Facile Construction of Zn-Doped Mn3O4-MnO2 Vertical Nanosheets for Aqueous Zinc-Ion Battery Cathodes

Aqueous rechargeable batteries with good electrochemical performances have been considered as compelling alternatives in miniaturized energy storage units due to their small-size, better safety, greener manufacturing condition, and easy-to-recycle process. Herein, a binder-free manganese oxide (MnOx), comprising of MnO2 and Mn3O4 constructed by engineering it with zinc doping used as a cathode material for eco-friendly aqueous Zn ion battery is developed. A green and simple electrochemical deposition synthesis of Zn-doped Mn3O4-MnO2 nanocomposite with vertically-oriented 3D porous cereal-like nanosheet framework (ZnMM-NSs) is reproducibly performed directly onto the surface of AgCNT modified Ni foam in a mild aqueous ZnSO4+MnSO4 electrolyte. To the best of our knowledge, this is the first report on Zn doping in Mn3O4-MnO2 nanocomposite and the subsequent device assembly for aqueous zinc-ion batteries. Zinc doping induced electrical/ionic conductivity enhancement, along with more active sites provided by 3D porous cereal-like nanostructures and multiple Mn valences, this ZnMM-NSs cell can deliver a high capacity, good rate performance, and satisfying cycling stability. Also, the Zn-doped manganese oxides are obtained by a green method, which can reduce the entire cost, the usage of toxic solvents, the consumption of energy, and the disposable by-product, paving the way for developing cost-effective, easy-to-recycle, and environmentally friendly next-generation energy storage systems.

Automated summary

A binder-free manganese oxide material was developed as a cathode material for aqueous zinc-ion batteries. This material exhibits good electrochemical performances, high capacity, good rate performance, and cycling stability. Additionally, the green synthesis of this material reduces costs, minimizes the use of toxic solvents, saves energy, and enables easy recycling.