Graphene-Coated Zn₃V₄(PO₄)₆/ZnMn₂(PO₄)₂ Heterostructured Cathode Materials for\nZinc-Ion Batteries

Abstract

Compared with commercial lithium-ion batteries (LIBs),\naqueous\nzinc-ion batteries (ZIBs) possess high safety, environmental friendliness,\nand abundant zinc resources, thus attracting the attention of researchers.\nThe exploration of high-capacity and high-stability cathode materials\nis one of the keys to realizing the practical application of ZIBs.\nHerein, we synthesize a graphene-coated Zn₃V₄(PO₄)₆/ZnMn₂(PO₄)₂ heterostructure cathode material (ZVP/ZMP@G). The coating\nof graphene is beneficial to improve the conductivity and cycle stability\nof the material. The rocking chair structure and reversible transformation\nof ZVP provide fast migration channels and huge storage space for\nZn²⁺. ZMP provides a certain capacity storage space and\npromotes the reversibility of the ZVP electrochemical conversion process.\nThanks to these advantages, the ZVP/ZMP@G||Zn full cell maintained\na capacity of 212.5 mAh g^–1 at a current density\nof 100 mA g^–1 after 100 cycles with 2 M ZnSO₄ + 0.1 M MnSO₄. It can cycle stably for 300 cycles\nat a current density of 500 mA g^–1 and exhibits\nexcellent rate performance. This strategy of constructing vanadium–manganese-based\nheterostructures can provide new ideas for the subsequent research\nof cathode materials and contribute to the development of ZIBs.