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N-doped hollow carbon nanospheres as sulfur hosts for high performance Li-S batteries
Carbon 124 (2017) 728e730
Contents lists available at ScienceDirect
Carbon journal homepage: www.elsevier.com/locate/carbon
New Carbon Materials Abstracts 2017(4) [New Carbon Materials 2017, 32(4): 289-296] A ONE-STEP HARD-TEMPLATING METHOD FOR THE PREPARATION OF A HIERARCHICAL MICROPOROUS-MESOPOROUS CARBON FOR LITHIUMSULFUR BATTERIES Shu-zhang Niu a, b, Si-da Wu a, Wei Lu a, Quan-hong Yang a, Fei-yu Kang a, b. a Engineering Laboratory for Functionalized Carbon Materials, Graduate School at Shen Zhen, Tsinghua University, Shenzhen, 518055, China; b Laboratory of Advanced Materials, School of Materials, Tsinghua University, Beijing, 100084, China Abstract: Porous carbon materials can increase the conductivity of sulfur and restrain the shuttling of polysulfides in the electrolyte. A hierarchical microporous-mesoporous carbon (HMMC) with a large surface area and pore volume was prepared by the simple one-step carbonization of a mixture of magnesium gluconate (MG) and phenolic resin. The MG was transformed into nanosize magnesium oxide that acted as a hard template during carbonization to create mesopores. The HMMC has a high surface area (~1 560 m2 g-1) and large pore volume (~2.6 cm3 g-1), which provides abundant space for sulfur loading and accommodates volume changes during charge/discharge. The interconnected pore structure and carbon framework ensure fast electron and Li ion transfer. As the cathode of a Li-S battery the sulfur-loaded HMMC has a high discharge capacity of 939 mAh g-1 at 0.3 C and a reversible capacity of 731 mAh g-1 after 150 cycles with only a 0.15% capacity fade per cycle. Even at a high rate of 2 C, it still delivers a high discharge capacity of 626 mAh g-1, showing an excellent rate performance. [New Carbon Materials 2017, 32(4): 297-303] N-DOPED HOLLOW CARBON NANOSPHERES AS SULFUR HOSTS FOR HIGH PERFORMANCE Li-S BATTERIES Yong-zheng Zhang a, Li-xin Ding a, Liang Zhan a, Yan-li Wang a, Yan Song b. a State Key Laboratory of Chemical Engineering, Key Laboratory for Specially Functional Polymers and Related Technology of Ministry of Education, Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China; b CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China Abstract: SiO2@C nanospheres were fabricated by polymerization of dopamine in the presence of tetraethyl orthosilicate followed by carbonization and the SiO2 was chemically etched away to obtain hollow N-doped carbon nanospheres (N-CNs) to host sulfur. The resulting material (S@N-CNs) was used as the cathode material of a Li-S battery. Results indicate that the S@N-CNs can effectively suppress the volume expansion of sulfur and the shuttle effect of polysulfides during charge and discharge. Nitrogen doping improves the electrical conductivity of the N-CNs. The initial reversible capacity of the S@N-CN electrode at 0.2 C is 1179 mA h g-1, which remains at 540 mA h g-1 after 100 cycles. The electrode has excellent rate capability (343 mA h g-1 at 1 C and 247 mA h g-1 at 2 C).
[New Carbon Materials 2017, 32(4): 304-310] PREPARATION AND ELECTROCHEMICAL PROPERTIES OF NaF-Si-C-RGO HYBRIDS Xiao Li a, b, Yan Song b, Xiao-dong Tian a, b, Kai Wang a, b, Quan-gui Guo b, Lang Liu b, Cheng-meng Chen b. a University of Chinese Academy of Sciences, Beijing, 100049, China; b Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China Abstract: NaF and Si nanoparticles and graphite oxide (GO) flakes were dispersed in a thermosetting phenolic resin (PR) in an aqueous solution, followed by drying and carbonization at 700 oC to produce NaF-Si-C-RGO hybrids. The structure of the hybrids was characterized by SEM, TEM, TGA, XRD and Raman spectroscopy. The electrochemical properties of the hybrids as anode materials of lithium ion battery were investigated and showed better electrochemical performance, larger reversible capacity and higher capacity retention when compared with both NaF-Si-RGO and Si-CRGO hybrids. The amorphous carbon coating on the Si nanoparticles, derived from the PR, restricts the formation of a solid-electrolyte interface film. The Na+ in NaF is inserted between the GO layers, which not only alleviates the re-stacking of graphene sheets, but also improves the dispersion of Si nanoparticles in RGO layers, leading to a high utilization of active materials. F- also inhibits the decomposition of the electrolyte and the generation of HF, which is favorable for the cycle stability of the electrode.
[New Carbon Materials 2017, 32(4): 311-318] SYNTHESIS OF SiO2@CARBON-GRAPHENE MATERIALS OF LITHIUM-ION BATTERIES
HYBRIDS
AS
ANODE
Ling-hong Yin, Ming-bo Wu, Yan-peng Li, Gui-liang Wu, Yuan-kun Wang, Yang Wang. State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, University of Petroleum, Qingdao, 266580, China Abstract: SiO2@carbon-graphene (SiO2@C-G) hybrids with excellent electrochemical performance were prepared by the self-assembly of colloidal silica, sucrose and graphene oxide followed by ultrasonic-assisted hydrothermal and heat treatments. The mass ratio of silica to sucrose is crucial to the electrochemical performance of the resulting hybrids. A hybrid with a mass ratio of silica to sucrose of 0.15 shows the best reversible lithium storage performance, delivering an initial discharge capacity of 906 mAh g-1 and a capacity of 542 mAh g-1 at the 216th cycle at a current density of 100 mA g-1. The excellent cycling ability and high reversible capacity are attributed to a synergetic effect of the good conductivity of the SiO2@C-G hybrids, the small SiO2 particle size and the good dispersion of SiO2 nanoparticles in the hybrids. This methodology may provide a simple, scalable and eco-friendly strategy to prepare superior electrode materials from cheap and low electrical conductivity metal oxides.
Contents lists available at ScienceDirect
Carbon journal homepage: www.elsevier.com/locate/carbon
New Carbon Materials Abstracts 2017(4) [New Carbon Materials 2017, 32(4): 289-296] A ONE-STEP HARD-TEMPLATING METHOD FOR THE PREPARATION OF A HIERARCHICAL MICROPOROUS-MESOPOROUS CARBON FOR LITHIUMSULFUR BATTERIES Shu-zhang Niu a, b, Si-da Wu a, Wei Lu a, Quan-hong Yang a, Fei-yu Kang a, b. a Engineering Laboratory for Functionalized Carbon Materials, Graduate School at Shen Zhen, Tsinghua University, Shenzhen, 518055, China; b Laboratory of Advanced Materials, School of Materials, Tsinghua University, Beijing, 100084, China Abstract: Porous carbon materials can increase the conductivity of sulfur and restrain the shuttling of polysulfides in the electrolyte. A hierarchical microporous-mesoporous carbon (HMMC) with a large surface area and pore volume was prepared by the simple one-step carbonization of a mixture of magnesium gluconate (MG) and phenolic resin. The MG was transformed into nanosize magnesium oxide that acted as a hard template during carbonization to create mesopores. The HMMC has a high surface area (~1 560 m2 g-1) and large pore volume (~2.6 cm3 g-1), which provides abundant space for sulfur loading and accommodates volume changes during charge/discharge. The interconnected pore structure and carbon framework ensure fast electron and Li ion transfer. As the cathode of a Li-S battery the sulfur-loaded HMMC has a high discharge capacity of 939 mAh g-1 at 0.3 C and a reversible capacity of 731 mAh g-1 after 150 cycles with only a 0.15% capacity fade per cycle. Even at a high rate of 2 C, it still delivers a high discharge capacity of 626 mAh g-1, showing an excellent rate performance. [New Carbon Materials 2017, 32(4): 297-303] N-DOPED HOLLOW CARBON NANOSPHERES AS SULFUR HOSTS FOR HIGH PERFORMANCE Li-S BATTERIES Yong-zheng Zhang a, Li-xin Ding a, Liang Zhan a, Yan-li Wang a, Yan Song b. a State Key Laboratory of Chemical Engineering, Key Laboratory for Specially Functional Polymers and Related Technology of Ministry of Education, Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China; b CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China Abstract: SiO2@C nanospheres were fabricated by polymerization of dopamine in the presence of tetraethyl orthosilicate followed by carbonization and the SiO2 was chemically etched away to obtain hollow N-doped carbon nanospheres (N-CNs) to host sulfur. The resulting material (S@N-CNs) was used as the cathode material of a Li-S battery. Results indicate that the S@N-CNs can effectively suppress the volume expansion of sulfur and the shuttle effect of polysulfides during charge and discharge. Nitrogen doping improves the electrical conductivity of the N-CNs. The initial reversible capacity of the S@N-CN electrode at 0.2 C is 1179 mA h g-1, which remains at 540 mA h g-1 after 100 cycles. The electrode has excellent rate capability (343 mA h g-1 at 1 C and 247 mA h g-1 at 2 C).
[New Carbon Materials 2017, 32(4): 304-310] PREPARATION AND ELECTROCHEMICAL PROPERTIES OF NaF-Si-C-RGO HYBRIDS Xiao Li a, b, Yan Song b, Xiao-dong Tian a, b, Kai Wang a, b, Quan-gui Guo b, Lang Liu b, Cheng-meng Chen b. a University of Chinese Academy of Sciences, Beijing, 100049, China; b Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China Abstract: NaF and Si nanoparticles and graphite oxide (GO) flakes were dispersed in a thermosetting phenolic resin (PR) in an aqueous solution, followed by drying and carbonization at 700 oC to produce NaF-Si-C-RGO hybrids. The structure of the hybrids was characterized by SEM, TEM, TGA, XRD and Raman spectroscopy. The electrochemical properties of the hybrids as anode materials of lithium ion battery were investigated and showed better electrochemical performance, larger reversible capacity and higher capacity retention when compared with both NaF-Si-RGO and Si-CRGO hybrids. The amorphous carbon coating on the Si nanoparticles, derived from the PR, restricts the formation of a solid-electrolyte interface film. The Na+ in NaF is inserted between the GO layers, which not only alleviates the re-stacking of graphene sheets, but also improves the dispersion of Si nanoparticles in RGO layers, leading to a high utilization of active materials. F- also inhibits the decomposition of the electrolyte and the generation of HF, which is favorable for the cycle stability of the electrode.
[New Carbon Materials 2017, 32(4): 311-318] SYNTHESIS OF SiO2@CARBON-GRAPHENE MATERIALS OF LITHIUM-ION BATTERIES
HYBRIDS
AS
ANODE
Ling-hong Yin, Ming-bo Wu, Yan-peng Li, Gui-liang Wu, Yuan-kun Wang, Yang Wang. State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, University of Petroleum, Qingdao, 266580, China Abstract: SiO2@carbon-graphene (SiO2@C-G) hybrids with excellent electrochemical performance were prepared by the self-assembly of colloidal silica, sucrose and graphene oxide followed by ultrasonic-assisted hydrothermal and heat treatments. The mass ratio of silica to sucrose is crucial to the electrochemical performance of the resulting hybrids. A hybrid with a mass ratio of silica to sucrose of 0.15 shows the best reversible lithium storage performance, delivering an initial discharge capacity of 906 mAh g-1 and a capacity of 542 mAh g-1 at the 216th cycle at a current density of 100 mA g-1. The excellent cycling ability and high reversible capacity are attributed to a synergetic effect of the good conductivity of the SiO2@C-G hybrids, the small SiO2 particle size and the good dispersion of SiO2 nanoparticles in the hybrids. This methodology may provide a simple, scalable and eco-friendly strategy to prepare superior electrode materials from cheap and low electrical conductivity metal oxides.