Calcium metal batteries move closer to commercialisation

Calcium metal batteries could provide an alternative to lithium-ion batteries (LIBs) as calcium is abundant, inexpensive and has higher energy density potential than LIBs. The element’s properties are also thought to help accelerate ion transport and diffusion in electrolytes and cathode materials, giving it an advantage over other LIB alternatives including magnesium and zinc.

Despite these advantages, calcium metal batteries face several challenges that must be overcome before they reach commercial viability. The lack of an efficient electrolyte and the absence of cathode materials with sufficient Ca²⁺ storage capabilities have proved to be the main obstacles.

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In 2021, some members of the current research group provided a solution when they developed a new fluorine-free calcium electrolyte based on a hydrogen (monocarborane) cluster. The electrolyte is said to have demonstrated markedly improved electrochemical performances such as high conductivity and high electrochemical stabilities.

"For our current research, we tested the long-term operation of a Ca metal battery with a copper sulphide (CuS) nanoparticle/carbon composite cathode and a hydride-based electrolyte," said Kazuaki Kisu, assistant professor at Tohoku University's Institute for Materials Research (IMR).