Calcium metal battery capable of more than 500 cycles

Rechargeable calcium metal batteries are emerging as a promising option in the quest for next-generation energy storage devices, which are expected to have higher energy densities and lower costs than existing lithium-ion batteries. However, challenges, such as calcium metal passivation by electrolytes and a lack of cathode materials with efficient calcium ions storage capabilities, impede the technology’s practical development.

To overcome these limitations, researchers at Tohoku University in Japan recently developed a prototype calcium metal rechargeable battery capable of more than 500 cycles of repeated charging and discharging. The battery was developed with a hydride-based electrolyte and copper sulfide (CuS) nanoparticle/carbon composite cathode. It demonstrated better performance than state-of-the-art calcium metal batteries in terms of both the rate capability and cycle life.

The combination of a CuS/C nanocomposite and a tailored monocarborane electrolyte solution of Ca(CB₁₁H₁₂)₂ in dimethoxyethane/tetrahydrofuran (DME/THF) enabled a calcium metal battery with capacity retention of 92% based on the capacity of the 10th cycle.

“This study confirms the feasibility of the long-term operation of Ca metal anodes and can expedite the development of Ca metal batteries,” the researchers wrote in “Calcium Metal Batteries with Long Life Using a Hydride-Based Electrolyte and Copper Sulfide Electrode,” which was recently published in Advanced Science.