Medium‐Concentration Electrolytes Balance Hydrogen‐Bond Disruption and Ion–Ion Interactions for Wide‐Temperature Aqueous Trivalent Indium Metal Batteries

It is desirable to develop aqueous batteries that can operate efficiently across wide temperature ranges; however, it remains a grand challenge to simultaneously suppress electrolyte freezing at low temperatures and water‐induced side reactions at elevated temperatures. Herein, we demonstrate that a medium‐concentration chloride electrolyte can effectively regulate the electrolyte solvation structures, leading to high‐efficiency and wide‐temperature aqueous trivalent indium metal batteries. Specifically, the increment of salt concentration progressively disrupts the hydrogen‐bonding network of water and reconstructs the In 3+ solvation structure toward chloride‐rich complexes, achieving a balanced effect at the medium concentration (10 m) of the studied range (5, 10, and 15 m). The optimized 1 m InCl 3 + 10 m LiCl electrolyte shows the best anti‐freezing property at −70°C with sufficient ionic conductivity of 1.42 mS cm −1 , and it further mitigates the In 3+ hydrolysis tendency and water‐related side reactions at elevated temperatures (+65°C). Consequently, in metal anode exhibits a highly reversible plating behavior with high Coulombic efficiencies of 99%–99.95% over a wide temperature range from −70 to +65°C. Rather than simply maximizing the electrolyte concentration, our work demonstrates that balancing hydrogen‐bond disruption and chloride‐rich ion coordination is the key to achieving wide‐temperature stability in aqueous trivalent electrolytes.