Green-low-cost rechargeable aqueous zinc-ion batteries using hollow porous spinel ZnMn2O4 as the cathode material

Abstract

Rechargeable aqueous zinc-ion batteries (ZIBs) have been receiving much attention recently due to their potential large-scale applications for energy storage, although only a few cathode materials have been reported as the intercalation hosts for divalent Zn²⁺ ions. Here, we report competitive ZIBs based on hollow porous ZnMn₂O₄ as the cathode and zinc as the anode. ZnMn₂O₄ is firstly prepared through a solvothermal carbon template dispersed by polyvinyl pyrrolidone, followed by an annealing process. The galvanostatic charge–discharge measurement demonstrates that a reversible discharge capacity of 106.5 mA h g⁻¹ at 100 mA g⁻¹ after 300 cycles can be achieved with no capacity decay after the addition of 0.05 mol L⁻¹ of MnSO₄ into the electrolyte. Meanwhile, it exhibits a high capacity of 70.2 mA h g⁻¹ at a large current density of 3200 mA g⁻¹. The excellent cycle and rate performances are attributed to the synergistic effect of the deficient spinel structure of hollow porous ZnMn₂O₄ with residual carbon distribution and the inhibition of Mn dissolution during the charge/discharge process.