Solid-State Lithium–Sulfur Batteries Operated at 37 °C with Composites of Nanostructured Li₇La₃Zr₂O₁₂/Carbon Foam and Polymer

An all solid-state lithium-ion battery with high energy density and high safety is a promising solution for a next-generation energy storage system. High interface resistance of the electrodes and poor ion conductivity of solid-state electrolytes are two main challenges for solid-state batteries, which require operation at elevated temperatures of 60-90 °C. Herein, we report the facile synthesis of Al³⁺/Nb⁵⁺ codoped cubic Li₇La₃Zr₂O₁₂ (LLZO) nanoparticles and LLZO nanoparticle-decorated porous carbon foam (LLZO@C) by the one-step Pechini sol-gel method. The LLZO nanoparticle-filled poly(ethylene oxide) electrolyte shows improved conductivity compared with filler-free samples. The sulfur composite cathode based on LLZO@C can deliver an attractive specific capacity of >900 mAh g⁻¹ at the human body temperature 37 °C and a high capacity of 1210 and 1556 mAh g⁻¹ at 50 and 70 °C, respectively. In addition, the solid-state Li-S batteries exhibit high Coulombic efficiency and show remarkably stable cycling performance.