Nitrogen-doped carbon/V2O3 nanorod composites as cathode material for high-performance aqueous Zn-ion battery

At present, the main challenge facing the aqueous zinc ion batteries (ZIBs) system is to find a kind of cathode material with high stability and large capacity. In this study, the precursor of metal-organic framework (MOF) was synthesized by hydrothermal method. Then, the carbon composite vanadyl oxide (N/C@V2O3) was synthesized by vacuum heat treatment and used as cathode material for ZIBs. The electrode material underwent an in situ phase change process during the first charge, where the corundum structure of N/C@V2O3 was oxidized and transformed into layered basic zinc vanadate (N/C@Zn2(OH)3(VO3)). The layered structure helps to achieve fast and stable storage and transport of zinc ions. Resulting in stable electrochemical performance, high specific capacity up to 285 mAh g−1 (1 A g−1), and ultra-long cycle stability (capacity retention of 98% at 10 A g−1 after 4500 cycles). In situ phase transition takes place inside the battery, which is a simple method to improve the theoretical capacity limit of materials, and has positive significance for realizing large magnification and long cycle ZIBs cathode materials.