一种基于Al_(2)O_(3)纳米纤维骨架的锂硫电池用凝胶聚合物电解质  

A gel polymer electrolyte with Al_(2)O_(3) nanofibers skeleton for lithium–sulfur batteries

作　　者：王慧敏 王振宇 周畅 李国然 刘胜 高学平 Hui-Min Wang;Zhen-Yu Wang;Chang Zhou;Guo-Ran Li;Sheng Liu;Xue-Ping Gao(Institute of New Energy Material Chemistry,School of Materials Science and Engineering,Nankai University,Tianjin 300350,China)

机构地区：[1]Institute of New Energy Material Chemistry,School of Materials Science and Engineering,Nankai University,Tianjin 300350,China

出　　处：《Science China Materials》2023年第3期913-922,共10页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(21935006,22075151,and 22279064);the Fundamental Research Funds for the Central Universities of China.

摘　　要：锂硫电池作为一种极具前景的二次电池系统受到了广泛关注.然而,传统液态电解质中多硫化锂的穿梭效应阻碍了其发展.在本工作中,我们制备了用于锂硫电池的功能性凝胶电解质.该电解质由聚偏氟乙烯-六氟丙烯(PVDF-HFP)和连续γ-Al_(2)O_(3)三维骨架组成.PVDF-HFP提供锂离子传输路径,使电解质具有良好的柔性;γ-Al_(2)O_(3)为路易斯酸,可通过与多硫化锂之间的路易斯酸碱相互作用抑制穿梭效应.而且,γ-Al_(2)O_(3)与路易斯碱TFSI-有相互作用,可促进锂盐解离,提高锂离子迁移数.此外,部分γ-Al_(2)O_(3)可以与LiF反应形成锂离子导体LiAlO_(2)和Li3AlF6来提高离子电导率.使用该凝胶电解质的锂硫电池在正极容量保持和负极形貌方面展现出良好的稳定性.该项研究为制备高能量锂硫电池的多功能凝胶电解质提供了一种有前景的策略.As a promising secondary battery system,lithium–sulfur (Li–S) batteries have attracted extensive attention due to their high energy density.However,the development of Li–S batteries is hindered by the detrimental shuttling of soluble lithium polysulfides (LiPs) in traditiona liquid electrolytes.In this work,we fabricate a functional ge polymer electrolyte for Li–S batteries.This electrolyte consists of poly(vinylidene fluoride-co-hexaflfluoropropylene)(PVDF-HFP) polymer matrix and a continuous γ-Al_(2)O_(3)three-dimensional skeleton with structural and thermal stability PVDF-HFP offers lithium-ion transport pathways and equips the electrolyte with flexibility,whereas the inorganic γ-Al_(2)O_(3)skeleton as Lewis acid can suppress the shuttling of LiPs through strong Lewis acid-base interactions between γ-Al_(2)O_(3)and LiPs.In addition,γ-Al_(2)O_(3)has an effect on the Lewis base of bis(trifluoromethanesulphony)imide anion,facilitating the dissociation of lithium salts and leading to a high lithium-ion transference number.Moreover,γ-Al_(2)O_(3)can improve the ionic conductivity by reacting with LiF to partly form the lithium-ion conductors of LiAlO_(2)and Li3AlF6.Benefiting from the synergistic effect of PVDF-HFP and γ-Al_(2)O_(3),Li–S cells with this gel polymer electrolyte present improved cycling stability in terms of cathode capacity retention and anode morphology.This work provides a promising strategy for fabricating multifunctional gel electrolytes for high-energy Li–S batteries.

关 键 词：锂硫电池 液态电解质 穿梭效应 锂离子导体 二次电池 锂离子迁移数 凝胶电解质 离子电导率 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ427.26[化学工程]