Although rechargeable batteries that use light electropositive metal anodes are attractive, electrodeposition of calcium has proved difficult. Calcium plating at moderate temperatures using conventional organic electrolytes has now been demonstrated. The development of a rechargeable battery technology using light electropositive metal anodes would result in a breakthrough in energy density1. For multivalent charge carriers (Mn+), the number of ions that must react to achieve a certain electrochemical capacity is diminished by two (n = 2) or three (n = 3) when compared with Li+ (ref. 2). Whereas proof of concept has been achieved for magnesium3,4,5, the electrodeposition of calcium has so far been thought to be impossible6 and research has been restricted to non-rechargeable systems7,8,9,10. Here we demonstrate the feasibility of calcium plating at moderate temperatures using conventional organic electrolytes, such as those used for the Li-ion technology. The reversibility of the process on cycling has been ascertained and thus the results presented here constitute the first step towards the development of a new rechargeable battery technology using calcium anodes.

Towards a calcium-based rechargeable battery