Exploring anodes for calcium-ion batteries

Calcium ion batteries have been increasingly explored as an alternative energy storage system as industry begins to manoeuvre towards an age of ‘Beyond lithium-ion’ research and development. However, using calcium metal as the battery's anode presents a multitude of issues, including the inability to strip ions off the metal, and the creation of an inactive passivation layer. Most research conducted around calcium ion batteries focuses on the electrolytic and cathodic study, whereas little focuses on the anode, due in part to the complexity and difficulty in resolving its challenges. Herein, this review will address the issues calcium has, including its lack of reversibility and solid electrolyte interface formation, as well as explore the alternative anode materials that have been utilised, noting their viability and future prospects.