High-Performance Aqueous Zinc-Manganese Battery with Reversible Mn 2+ /Mn 4+ Double Redox Achieved by Carbon Coated MnO x Nanoparticles

摘要

There is an urgent need for low-cost, high-energy-density, environmentally friendly energy storage devices to fulfill the rapidly increasing need for electrical energy storage. Multi-electron redox is considerably crucial for the development of high-energy-density cathodes. Here we present high-performance aqueous zinc–manganese batteries with reversible Mn~(2+)/Mn~(4+) double redox. The active Mn~(4+) is generated in situ from the Mn~(2+)-containing MnO_(x ) nanoparticles and electrolyte. Benefitting from the low crystallinity of the birnessite-type MnO_(2) as well as the electrolyte with Mn~(2+) additive, the MnO_(x ) cathode achieves an ultrahigh energy density with a peak of 845.1?Wh?kg~(?1) and an ultralong lifespan of 1500 cycles. The combination of electrochemical measurements and material characterization reveals the reversible Mn~(2+)/Mn~(4+) double redox (birnessite-type MnO_(2?)??monoclinic MnOOH and spinel ZnMn_(2)O_(4)???Mn~(2+) ions). The reversible Mn~(2+)/Mn~(4+) double redox electrode reaction mechanism offers new opportunities for the design of low-cost, high-energy-density cathodes for advanced rechargeable aqueous batteries.