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

Compared with commercial lithium-ion batteries (LIBs), aqueous zinc-ion batteries (ZIBs) possess high safety, environmental friendliness, and abundant zinc resources, thus attracting the attention of researchers. The exploration of high-capacity and high-stability cathode materials is one of the keys to realizing the practical application of ZIBs. Herein, we synthesize a graphene-coated Zn 3 V 4 (PO 4 ) 6 /ZnMn 2 (PO 4 ) 2 heterostructure cathode material (ZVP/ZMP@G). The coating of graphene is beneficial to improve the conductivity and cycle stability of the material. The rocking chair structure and reversible transformation of ZVP provide fast migration channels and huge storage space for Zn 2+ . ZMP provides a certain capacity storage space and promotes the reversibility of the ZVP electrochemical conversion process. Thanks to these advantages, the ZVP/ZMP@G||Zn full cell maintained a capacity of 212.5 mAh g –1 at a current density of 100 mA g –1 after 100 cycles with 2 M ZnSO 4 + 0.1 M MnSO 4 . It can cycle stably for 300 cycles at a current density of 500 mA g –1 and exhibits excellent rate performance. This strategy of constructing vanadium–manganese-based heterostructures can provide new ideas for the subsequent research of cathode materials and contribute to the development of ZIBs.