Current material design strategies on the copper chalcogenide cathodes for rechargeable magnesium batteries: a review

Rechargeable magnesium batteries (RMBs) are proposed to be conceivable rivals to replace lithium-ion batteries as next-generation energy storage devices. Nevertheless, the applications of RMBs are still hindered by the limited choice of high-performance cathode materials. Due to the impressively high theoretical capacity, copper chalcogenides have gained notable attention as a prospective electrode material. However, the implementation of copper chalcogenides with high energy density and rapid kinetics of Mg²⁺ insertion/extraction is in serious demand. In this review, the organized summary of all reaction mechanisms of copper chalcogenide cathodes for ion storage (intercalation, conversion and displacement type) is presented at first. Especially, five design and modification strategies for copper chalcogenide cathodes from macroscopic and microscopic aspects are highlighted, focusing on the size, morphology and structure, material composite, crystal structure and atomic substitution. This review ultimately offers practical recommendations and potential directions for the future development of copper chalcogenide cathodes for magnesium battery systems.