Li-In-S composite foil with built-in electric fields to stabilize Li/Li<sub>6</sub>PS<sub>5</sub>Cl interface for long-life all-solid-state batteries.

Liu, Chong; Wang, Ruoyu; Wang, Dewen; Zhao, Liyun; Li, Taiguang; Wang, Tenghui; Chen, Butian; Zhang, Tianran et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Sulfides-based all-solid-state lithium batteries show great potential due to their high safety and high energy density, yet severely suffer from sulfide electrolytes/Li interfacial instability and short cycle life. Here we propose a Li-In-S composite foil comprising Li<sub>2</sub>S, Li<sub>x</sub>In, and LiInS<sub>2</sub> to stabilize the Li/Li<sub>6</sub>PS<sub>5</sub>Cl interface by constructing built-in electric fields, thereby enabling long-life all-solid-state lithium batteries. The work function difference between Li<sub>2</sub>S and Li<sub>x</sub>In generates built-in electric fields at the heterointerface, which traps the interfacial electrons and restricts their transfer to Li<sub>6</sub>PS<sub>5</sub>Cl, thereby suppressing the interfacial side reactions. Simultaneously, the built-in electric fields promote Li<sup>+</sup> adsorption and diffusion inhibiting lithium dendrite growth. Li symmetrical cells display high critical current density over 4 mA cm<sup>-2</sup> and Li plating/stripping stability over 2000 h at 1 mA cm<sup>-2</sup>. The assembled full cells with LiCoO<sub>2</sub> and LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub> (NCM811) demonstrate high capacity retention of 93% over 2000 cycles at 1 C and 87.7% over 1000 cycles at 1 C, respectively. Moreover, Li-In-S|Li<sub>6</sub>PS<sub>5</sub>Cl|NCM811 full cell shows rate capability up to 4 C. This work offers useful insights into the design of stable interfaces in all-solid-state batteries.