In situ electro-activation of commercial MnCO3 with porous structure obtained by acid etching for aqueous zinc ion batteries

Manganese-based materials are considered as the most promising cathodes in aqueous zinc ion battery due to their low cost, high energy density, and non-pollution. To obtain an excellent cathode with a potential for commercialization, it is very significant to convert commercial manganese-based materials to superior electrodes through a simple method. Herein, a simple acid etching is used to obtain commercial MnCO ₃ with porous structure. In situ electro-activation of commercial MnCO ₃ is performed, and the gradual transformation from inactive MnCO ₃ particles to active Mn ₂O ₃ and γ-MnO ₂ nanosheets is displayed by ex situ tests. The porous structure induced by acid etching is beneficial to the activated process and the pseudocapacitive storage. The enhanced capacitive process and charge transfer improve Mn dissolution during cyclic test. Meanwhile, ex situ analyses reveal the high reversibility of Zn ²⁺/H ⁺ storage. Significantly, the optimized electrode offers a high reversible capacity of 200 mA h g ⁻¹ at 0.05 A g ⁻¹ and a long cyclic life with 81/45 mA h g ⁻¹ at 0.5/2 A g ⁻¹ over 1200 cycles. This work proves the possibility of turning commercial material into outstanding electrode.