Figure 1 (IMAGE) Tohoku University Caption Schematic of a prototype Ca metal battery. The battery comprises a Ca2+ storing positive electrode containing the CuS cathode and Ca metal anode with a hydrogen cluster electrolyte. Cycling performance of the Ca-CuS battery. Credit Kazuaki Kisu Usage Restrictions Reporters may use freely these materials in news coverage with appropriate credit information. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.