2,5-Dimercapto-1,3,4-thiadiazole-modified gel electrolyte for reduced shuttle effect and enhanced redox kinetics of lithium–sulfur batteries

TL;DR

A new gel electrolyte for lithium-sulfur batteries improves safety and performance by reducing the shuttle effect and boosting redox reactions.

Contribution

A novel PVDF gel electrolyte with 2,5-dimercapto-1,3,4-thiadiazole is introduced to suppress the shuttle effect and enhance redox kinetics.

Findings

The Li–S battery retains 180.5 mA h g−1 at 1C, outperforming control cells.

At 0.5C, it shows an ultralow decay rate of 0.13% per cycle and 99% coulombic efficiency.

The strategy improves rate performance and cycling stability in Li–S batteries.

Abstract

The safety risks of liquid electrolyte leakage in conventional batteries have prompted intensive research on solid electrolytes for enhanced safety and energy density. Here, we report a novel PVDF gel electrolyte (GE) by incorporating 2,5-dimercapto-1,3,4-thiadiazole (DMcT). By virtue of the active thiol groups (S–H), DMcT can function as a difunctional mediator to suppress the shuttle effect and accelerate the redox kinetics of Li–S batteries, thereby enabling boosted rate performances and enhanced cycling stability of Li–S batteries. At 1C, the Li–S battery retains 180.5 mA h g−1, outperforming control cells. At 0.5C, it exhibits an ultralow decay rate (0.13% per cycle) with 99% coulombic efficiency. This work presents a novel strategy to address the shuttle effect and improve the rate performance in gel electrolyte Li–S batteries, paving the way for safer high-energy battery systems.

A difunctional mediator is incorporated into a PVDF GE to suppress the shuttle effect and ac, celerate the redox kinetics of Li–S batteries.

Figures