From Irreversible to Reversible: Nucleophilic Reactions Enhance Fast Kinetics and Superior Cycling Stability in High Voltage Lithium-Organosulfur Batteries.

Abstract

Organosulfur represents a class of promising candidates as cathode materials for rechargeable batteries. However, their development has been hindered by several key factors, including low discharge voltage, shuttle of polysulfides, and sluggish kinetics. Herein, tetramethylthiuram monosulfide (TMTM) is introduced as a functional substrate and composited with diphenyl tetrasulfide (PTS), which is denoted as PT14. During discharge, PTS generates benzenethiolate and sulfide anions, both of which can in situ react with TMTM forming new electrochemical reactive species. This design mitigates the polysulfide shuttle effect and enables rapid reaction kinetics. The Li-PT14 cell shows a high discharge voltage of 2.55 V and retains 90% of the initial capacity after 700 cycles at a 1C rate. When the temperature is increased to 60 °C, the cell retains 95% of the initial capacity after 500 cycles. When paired with a lithiated carbon paper anode (LiC) to form a full cell, it delivers a capacity retention of 97% after 840 cycles at N/P = 3.5 and 0.5 C rate. Furthermore, a 100 mAh pouch cell assembled with the PT14 cathode shows no capacity loss after 50 cycles. This work provides a new strategy to develop advanced rechargeable batteries based on organosulfur cathode materials.