Earth-abundant magnetite with carbon coatings as reversible cathodes for stretchable zinc-ion batteries

Earth-abundant magnetite(Fe_(3)O_(4))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 Fe_(3)O_(4).The Zn-Fe_(3)O_(4)@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 Fe_(3)O_(4)@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-Fe_(3)O_(4)@C battery is further fabricated,showing stable performance when it is bent or stretched.Fe_(3)O_(4) is a promising cathode material for cost-effective,safe,sustainable and wearable energy supplies.