聚丙烯酸黏结剂的分子量对氧化亚硅负极性能的影响  

Effect of MolecularWeight of Polyacrylic Acid Binders on Properties of Silicon Suboxide Anode

作　　者：李剑 杨凯[2] 江秋月 雷晓华 郭庆中[1] 刘志宏 LI Jian;YANG Kai;JIANG Qiuyue;LEI Xiaohua;GUO Qingzhong;LIU Zhihong(School of Materials Science and Engineering,Wuhan Institute of Technology,Wuhan 430205,China;Key Laboratory of Optoelectronic Chemical Materials and Devices(Jianghan University),Ministry of Education,Wuhan 430056,China)

机构地区：[1]武汉工程大学材料科学与工程学院,湖北武汉430205 [2]光电化学材料与器件教育部重点实验室(江汉大学),湖北武汉430056

出　　处：《武汉工程大学学报》2023年第6期635-640,共6页Journal of Wuhan Institute of Technology

基　　金：国家自然科学基金(51872127,22139001);湖北省重点研发计划项目(2020BAA030)。

摘　　要：硅基负极材料因在嵌锂-脱锂过程中会产生剧烈的体积膨胀,限制了其在构建高能量密度锂离子电池中的应用。聚丙烯酸(PAA)作为一种高性能硅基负极黏结剂,倍受关注。采用不同黏均分子量的PAA黏结剂制备氧化亚硅电极,并测试了其溶胀性、力学性能和电化学性能。黏结剂PAA的黏均分子量为400万时,以0.4 A/g的电流密度循环100圈后,电池的容量保持率为88.4%,可逆比容量为1 017(mA·h)/g,高于黏均分子量为45万、125万的PAA黏结剂时的602(mA·h)/g和793.9(mA·h)/g的可逆比容量。结果表明:黏结剂PAA的分子量增大,其溶胀性能、弹性模量、硬度得到提升,抑制氧化亚硅负极膨胀的能力得到增强,有利于构建更稳固的固态电解质界面膜,从而提升氧化亚硅电极的循环倍率性能。The application of silicon-based anode materials for high energy density lithium-ion batteries is limited due to its huge volume expansion during the lithiation/delithiation process.Polyacrylic acid(PAA),as a high-performance silicon-based anode binder,has attracted much attention.Silicon suboxide electrodes were prepared by using PAA binders with different average molecular weights,and their swelling,mechanical and electrochemical properties were tested.When the viscosity-average molecular weight of PAA binder is 4 million,the capacity retention rate of the battery is 88.4%,and the reversible specific capacity is 1017(mA·h)/g at a current density of 0.4 A/g after 100 cycles,which is higher than the reversible specific capacity of 602 and 793.9(mA·h)/g when the viscosity-average molecular weights of the PAA binders are 4.5×105 and 1.25×106,respectively.The results show that the swelling property,elastic modulus and hardness of PAA are improved and the ability to inhibit expansion of silicon suboxide anode is strengthened with the increase of molecular weight of PAA,which is conducive to establishing more stable solid electrolyte interface layer and improving the cycle and rate performance of silicon suboxide anode.

关 键 词：氧化亚硅 负极材料 聚丙烯酸 黏结剂 

分 类 号：O646[理学—物理化学]