本征型阻燃凝胶聚合物电解质的设计及其锂离子电池性能研究  

Design of intrinsically flame-retardant gel polymer electrolytes for lithium-ion batteries

作　　者：王晨蕾 阚永春 桂宙[1] WANG Chenlei;KAN Yongchun;GUI Zhou(State Key Laboratory of Fire Science,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学技术大学火灾科学国家重点实验室,合肥230026

出　　处：《火灾科学(中英文)》2024年第4期233-242,共10页Fire Safety Science

基　　金：中央高校基本科研业务费(WK2320000057)。

摘　　要：为解决传统聚丙烯酸酯凝胶电解质易燃且无法有效阻止电池热失控的问题,以合成的含磷酸酯结构的交联剂取代原有的含醚交联剂,通过原位自由基聚合的方式制备了阻燃聚丙烯酸酯凝胶电解质。相比未改性的凝胶电解质,阻燃凝胶电解质的电化学性能和阻燃性能得到大幅度提升。离子电导率从2.4×10^(-4) S/cm提升到4.6×10^(-4) S/cm,电化学稳定窗口从4.3 V提升到4.7 V。基于阻燃凝胶电解质的Li//NCM811半电池在4.3 V、0.5 C下循环的首圈放电比容量为165.7 mAh·g^(-1),明显高于改性前的134.3 mAh·g^(-1),循环200圈后的容量保留率从64%提升到68.4%;基于阻燃凝胶电解质的Li//LFP半电池在4.2 V、1 C下循环280圈后的容量保留率从84.3%提升到91.2%,且在2 C倍率下的充放电平台电压差从0.31 V降低到0.21 V。另外,改性后的阻燃凝胶电解质在燃烧测试中能够实现1 s内离火自熄,且具有优异的成炭性能。通过将磷酸酯结构引入凝胶电解质的聚合物骨架中,实现了锂离子电池的电化学性能和防火安全性的同步提升,拓展了其应用范围和潜力。In order to solve the problem of flammability and poor safety of traditional polyacrylate gel electrolyte,a flame-retardant polyacrylate gel electrolyte was prepared by replacing the original ether-containing crosslinker(TEGDMA) with a synthetic phosphate-containing structure crosslinker(PDMA).The initial discharge specific capacity of the Li//NCM811 half-cell containing the flame-retardant electrolyte was 165.7 mAh·g^(-1) at 4.3 V and 0.5 C,significantly higher than the 134.3 mAh·g^(-1) before modification.After 200 cycles,the capacity retention rate increased from 64% to 68.4%.For the Li//LFP half-cell based on the flame-retardant gel electrolyte,the capacity retention rate increased from 84.3% to 91.2% after 280 cycles at 4.2 V and 1 C,the voltage difference of the charge-discharge plateau at a rate of 2 C decreased from 0.31 V to 0.21 V.In addition,the modified flame retardant gel electrolyte could achieve self-extinguishing within 1 s in the combustion test,and had excellent charring performance.The electrochemical performance and fire safety of lithium-ion batteries were improved by introducing the phosphate ester structure into the polymer backbone of the gel electrolyte.

关 键 词：锂离子电池 凝胶电解质 磷酸酯 阻燃 

分 类 号：X915.5[环境科学与工程—安全科学]