Indium doped sulfide solid electrolyte with tamed lithium dendrite and improved ionic conductivity for all-solid-state battery applications

Sulfide solid state electrolytes capture much attention owing to their high conductivity and decent mechanical property. Nevertheless, the moisture instability and poor interfacial compatibility against lithium metal anode remain challenging and hinder the practical application. Herein, we report a novel indium (In) doping strategy based on the hard-soft-acid-base theory to tackle these issues. Optimized Li 7 P 2.9 S 10.9 In 0.1 electrolyte exhibits a high ionic conductivity of 4.1 × 10 −3  S cm −1 and achieves an enhanced interfacial compatibility. Importantly, as In partially replaces the phosphorus (P), the amount of released hydrogen sulfide can be significantly decreased and the air stability is improved. The all-solid-state battery assembled with the Li 7 P 2.9 S 10.9 In 0.1 electrolyte demonstrates a high discharge capacity and a good cycling stability under a high current density of 1.0 C. This work provides a practical and effective method to design sulfide-based solid-state electrolyte with high ionic conductivity and enhanced air stability for all-solid-state battery applications.