# Reconfigurable In–S Coordination in SPAN Cathodes: Unlocking High Sulfur Utilization and Fast Kinetics for Practical Li‒S Batteries

## TL;DR

A new method using indium-sulfur coordination in SPAN cathodes improves sulfur utilization and battery performance in lithium-sulfur batteries.

## Contribution

Introduces reconfigurable In–S coordination in SPAN to enhance sulfur utilization and kinetics in Li–S batteries.

## Key findings

- Reconfigurable In–S coordination increases active material content to 47.4 wt% with only 1.18 wt% indium.
- In5-SPAN cathodes achieve 1048 mAh·g−1 at 0.5 A g−1 under high sulfur loading and lean electrolyte.
- Outperforms existing SPAN cathodes in practical Li–S battery conditions.

## Abstract

Sulfurized polyacrylonitrile (SPAN) has emerged as a promising cathode material for high‐energy‐density lithium‒sulfur (Li‒S) batteries due to its ability to confine sulfur and suppress polysulfide shuttling. However, conventional SPAN suffers from sluggish conversion kinetics and limited sulfur utilization, especially at high sulfur loadings. In this work, reconfigurable indium‒sulfur (In–S) coordination into SPAN to dynamically regulate sulfur bonding states is introduced. The non‐crystalline In—S network reversibly anchors and releases sulfur during cycling, accelerating redox reactions while suppressing phase segregation. Structural analysis reveals atomically dispersed In—S coordination without crystalline inactive phases, achieving an active material content of 47.4 wt.% with only 1.18 wt.% indium addition (≈23% higher than conventional SPAN). Optimized In5‐SPAN cathodes deliver a high specific capacity of 1048 mAh·g−1 at 0.5 A g−1 under practical conditions of high SPAN mass loading (8.7 mg cm−2) and lean electrolyte (E/SPAN = 4.1). This performance surpasses state‐of‐the‐art SPAN‐based cathodes under comparable lean‐electrolyte and high‐loading conditions. These findings illustrate a novel reconfigurable metal‒sulfur coordination strategy for next‐generation Li‒S batteries with both high‐energy‐density and long cycle life.

An amorphous indium–sulfur complex is embedded in SPAN matrix to create reversible In–S coordination bonds that dynamically break and reform during cycling. This bond reconfiguration actively anchors intermediate polysulfides and accelerates sulfur conversion kinetics, providing simultaneously high active material utilization and durable cycling performance in lithium–sulfur batteries.