Zinc ion stabilized MnO2 nanospheres for high capacity and long lifespan aqueous zinc-ion batteries

Rechargeable zinc-ion batteries based on Zn/MnO2 in neutral aqueous electrolytes are promising for grid-scale energy storage applications owing to their favorable merits of high safety, low cost and environmental benignity. However, MnO2 cathodes are subjected to the challenging issues of poor cyclability and low rate capability. Herein, we report a facile chemical method for the preparation of mesoporous MnO2 flower-like nanospheres with the layered framework stabilized by hydrated Zn2+ pillars. The MnO2 cathode could deliver a reversible specific capacity of 358 mA h g(-1) at 0.3 A g(-1) after 100 cycles, a high rate capacity of 124 mA h g(-1) at 3.0 A g(-1), and excellent operating stability over 2000 cycles. Structural and morphological investigations demonstrate an energy storage mechanism of co-insertion/extraction of H+ and Zn2+ accompanied by deposition/dissolution of zinc sulfate hydroxide hydrate flakes on the electrode surface. The superior electrochemical performance makes the zinc ion stabilized MnO2 promising for high capacity and long lifespan zinc-ion batteries.