聚乙烯亚胺/聚丙烯酰胺复合交联型水性粘结剂在锂离子电池Si/C负极中的应用  

Polyethyleneimine/Polyacrylamide Composite as Cross-linkable Aqueous Binder for Si/C Anodes of Lithium-ion Batteries

作　　者：邓攀 陈程 张灵志[1] Pan Deng;Cheng Chen;Ling-zhi Zhang(Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,CAS Key Laboratory of Renewable Energy,Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development,Guangzhou 510640;Nano Science and Technology Institute,University of Science and Technology of China,Suzhou 215123)

机构地区：[1]中国科学院广州能源研究所,中国科学院可再生能源重点实验室,广东省新能源和可再生能源研究开发与应用重点实验室,广州510640 [2]中国科学技术大学纳米科学技术学院,苏州215123

出　　处：《高分子学报》2021年第11期1473-1480,共8页Acta Polymerica Sinica

基　　金：国家自然科学基金项目(基金号21573239,51602312);广东省特殊支持计划(项目号2014TX01N014)资助项目.

摘　　要：高比容量Si/C负极材料在充/放电循环过程中,由于硅的体积膨胀效应,极易引起电极材料的粉碎和脱落进而导致电池容量衰减和循环寿命缩短,开发新型Si/C负极粘结剂是提高电池循环性能的有效途径之一.通过对支化聚乙烯亚胺(BPEI)与聚丙烯酰胺(PAM)进行原位热交联制备三维互穿网状聚合物水性粘结剂(BPEI-PAM),并用于高比能锂离子电池Si/C负极的电化学性能研究.用TGA、DSC对复合粘结剂进行了热性能表征,利用FTIR进行结构表征.与商用水性粘结剂羧甲基纤维素/丁苯橡胶(CMC/SBR)作比较,研究BPEI-PAM电极的电化学性能.当BPEI与PAM原位热交联反应摩尔比为1∶6时,制备的Si/C极片剥离强度达0.82 N/cm,高于CMC/SBR(0.32 N/cm).提高极片的负载量至3.0 mg/cm^(2)时,200次循环后容量保持率为81.2%,优于CMC/SBR(76.1%).研究结果表明,通过交联制备的BPEI-PAM粘结剂具有更高的粘结性能,能明显提高Si/C电极的电化学性能.High-capacity Si/C anodes face the huge volume change during Li insertion/extraction process,which consequently leads to the pulverization of the silicon and eventually capacity fading and poor cycle life of lithium ion batteries.To tackle this issue,new binder materials is extensively explored to improve the cycle life by effectively alleviating the huge volume change,and thus improving the cycling life.In this work,a new cross linkable aqueous composite binder based on branched polyethyleneimine and polyacrylamide(BPEI-PAM)for Si/C anodes is reported.TGA,DSC,FTIR measurements are performed to characterize the crosslinking reaction of BPEI and PAM and their thermal properties.The electrochemical performances of the Si anodes with BPEI-PAM new binder are investigated and compared with the conventional aqueous binder of carboxymethyl cellulose/styrene butadiene rubber(CMC/SBR).By using the optimized BPEI-PAM binder(1:6 in molar ratio),the Si/C electrode exhibits the higher peel strength of 0.82 N/cm as compared with 0.32 N/cm for CMC/SBR.Even at a high loading of 3.0 mg/cm^(2),the Si/C electrode with BPEI-PAM can still maintain 81.3%capacity retention after 200 cycles,better than 76.1%for the electrode with CMC/SBR.This improved electrochemical performances can be attributed to the higher adhesion property of BPEI-PAM binder after crosslinking during the process of Si/C electrodes.

关 键 词：锂离子电池 Si/C负极 水性粘结剂 

分 类 号：TQ430.7[化学工程] TM912[电气工程—电力电子与电力传动]