羧甲基纤维素-丁苯橡胶复合黏结剂在硅基锂离子电池中的应用
王信心,刘 健*,龚正良,甘礼惠,龙敏南

(厦门大学能源学院,福建 厦门 361102)

硅负极; 丁苯橡胶; 羧甲基纤维素; 黏结剂; 电化学性能

Application of Carboxymethyl Cellulose and Styrene-butadiene Rubber Binder in Silicon-based Lithium-ion Battery
WANG Xinxin,LIU Jian*,GONG Zhengliang,GAN Lihui,LONG Minnan

(College of Energy,Xiamen University,Xiamen 361102,China)

silicon anode; styrene-butadiene rubber(SBR); carboxymethyl cellulose(CMC); binder; electrochemical performance

DOI: 10.6043/j.issn.0438-0479.201803019

备注

黏结剂是影响锂离子电池性能的重要因素之一,将羧甲基纤维素(CMC)和丁苯橡胶(SBR)联合使用,有利于缓解锂离子电池电极的体积效应,但SBR的导电性较差不利于提升电池的电化学性能.为此,制备了不同取代度(0.23～0.86)的低聚合度CMC,并和4种高聚合度CMC分别应用于硅负极,进行循环性能的比较; 采用低聚合度CMC-SBR制备电极,进行电化学性能测试.结果表明,采用低聚合度CMC制备的电极的电化学性能优于高聚合度CMC,且不添加SBR时表现出相对优异的电化学性能,其中取代度为0.55的低聚合度CMC制备的电极循环性能最佳.因此,使用低聚合度CMC时不需添加SBR,既减少了用料成本,又节约了电池内部空间,有利于增加有效的电极材料.

Binder is one of the key materials that affect the electrochemical performance of lithium-ion batteries.Previous research has showed that the combined application of carboxymethyl cellulose(CMC)and styrene-butadiene rubber(SBR)in lithium-ion batteries contributes to reducing volume effect.The high elasticity of SBR is beneficial to the recovery of volume in the charge and discharge cycles,but SBR,occupying the inner space of the battery,is non-conductive and bad in terms of the electrochemical performance.In this study,CMC with low polymerization degree and different degrees of substitution(DS=0.23-0.86)was prepared,and together with 4 types of CMC with high polymerization degree were applied to silicon anode electrode,respectively,and the cycle performance was measured.And then,the CMC with low polymerization degree and SBR were jointly applied to silicon anode and subjected to electrochemical performance tests including galvanostatic discharge-charge,cyclic voltammetry,AC impedance and rate capability,while the experimental results showed that the electrochemical performance of the electrode prepared with CMC(DS=0.55)was the best,and those prepared using CMC with low polymerization degree were better than those of commercial CMC with high polymerization degree.The electrochemical performance of CMC-SBR electrode is inferior to those prepared with CMC alone.Therefore,it is not necessary to add SBR when preparing electrode using CMC with low polymerization degree,and absence of SBR can economize materials cost and save inner space of battery,thereby providing more space for effective electrode materials.