Robust Self-Standing Single-Ion Polymer Electrolytes Enabling High-Safety Magnesium Batteries at Elevated Temperature

Rechargeable magnesium batteries (RMBs) have great potential in the field of high-temperature specialized batteries owing to the superior thermostability and lower propensity for dendrite formation of Mg metal anodes. And the development of Mg2+-conducting electrolytes that can operate stably under elevated temperature conditions (>100 degrees C) is the key to high-temperature RMBs. Here, a robust self-standing single-ion polymer electrolyte (SSPE) enabling high-safety RMBs working at elevated temperature is presented. This SSPE exhibits an expanded electrochemical stability window of 4.8 V (vs Mg2+/Mg), a remarkable Mg2+-ion transference number of 0.79, and a highly reversible Mg plating/stripping performance. This rationally designed SSPE enables home-made Mo6S8//Mg batteries with superior high-temperature (up to 150 degrees C) performance and significantly improved safety characteristics under abuse conditions. This design concept for a robust SSPE provides a promising path to high-safety specialized RMBs operating at the elevated temperature, which also offers a new path for the development of functionalized electrolytes.