Plating and Stripping Calcium at Room Temperature in an Ionic-Liquid Electrolyte

Calcium batteries are an emerging, next generation energy storage technology undergoing intense research toward viable operation. A key aspect in their development is plating and stripping of a calcium metal anode in suitable electrolytes. Herein, we report that calcium can be plated and stripped at room temperature in an ionic-liquid-based electrolyte. Thick continuous deposits (∼20 μm) of crystalline calcium are plated and stripped over 10 cycles to areal capacities of 2.2 mAh cm–2 at a current density of 0.56 mA/cm2. This work presents ionic liquids as viable electrolytes for calcium anodes to enable redox activity for calcium batteries.