龚露露,罗国旗,姚 俊,等.高性能硅铜合金负极材料的制备及性能研究[J].深圳大学学报理工版,2021,38(3):272-279.[doi:10.3724/SP.J.1249.2021.03272]
GONG Lulu,LUO Guoqi,YAO Jun,et al.Preparation and electrochemical properties of silicon copper alloy for high performance anode[J].Journal of Shenzhen University Science and Engineering,2021,38(3):272-279.[doi:10.3724/SP.J.1249.2021.03272]
点击复制
高性能硅铜合金负极材料的制备及性能研究
龚露露1,罗国旗2,姚 俊1,尹小龙3,陈焕辉3,任祥忠3

1)湖北航天化学技术研究所,湖北襄阳441003; 2)襄阳三沃航天薄膜材料有限公司,湖北襄阳441003; 3)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; Si-Cu材料; N掺杂碳材料; 负极材料; 电化学性能

Preparation and electrochemical properties of silicon copper alloy for high performance anode
GONG Lulu1, LUO Guoqi2, YAO Jun1, YIN Xiaolong3, CHEN Huanhui3, and REN Xiangzhong3

1)Hubei Institute of Aerospace Chemical Technology, Xiangyang 441003, Hubei Province, P.R.China;2)Xiangyang Sunvalor Aerospace Films Co. Ltd., Xiangyang 441003, Hubei Province, P.R.China;3)College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P.R.China

composite material; lithium-ion batteries; Si-Cu materials; N-doped carbon materials; anode materials; electrochemical performance

DOI: 10.3724/SP.J.1249.2021.03272

备注

为提高锂离子电池硅基负极材料的电化学性能,采用化学还原及机械球磨法制备硅-铜(Si-Cu)不相容合金负极材料,并以苯胺为单体对Si-Cu材料进行原位聚合,经高温煅烧得到氮掺杂碳包覆的Si-Cu合金(Si-Cu/N-C)复合负极材料. 利用X-射线衍射、 扫描电子显微镜和透射电子显微镜(transmission electron microscopy, TEM)对材料的结构形貌进行表征,通过恒流充放电、循环伏安和电化学交流阻抗等分析测试技术,研究了材料的电化学性能. 研究结果表明,当Si:Cu质量比为 1.5:1,球磨时间为7 h时,首次放电比容量高达1 018.6 mAh/g,100次充放电循环后放电比容量为499.2 mAh/g,显示出最佳的电化学性能和稳定性. 经过包覆改性后,TEM显示该复合负极材料具有核-壳结构. 当加入的苯胺单体为0.45 mL时,复合负极材料的首次放电比容量为1 147.7 mAh/g,100次充放电循环后,放电比容量为857.9 mAh/g,与改性前的Si-Cu负极材料相比,容量保持率提高了10.8%. 改性后电化学性能的提升归因于复合负极材料独特的核-壳结构,聚苯胺高温碳化后得到的N掺杂碳包覆层不仅提高了复合负极材料的导电性,而且减少了材料间的接触阻抗. 此外,氮元素掺杂碳的Si-Cu/N-C 复合负极材料表面活性点增加,使得嵌脱锂电位平台降低,同时在循环过程中有利于形成稳定的固体电解质膜.
To improve the electrochemical performance of silicon-based anode materials, herein, silicon-copper(Si-Cu)incompatible alloy anode material were prepared via facile chemical reduction and ball milling methods. Subsequently, nitrogen-doped carbon-coated Si-Cu alloy(Si-Cu/N-C)composites were prepared via in-situ polymerization with aniline in the high-temperature calcinations process. X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM)were performed to analyze the physical characterization of these materials. Besides, the electrochemical performance of the catalysis was studied by constant current charging and discharging, cyclic voltammetry and electrochemical AC impedance spectroscopy(EIS). Electrochemical tests demonstrate that Si-Cu anode performs a high electrocatalytic activity when the ratio of Si to Cu is 1.5:1 and the ball milling time is 7 h. The anode exhibits an initial discharge capacity of 1 018.6 mAh/g and a capacity of 499.2 mAh/g after 100 cycles. After the coating modification, TEM result shows that this composite anode material possesses a core-shell structure. When the coating mass of N-doped carbon is 0.45, the Si-Cu/N-C electrode exhibits an initial discharge capacity of 1 147.7 mAh/g and maintains a specific capacity of 857.9 mAh/g after 100 cycles. Furthermore, the capacity retention rate of Si-Cu/N-C anode increases by 10.8% as compared with that of Si-Cu. The improved electrochemical performance after modification is attributed to the unique core-shell structure of Si-Cu/N-C. On the one hand, the N-doped carbon coating layer not only improves the conductivity, but also reduces the contact resistance between the electrolyte and electrode. On the other hand, the nitrogen doping of Si-Cu/N-C composite can increase the active site of lithium storage on the surface, reduce lithium storage potential and form a stable solid electrolyte interface(SEI)film during the cycling process.
·