LAUSR

Abstract Earth-abundant magnetite (Fe3O4) as cathode materials in aqueous zinc-ion batteries (ZIBs) is limited by its very low capacity and poor cycling. Here, a combined strategy based on carbon coating and electrolyte optimization is adopted to improve the performance of Fe3O4. The Zn-Fe3O4@C batteries display specific capacities of 93 mAh g−1 and 81% capacity retention after 200 cycles. Such performance is attributed to the enhanced electrical conductivity and structural stability of Fe3O4@C nanocomposites with suppressed iron dissolution. Experimental analysis reveals that the charge storage is contributed by diffusion-limited redox reactions and surface-controlled pseudocapacitance. A stretchable Zn-Fe3O4@C battery is further fabricated, showing stable performance when it is bent or stretched. Fe3O4 is a promising cathode material for cost-effective, safe, sustainable and wearable energy supplies.