石 钏,李永亮,任祥忠,等.高性能锂电正极材料LiV3O8-MWCNTs的制备与性能[J].深圳大学学报理工版,2017,34(No.6(551-660)):551-556.[doi:10.3724/SP.J.1249.2017.06551]
Shi Chuan,Li Yongliang,Ren Xiangzhong,et al.Preparation and properties of LiV3O8-MWCNTs as high performance cathode materials for lithium-ion battery[J].Journal of Shenzhen University Science and Engineering,2017,34(No.6(551-660)):551-556.[doi:10.3724/SP.J.1249.2017.06551]
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高性能锂电正极材料LiV3O8-MWCNTs的制备与性能
石 钏,李永亮,任祥忠,邓立波,高 原,张培新

深圳大学化学与环境工程学院,广东深圳 518060

复合材料; 锂离子电池; 低温液相法; 钒酸锂; 多壁碳纳米管; 正极材料; 电化学性能

Preparation and properties of LiV3O8-MWCNTs as high performance cathode materials for lithium-ion battery
Shi Chuan, Li Yongliang, Ren Xiangzhong, Deng Libo, Gao Yuan, and Zhang Peixin

Shi Chuan, Li Yongliang, Ren Xiangzhong, Deng Libo, Gao Yuan, and Zhang PeixinCollege of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P.R.China

composite material; lithium-ion battery; low temperature liquid reaction; LiV3O8; multiwalled carbon nanotube(MWCNT); cathode materials; electrochemical performance

DOI: 10.3724/SP.J.1249.2017.06551

备注

利用低温液相法合成了钒酸锂-多壁碳纳米管(LiV3O8-(w)MWCNTs)(w分别为0、1%、2%、3%、4%和5%)复合正极材料.采用X-射线衍射(X-ray diffraction, XRD)和扫描电镜(scanning electron microscope, SEM)对复合材料的晶型和结构进行了表征. XRD分析结果表明,复合材料仍为单斜晶系; SEM图谱显示,LiV3O8材料附着在MWCNTs的网状结构上,且使颗粒细化; 通过恒流充放电测试、循环伏安(cyclic voltammetry, CV)及交流阻抗谱(electrochemical impedance spectroscopy, EIS)技术对材料的电化学性能进行了研究,结果表明,按LiV3O8质量百分比复合3% MWCNTs的LiV3O8-(3%)MWCNTs复合材料具有最佳的电化学性能,在0.1 C充放电倍率条件下,其首次放电比容量为364.5 mAh/g,循环50次后放电比容量仍有292.2 mAh/g,容量保持率为80.2%,而纯LiV3O8材料的首次放电比容量为308.2 mAh/g,循环50次后容量保持率仅为55.4%; 采用MWCNTs与LiV3O8复合可使锂离子在材料颗粒间的电荷转移阻抗变小,有利于Li+的嵌入和脱出.

Lithium trivanadate-multiwalled carbon nanotube(LiV3O8-(w) MWCNT)(w = 0, 1%, 2%, 3%, 4%, 5%)composite cathode materials are synthesized by low temperature liquid reaction. The crystal structures and microstructures are investigated by X-ray diffraction(XRD)and scanning electron microscope(SEM). XRD analyses show that the LiV3O8-(w) MWCNTs are still monoclinic. The SEM images show that the LiV3O8 is attached to the network structure of MWCNTs, and the LiV3O8 particles are refined. The electrochemical properties are also characterized with charge-discharge cycling performance, cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS). The results show that LiV3O8-(3%)MWCNTs have the best electrochemical properties when the mass percentage of MWCNTs is 3% in the composite, exhibiting a high discharge capacity of 364.5 mAh/g maintaining a stable capacity of 292.2 mAh/g within 50 cycles at the charge-discharge rate of 0.1 C, and having the capacity retention of 80.2%. However, in the pure LiV3O8, the discharge capacity is 308.2 mAh/g, and the capacity retention is only about 55.4% after 50 cycles. Finally, the EIS results show that the lithium-ion charge-transfer resistance decreases greatly when LiV3O8 is coated with NWCNTs, which is favorable for fast lithium-ion intercalations/deintercalations in the composite materials.

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