Self-catalytic CuFeS2 cathodes for magnesium batteries

Conversion-type cathode materials are promising candidates for achieving high capacities in rechargeable magnesium batteries (RMBs) via multi-electron redox reactions. Nevertheless, their practical performance is often limited by the intrinsic energy barriers of the conversion reactions, leading to low reversible capacity and poor cycling stability. Herein, a self-catalytic CuFeS 2 electrode architecture is designed to enhance the electrochemical performance of RMBs. During the initial discharge, metallic Cu nanocatalysts are generated in-situ from CuFeS 2 , preceding the subsequent metal sulfide conversion process ( e.g. FeS derived from CuFeS 2 ). Moreover, these catalytically active Cu sites form atomic-scale interfaces with the FeS phase, effectively lowering the Fe−S bond dissociation energy barrier. Benefiting from this catalytic effect, the optimized CuFeS 2 cathode delivers remarkable reversible capacities of 293 mAh g −1  at 0.05 A g −1 and 135 mAh g −1 remained at 2 A g −1 . Moreover, a high capacity of 110 mAh g −1 is maintained after 700 cycles. This work establishes an effective design paradigm for developing high-capacity, durable conversion-type cathodes for advanced magnesium battery systems.