Zn-doped manganese tetroxide/graphene oxide cathode materials for high-performance aqueous zinc-ion battery

Due to its abundant zinc resources, high safety and low cost, aqueous zinc-ion batteries (AZIBs) are considered one of the most interesting lithium-ion battery replacement technologies. Herein, a novel Zn-doped cathode material is achieved via pre-intercalation of Zn²⁺ into the prepared manganese tetroxide (Mn₃O₄)/graphene oxide (GO). The pre-intercalation of Zn²⁺ effectively increases the lattice spacing of Mn₃O₄ and reduces the barrier of insertion/extraction of Zn²⁺, thus improving the kinetic properties of the material. Meanwhile, the conductive carbon skeleton GO successfully combines with polyethyleneimine and Mn₃O₄, which can expand electron and ion conductivity and avoid chemical bulk change. This unique structure enables the Zn-doped cathode a reversible specific capacity with excellent performance (170 mAh g⁻¹ at 200 mA g⁻¹). Furthermore, the diffusion coefficient of the Zn-doped cathode is 10⁻⁹–10⁻¹⁰cm⁻² s⁻¹. Therefore, this study introduces a viable approach for the practical implementation of advanced electrode materials in AZIBs applications.