An encapsulating lithium-polysulfide electrolyte for practical lithium–sulfur batteries

• Published in: Chem Vol. 8; no. 4; pp. 1083 - 1098
• Main Authors: Hou, Li-Peng, Zhang, Xue-Qiang, Yao, Nan, Chen, Xiang, Li, Bo-Quan, Shi, Peng, Jin, Cheng-Bin, Huang, Jia-Qi, Zhang, Qiang
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 14.04.2022
• Subjects: di-isopropyl sulfide; encapsulating lithium polysulfide electrolyte; lithium–sulfur battery; solvation structure; solvent shell; encapsulating lithium polysulfide electrolyte; solvent shell; solvation structure; di-isopropyl sulfide; SDG7: Affordable and clean energy; lithium–sulfur battery
• ISSN: 2451-9294; 2451-9294
• DOI: 10.1016/j.chempr.2021.12.023

Practical lithium–sulfur batteries are severely hindered by parasitic reactions between lithium metal anodes and soluble lithium polysulfide (LiPS) intermediates. The solvation structure of LiPSs is pivotal in dictating the reaction kinetics. Herein, an encapsulating LiPS electrolyte (EPSE) is proposed to suppress parasitic reactions based on a nano-heterogeneous solvation structure design of LiPSs. In EPSE, with di-isopropyl sulfide (DIPS) as a co-solvent, soluble LiPSs are encapsulated into two concentric solvent shells with different solvating power and reduction stability. Reduction-stable DIPS in the outer solvent shell significantly suppresses the parasitic reactions between encapsulated LiPSs and lithium metal. A 1.2 Ah pouch cell under demanding conditions undergoes 103 cycles in the EPSE. This work provides two crucial criteria for constructing EPSE, that is, poor solvating power and high reduction stability of the solvent in outer solvent shell, and it opens up new frontiers in modulating the solvation structure of LiPSs toward long-cycling lithium–sulfur batteries. [Display omitted] •A nano-heterogeneous solvation structure of lithium polysulfides is investigated•An encapsulating LiPS electrolyte (EPSE) is designed for lithium–sulfur batteries•A 1.2 Ah pouch cell under demanding conditions undergoes 103 cycles in an EPSE•Two crucial criteria for constructing the EPSE are proposed The pursuit of a zero-carbon and wireless society necessitates the development of high-energy-density and long-cycling batteries as the power source for portable electronics, electric vehicles, and so on. The lithium–sulfur battery is a promising high-energy-density battery system. However, parasitic reactions between lithium metal anodes and soluble lithium polysulfide (LiPS) intermediates severely hinder the lifespans of practical lithium–sulfur batteries, and rational electrolyte design is imperative. Herein, an encapsulating LiPS electrolyte (EPSE) is designed based on an insightful understanding of the solvation structure of LiPSs, which mitigates the parasitic reaction kinetics and significantly improves the cycle life of practical lithium–sulfur batteries. This opens up new frontiers in electrolyte design toward long-cycling lithium–sulfur batteries. An encapsulating LiPS electrolyte (EPSE) is proposed for suppression of parasitic reactions based on a nano-heterogeneous solvation structure design of LiPSs. In the EPSE with di-isopropyl sulfide (DIPS) as a co-solvent, soluble LiPSs are encapsulated into two concentric solvent shells with different solvating power and reduction stability. Reduction-stable DIPS in the outer solvent shell significantly suppresses the parasitic reactions between encapsulated LiPSs and lithium metal. This work opens up new frontiers in electrolyte engineering toward long-cycling lithium–sulfur batteries.