na2Se and V. On the other hand, oxidation peaks around 1.6 V and 2.2 V show up in charge process, which is mainly due to the extraction process of Na þ . Another reduction peak shows up at about 0.2 V due to the forming of SEI [13]. Fig. 3c shows the performances under different current densities from 50 to 2000 mA g 1. VSe2/C reversibly delivers the capacities of 437, 375, 326, 309, 263 and 132 mA h g 1, and efficiency is approaching to 100% at last. The lithium-storage properties are also illustrated in Fig. 3. The VSe2/C performs an initial discharge capacity as high as 592 mA h g 1. A sudden fall rises up in the second cycle blame for the Li þ intercalation into interlayer of VSe2 as well as irreversible reactions like decomposition of electrolyte. After 50 cycles, VSe2/C still holds a reversible capacity of 453 mA h g 1 while pure VSe2 fades very quickly to 54 mA h g 1 after 50 cycles. Fig. 3e presents the CV curves of VSe2/C. Two reduction peak at about 1.5 V can be observed in the first cycling that can be attribute to the insertion of Li þ . On the other hand, oxidation peaks around 1.8 V and 2.2 V appear in the initial cycle, which is mainly due to the extraction process of Li þ . Fig. 3f shows the capacity of the VSe2/C under different current densities from 100 to 4000 mA g 1, with the discharge capacities of 441, 429, 390, 308, 236 and 147 mA h g 1.
Fig. 3. Electrochemical performance of VSe2 and VSe2/C for SIBs (a, b, c) and LIBs (d, e, f). (a) Cycling performance at a current density of 100 mA g 1. (b) Cyclic voltammogram profiles of VSe2/C at a scan rate of 0.2 mV s 1. (c) Discharge capacity and efficiency of VSe2/C under different current densities. (d) Cycling performance at a current density of 200 mA g 1. (e) Cyclic voltammogram profiles of VSe2/C at a scan rate of 0.2 mV s 1. (f) Discharge capacity and efficiency of VSe2/C under different current densities.
X. Yang, Z. Zhang / Materials Letters 189 (2017) 152–155
4. Conclusion To conclude, a carbon-coated vanadium selenium composites were successfully synthesized through ball-milling method by commercial vanadium, selenium and Super P powder. The consequent VSe2/C was examined by some material characterizations and electrochemical tests, presenting a reversible capacities of 467 mA h g 1 for SIBs and 453 mA h g 1 for LIBs. Because of the high capacity and excellent cycle stability, as well as the facile production method, the VSe2/C composites are expected a promising anode material for both LIBs and SIBs.
Appendix A. Supplementary material Supplementary data associated with this article can be found in the online version at http://dx.doi.org/10.1016/j.matlet.2016.12. 001.
References [1] M. Armand, J.M. Tarascon, Building better batteries, Nature 451 (7179) (2008) 652–657. [2] M.M. Thackeray, C. Wolverton, E.D. Isaacs, Electrical energy storage for transportation-approaching the limits of, and going beyond, lithium-ion
155
batteries, Energy Environ. Sci. 5 (7) (2012) 7854–7863. [3] Y. Zhao, A. Manthiram, Amorphous Sb2S3 embedded in graphite: a high-rate, long-life anode material for sodium-ion batteries, Chem. Commun. 51 (67) (2015) 13205–13208. [4] V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-Gonzalez, T. Rojo, Na-ion batteries, recent advances and present challenges to become low cost energy storage systems, Energy Environ. Sci. 5 (3) (2012) 5884–5901. [5] K. Chang, W. Chen, Single-layer MoS2/graphene dispersed in amorphous carbon: towards high electrochemical performances in rechargeable lithium ion batteries, J. Mater. Chem. 21 (43) (2011) 17175–17184. [6] W. Fang, H. Zhao, Y. Xie, J. Fang, J. Xu, Z. Chen, Facile hydrothermal synthesis of VS2/graphene nanocomposites with superior high-rate capability as lithiumion battery cathodes, ACS Appl. Mater. Interfaces 7 (23) (2015) 13044–13052. [7] H. Hou, M. Jing, Z. Huang, Y. Yang, Y. Zhang, J. Chen, Z. Wu, X. Ji, One-dimensional rod-like Sb2S3-based anode for high-performance sodium-ion batteries, ACS Appl. Mater. Interfaces 7 (34) (2015) 19362–19369. [8] Y. Wang, B. Qian, H. Li, L. Liu, L. Chen, H. Jiang, VSe2/graphene nanocomposites as anode materials for lithium-ion batteries, Mater. Lett. 141 (2015) 35–38. [9] Z. Zhang, X. Yang, Y. Fu, Nanostructured WSe2/C composites as anode materials for sodium-ion batteries, RSC Adv. 6 (16) (2016) 12726–12729. [10] M.S. Whittingham, The electrochemical characteristics of VSe2 in lithium cells, Mater. Res. Bull. 13 (9) (1978) 959–965. [11] L. Xiao, Y. Cao, J. Xiao, W. Wang, L. Kovarik, Z. Nie, J. Liu, High capacity, reversible alloying reactions in SnSb/C nanocomposites for Na-ion battery applications, Chem. Commun. 48 (27) (2012) 3321–3323. [12] Z. Zhang, X. Shi, X. Yang, Synthesis of core-shell NiSe/C nanospheres as anodes for lithium and sodium storage, Electrochim. Acta 208 (2016) 238–243. [13] H. Fan, H. Yu, X. Wu, Y. Zhang, Z. Luo, H. Wang, Y. Guo, S. Madhavi, Q. Yan, Controllable preparation of square nickel chalcogenide (NiS and NiSe2) nanoplates for superior Li/Na ion storage properties, ACS Appl. Mater. Interfaces 8 (38) (2016) 25261–25267.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Carbon-coated vanadium selenide as anode for lithium-ion batteries and sodium-ion batteries with enhanced electrochemical performance Xinhui Yang, Zhian Zhang n School of Metallurgy and Environment, Central South University, Changsha 410083, China
art ic l e i nf o
a b s t r a c t
Article history: Received 27 September 2016 Received in revised form 29 November 2016 Accepted 1 December 2016 Available online 2 December 2016
A Carbon-coated vanadium selenium composites were synthesized through a facile ball-milling method. The VSe2/C presents a structure that carbon layer covers around the pure VSe2 particles. The VSe2/C exhibits outstanding performances in electrochemical tests, showing an enhanced cycle capacities of 467 mA h g 1 for sodium-ion batteries and 453 mA h g 1 for lithium-ion batteries after 50 dischargecharge cycles. & 2016 Elsevier B.V. All rights reserved.
Keywords: Vanadium selenium Carbon-coating Ball-milling Lithium-ion batteries Sodium-ion batteries
1. Introduction
2. Experimental section
Nowadays lithium-ion batteries (LIBs) have been widely developed in electronic equipment, electric tools, electric vehicles, and power system [1,2]. Meanwhile, sodium-ion batteries (SIBs) are being recognized as an alternative to LIBs because of the elemental similarities between lithium and sodium and abundant sodium resources [3]. However, Na þ has a larger radius than Li þ , which makes it important for SIBs to find an appropriate anode material as replacement [4]. Two-dimensional transition metal dichalcogenides MX2 (M ¼ Mo, Ti, W, V, etc. X ¼S, Se) have shown excellent mechanical and electrochemical performances in many researches [5–9]. Vanadium selenide is a kind of MX2 crystals that has typical layered structure and lighter molecular mass than most MX2, which makes its theoretical capacity higher. As early as 1978, Whittingham et al. used VSe2 firstly in lithium cells [10]. In 2015 Li et al. synthesized VSe2/graphene nanocomposites as anode materials for LIBs [8]. Herein, VSe2/C composites synthesized by a facile ball-milling method are used as anode material for LIBs and SIBs for the first time. After further hybridize with Super P, a carbon layer is formed outside the VSe2 particles, which work as a conductive matrix as well as a buffer for volume change of VSe2 during Li þ and Na þ insertion and extraction [5,11]. The VSe2/C exhibits excellent electrochemical properties, making it an appropriate application for LIBs and SIBs.
The VSe2/C was synthesized by a ball-milling method. 0.5094g vanadium powder, 1.5792g selenium powder and Super P were placed into a planetary Ball Mill and react at the rate of 400 rpm for 8 h. The precursor was transferred into a tube furnace and heated in 600 °C for 3 h. For comparison, pure VSe2 was synthesized in the same way without the participation of Super P. Scanning electron microscopy (SEM, Nova NanoSEM 230), transmission electron microscopy (TEM, Tecnai G2 20ST), Powder X-ray diffraction (XRD, Rigaku3014) and thermogravimetric analysis (TGA, SDTQ600) were employed to character. Active material was mixed with Super P, sodium alginate at the ratio of 8:1:1 to prepare electrode. The CR2025 coin-type cells were assembled in argon-filled glove box. The electrolyte chosen for LIB was 1 M LiPF6 in ethylene carbonate/dimethyl carbonate/ diethyl carbonate (1:1:1 in volume) and for SIB was composed of 1 M NaClO4 in ethylene carbonate/diethyl carbonate (1:1 in volume) with another 5 wt% fluoroethylene carbonate. Lithium/sodium plate and Celgard 2400 were used as the counter electrode and separator respectively. Galvanostatic charge-discharge (LAND CT2001A) and cyclic voltammetry tests (PARSTAT 2273 electrochemical measurement system) were carry out to detect electrochemical properties of VSe2/C.
n
Corresponding author.
http://dx.doi.org/10.1016/j.matlet.2016.12.001 0167-577X/& 2016 Elsevier B.V. All rights reserved.
3. Result and discussion To figure out the accurate content of VSe2 in VSe2/C composites,
X. Yang, Z. Zhang / Materials Letters 189 (2017) 152–155
Fig. 1. (a) TGA curves of VSe2 and VSe2/C; (b) XRD patterns of VSe2 and VSe2/C.
Fig. 2. SEM and TEM images of VSe2 (a, b, c) and VSe2/C (d, e, f); Elemental mapping image of VSe2/C.
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X. Yang, Z. Zhang / Materials Letters 189 (2017) 152–155
TGA was conducted from room temperature to 800 °C under air atmosphere. As Fig. 1a shows, the weight loss of pure VSe2 and VSe2/C composites are respectively 53.01% and 60.07%. At first, both samples present a little weight increase between about 200 °C and 350 °C, which can be attributed to the oxidation of VSe2 and the formation of solid VO2 and SeO2[9,12]. After 350 °C, apparent weight loss appears in the curve of VSe2/C sample, because of the sublimation of SeO2 and complete oxidation of carbon matrix. Therefore, suppose that the weight loss of VSe2/C is equal to the sum weight loss of the pure VSe2 and the weight of its carbon layer. If we illustrate alpha ‘m’ to represent the total mass of VSe2/C composites, ‘n’ with the percentage composition of VSe2 in the VSe2/C composites, we can get an equation: 60.07% m ¼53.01% m n þm (1 n) [9]. Consequently, the VSe2 loading in VSe2/C composites is calculated to be 85%. The XRD was used to investigate the phase and crystal structure of samples. All the diffraction peaks of the VSe2 material and VSe2/C illustrated in Fig. 1b are perfectly marching with the standard VSe2 pattern (JCPDS card number: 89-1641), indicating that the synthesized samples are all highly purified and have typical crystal structure. However, there is no peak of carbon black observed in the patterns of VSe2/C. Combine with Raman pattern (Fig. S1), the carbon in composites exists in amorphous form. Fig. 2 shows the morphology images of VSe2 and VSe2/C. From Fig. 2a, the pure VSe2 appears to be some uneven agglomerates with a size of about several microns. VSe2/C particles become rough with white layers outside. Further detection through TEM illustrated in Fig. 2b and e have been conducted to confirm the structure that carbon covers around VSe2 particle. Fig. 2c shows only the orthometric VSe2 crystal lattice lines while Fig. 2f shows both the VSe2 and its covering amorphous carbon layer. Moreover, the energy dispersive X-ray spectroscopy (EDS) elemental mapping images of VSe2/C is shown in Fig. 2 demonstrates the elemental mapping image. V and Se scatters evenly in their pictures, while the carbon concentrates more on the edge of the certain particle. The carbon coat will can buffer the VSe2 from volume change (Fig. S2). The electrochemical performances of samples in SIBs are
demonstrated in Fig. 3. Fig. 3a describes their cycling performances. The discharge capacity of VSe2/C reaches 651 mA h g 1 initially, then decreases to 553 mA h g 1 in the second cycle with a relatively low Coulombic efficiency at 80%. Because that Na þ intercalate into VSe2 interlayer and a interphase between the solid/ electrolyte (SEI) forms [9]. After 50 discharge-charge cycles the VSe2/C contains a reversible capacity of 467 mA h g 1 without any marked loss and an efficiency approaching to 100%. For comparison, the VSe2 sample undergoes a sharply capacity decline and falls to 49 mA h g 1 after 50 cycles. The CV curves are displayed in Fig. 3b, which is parallel with most MX2. During discharge process, two reduction peaks at 1.4 V and 0.2 V arise in the first cycling that can be attribute to the insertion of Na þ , which generates the compound NaxVSe2 and NaxSe, and finally becomes Na2Se and V. On the other hand, oxidation peaks around 1.6 V and 2.2 V show up in charge process, which is mainly due to the extraction process of Na þ . Another reduction peak shows up at about 0.2 V due to the forming of SEI [13]. Fig. 3c shows the performances under different current densities from 50 to 2000 mA g 1. VSe2/C reversibly delivers the capacities of 437, 375, 326, 309, 263 and 132 mA h g 1, and efficiency is approaching to 100% at last. The lithium-storage properties are also illustrated in Fig. 3. The VSe2/C performs an initial discharge capacity as high as 592 mA h g 1. A sudden fall rises up in the second cycle blame for the Li þ intercalation into interlayer of VSe2 as well as irreversible reactions like decomposition of electrolyte. After 50 cycles, VSe2/C still holds a reversible capacity of 453 mA h g 1 while pure VSe2 fades very quickly to 54 mA h g 1 after 50 cycles. Fig. 3e presents the CV curves of VSe2/C. Two reduction peak at about 1.5 V can be observed in the first cycling that can be attribute to the insertion of Li þ . On the other hand, oxidation peaks around 1.8 V and 2.2 V appear in the initial cycle, which is mainly due to the extraction process of Li þ . Fig. 3f shows the capacity of the VSe2/C under different current densities from 100 to 4000 mA g 1, with the discharge capacities of 441, 429, 390, 308, 236 and 147 mA h g 1.
Fig. 3. Electrochemical performance of VSe2 and VSe2/C for SIBs (a, b, c) and LIBs (d, e, f). (a) Cycling performance at a current density of 100 mA g 1. (b) Cyclic voltammogram profiles of VSe2/C at a scan rate of 0.2 mV s 1. (c) Discharge capacity and efficiency of VSe2/C under different current densities. (d) Cycling performance at a current density of 200 mA g 1. (e) Cyclic voltammogram profiles of VSe2/C at a scan rate of 0.2 mV s 1. (f) Discharge capacity and efficiency of VSe2/C under different current densities.
X. Yang, Z. Zhang / Materials Letters 189 (2017) 152–155
4. Conclusion To conclude, a carbon-coated vanadium selenium composites were successfully synthesized through ball-milling method by commercial vanadium, selenium and Super P powder. The consequent VSe2/C was examined by some material characterizations and electrochemical tests, presenting a reversible capacities of 467 mA h g 1 for SIBs and 453 mA h g 1 for LIBs. Because of the high capacity and excellent cycle stability, as well as the facile production method, the VSe2/C composites are expected a promising anode material for both LIBs and SIBs.
Appendix A. Supplementary material Supplementary data associated with this article can be found in the online version at http://dx.doi.org/10.1016/j.matlet.2016.12. 001.
References [1] M. Armand, J.M. Tarascon, Building better batteries, Nature 451 (7179) (2008) 652–657. [2] M.M. Thackeray, C. Wolverton, E.D. Isaacs, Electrical energy storage for transportation-approaching the limits of, and going beyond, lithium-ion
155
batteries, Energy Environ. Sci. 5 (7) (2012) 7854–7863. [3] Y. Zhao, A. Manthiram, Amorphous Sb2S3 embedded in graphite: a high-rate, long-life anode material for sodium-ion batteries, Chem. Commun. 51 (67) (2015) 13205–13208. [4] V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-Gonzalez, T. Rojo, Na-ion batteries, recent advances and present challenges to become low cost energy storage systems, Energy Environ. Sci. 5 (3) (2012) 5884–5901. [5] K. Chang, W. Chen, Single-layer MoS2/graphene dispersed in amorphous carbon: towards high electrochemical performances in rechargeable lithium ion batteries, J. Mater. Chem. 21 (43) (2011) 17175–17184. [6] W. Fang, H. Zhao, Y. Xie, J. Fang, J. Xu, Z. Chen, Facile hydrothermal synthesis of VS2/graphene nanocomposites with superior high-rate capability as lithiumion battery cathodes, ACS Appl. Mater. Interfaces 7 (23) (2015) 13044–13052. [7] H. Hou, M. Jing, Z. Huang, Y. Yang, Y. Zhang, J. Chen, Z. Wu, X. Ji, One-dimensional rod-like Sb2S3-based anode for high-performance sodium-ion batteries, ACS Appl. Mater. Interfaces 7 (34) (2015) 19362–19369. [8] Y. Wang, B. Qian, H. Li, L. Liu, L. Chen, H. Jiang, VSe2/graphene nanocomposites as anode materials for lithium-ion batteries, Mater. Lett. 141 (2015) 35–38. [9] Z. Zhang, X. Yang, Y. Fu, Nanostructured WSe2/C composites as anode materials for sodium-ion batteries, RSC Adv. 6 (16) (2016) 12726–12729. [10] M.S. Whittingham, The electrochemical characteristics of VSe2 in lithium cells, Mater. Res. Bull. 13 (9) (1978) 959–965. [11] L. Xiao, Y. Cao, J. Xiao, W. Wang, L. Kovarik, Z. Nie, J. Liu, High capacity, reversible alloying reactions in SnSb/C nanocomposites for Na-ion battery applications, Chem. Commun. 48 (27) (2012) 3321–3323. [12] Z. Zhang, X. Shi, X. Yang, Synthesis of core-shell NiSe/C nanospheres as anodes for lithium and sodium storage, Electrochim. Acta 208 (2016) 238–243. [13] H. Fan, H. Yu, X. Wu, Y. Zhang, Z. Luo, H. Wang, Y. Guo, S. Madhavi, Q. Yan, Controllable preparation of square nickel chalcogenide (NiS and NiSe2) nanoplates for superior Li/Na ion storage properties, ACS Appl. Mater. Interfaces 8 (38) (2016) 25261–25267.