Zn-doped MnCO3 as cathode material for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs), known for their high discharge capacity, low cost, and relatively low environmental impact, are a promising alternative for advanced energy storage. The exploration of novel electrode materials and the reaction mechanisms in AZIBs have garnered considerable attention. MnCO3, as an electrode material, is known for its safety, nontoxic nature, and widespread availability as a raw material. Nevertheless several constraints limit the use of MnCO3 cathodes, including short lifespan and reduced electrical conductivity. To resolve these shortcomings, compounds containing Zn, Co and Ni elements were added to improve the properties of the MnCO3 material. The Zn doped MnCO3 (MnCO3-Zn-0.0015M) was successful synthesized by solvothermal, which presents a special microstructure of spherical shell. Not only does the spherical microstructure of the shell enhance the packing density, but the pore configuration within the shell layer also facilitates the insertion and extraction of Zn2+. The MnCO3-Zn-0.0015M material, operating at a current density of 0.1 A∙g-1, exhibited an impressive discharge capacity of 120.4 mAh∙g-1 along with remarkable rate performance. The cathode sustained 75.29% of its capacity following 1000th cycles at current density of 1.0 A∙g-1. Considering these results, the MnCO3-Zn-0.0015M material developed in this study opens a novel avenue for optimizing the use of manganese compounds in aqueous zinc-ion batteries.