歧化
材料科学
多硫化物
催化作用
吸附
阴极
分离器(采油)
无机化学
硫黄
化学工程
物理化学
有机化学
化学
热力学
电解质
工程类
电极
物理
冶金
作者
Yongfeng Lin,Yecheng Zhou,Sheng Huang,Min Xiao,Dongmei Han,Jiaxiang Qin,Shuanjin Wang,Meng Ye
标识
DOI:10.1002/aenm.202201912
摘要
Abstract Addressing the lithium polysulfide shuttle is critical for the high‐energy‐density lithium–sulfur pouch cells in practical applications, especially under high sulfur loading and lean electrolyte conditions. In contrast to previously reported heterogeneous adsorption catalysis within cathode or separator with slow catalytic kinetics and limited adsorption area, herein, lithium difluorophosphate (LiPO 2 F 2 ) is demonstrated as a homogeneous catalyst in electrolyte which mitigates polysulfide diffusion. The Li–S pouch cell with LiPO 2 F 2 in the electrolyte has record‐breaking shelving stability of two months, significantly improved capacity retention from 37.0% to 81.4% after long cycling, and electrical‐car‐level energy density over 400 Wh kg −1 . A minimal amount of 1 wt% LiPO 2 F 2 tends to facilitate lithium polysulfide disproportionation on the S/C cathode instead of in the electrolyte, which initiates the fast transformation of soluble lithium polysulfide to insoluble solid S 8 and Li 2 S 2 /Li 2 S. The reliable mechanism of polysulfide disproportionation via biradicals is further proposed by both density functional theory calculation and experiments. To best of the authors’ knowledge, this is the first report on mechanism of polysulfide disproportionation via biradical intermediates. It is believed that this new insight into homogeneous catalytic mechanisms in electrolytes may pave the way for the commercialization of high‐energy‐density Li–S batteries.
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