Calcium Molybdenum Bronze as a Stable High-Capacity Cathode Material for Calcium-Ion Batteries

Calcium-ion batteries (CIBs) are gaining increasing attention due to their theoretically high capacity, owing to the divalency of calcium, and low cost. However, only a few calcium insertion electrode materials are reported, and most of them exhibit low capacity or poor cyclability in nonaqueous electrolytes. Herein, we demonstrated high-performance calcium molybdenum bronze Ca_0.13MoO₃·(H₂O)_0.41 as a potential CIB cathode material at room temperature, with a reversible discharge capacity of 192 mAh g^–1 at 86 mA g^–1, an average voltage of 2.4 V (vs Ca/Ca²⁺), and excellent cyclability. This work provides the feasibility of developing high-capacity CIB cathode materials.