Tailoring the Periphery Aliphatic Group of Cathode Organosulfide for Rechargeable High-Performance All-Solid-State Lithium Battery

Abstract

Organic cathode materials exhibit higher energy storage capacity, their poor cyclability due to dissolution in liquid organic electrolytes remains a challenge. However, recently, the electrochemical behavior of organopolysulfides incorporating N-heterocycles unveils promising cathode materials with stable cycling performance. Herein, the integration of organosulfides salt as cathodes with solid electrolytes, exemplified by sodium allyl(methyl)carbamodithioate and sodium diethylcarbamodithioate with a polymer solid electrolyte of polyethylene oxide and LiTFSI, addresses the poor electrochemical stability of organic electrodes. Comparative analysis highlights sodium allyl(methyl)carbamodithioate's superior electrochemical performance and stability compared with sodium diethylcarbamodithioate, emphasizing the efficacy of periphery aliphatic modification in enhancing electrode capacity, rate performance, and electrochemical stability for organosulfide materials within all-solid-state lithium organic batteries. We also explore the origin of periphery aliphatic modification in these enhancing electrochemical performances by kinetic analysis and thermodynamic analysis. Furthermore, employing density functional theory calculations and ex situ FTIR experiments elucidates the critical role of the N–C=S structure in the energy storage mechanism. This research advances organic cathode design within organosulfide materials, unlocking the potential of all-solid-state lithium organic batteries with enhanced cyclability, propelling the development of next-generation energy storage systems.