溶剂化
电解质
二甲氧基乙烷
化学
溶剂
硫黄
无机化学
锂(药物)
硫化物
钝化
物理化学
有机化学
电极
医学
内分泌学
图层(电子)
作者
Ning Zhong,Chengjun Lei,Ruijin Meng,Jinye Li,Xin He,Xiao Liang
出处
期刊:Small
[Wiley]
日期:2022-03-09
卷期号:18 (16)
被引量:45
标识
DOI:10.1002/smll.202200046
摘要
Passivation of the sulfur electrode by insulating lithium sulfide (Li2 S) restricts the reversibility and sulfur utilization of lithium-sulfur (Li-S) batteries. Although electrolytes with high donor number (DN) solvents induce tri-sulfur radical intermediate thus 3D nucleation of Li2 S with fast kinetics can be achieved, their catastrophic reactivities with Li metal hinder practical applications. Here, the use of high DN solvent as an additive instead of as co-solvent to solve their incompatibility between cathode and anode is proposed, by adopting N-methyl-2-pyrrolidone (NMP) as a proof-of-concept. Such a strategy is accomplished by the unique solvation structure of the NMP added electrolyte, where the preference of NMP-Li+ coordination squeezes out partial 1,2-dimethoxyethane (DME) molecules while enriching 1,3-dioxolane (DOL) molecules in the first solvation sheath of Li+ ions. It affords the robust SEI on Li metal from corrosion either by NMP or the dissolved polysulfides. Spectral analyses (Raman and UV-vis) also verify that the coordinated NMP additive preserves its S3•- radicals stabilization ability as it does as a co-solvent, which effectively improves the sulfur conversion kinetics and reversibility. This approach enables competitive capacity retention and a stable cycling performance of 340 cycles, which is one of the longest lifespans known for the high DN solvent involved Li-S batteries.
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