Cathode Engineering Enables Robust Interface Contact for High-Performance All-Sulfide-Based Li-SeS<sub>2</sub> Solid-State Batteries.

Xi, Lei; Li, Fangkun; Zhou, Xuanyi; Liang, Ziwei; Zeng, Jun; Chen, Jiahe; Sun, Zhaoyu; Gu, Tengteng et al. · ACS Nano · 2025

basic_science · Level V

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Abstract

All-solid-state Li-sulfur batteries are promising candidates for next-generation energy storage systems, owing to their high energy density and capability to address the safety concerns and electrochemical stability challenges (e.g., the shuttle effect) inherent to liquid-based batteries. However, the electronic insulating nature and limited reactivity of sulfur result in sluggish kinetics, low utilization, and restricted cathode mass loading. Herein, SeS<sub>2</sub> is proposed as a cathode active material due to its enhanced electronic conductivity compared to sulfur. SeS<sub>2</sub> composite cathodes prepared with varying composite strategies exhibited significant differences in the electrochemical performance. Benefiting from enhanced interaction at the three-phase interface, the ball-milled SeS<sub>2</sub>/Li<sub>6</sub>PS<sub>5</sub>Cl/Ketjen Black composite cathode (SeS<sub>2</sub>-BM@KB)-based cells delivered a reversible capacity of 673.5 mAh g<sup>-1</sup> after 300 cycles at 1 A g<sup>-1</sup> at 30 °C with a capacity retention of 80%. Furthermore, high loading cells achieved high areal capacities of up to 14.43 mAh cm<sup>-2</sup>. This study highlights the potential of SeS<sub>2</sub> as an outstanding cathode material for developing high-energy-density all-solid-state batteries (ASSBs).