Advanced lithium storage properties and first-principles investigation of Zn3V3O8/VO2@NG heterostructure

In this paper, a new composites material Zn 3 V 3 O 8 /VO 2 @Nitrogen graphene (ZnVO/VO 2 @NG) was synthesized, and its structural features and electrochemical properties were systematically characterized. The electrochemical analysis reveals that the electrode exhibits fast electron/lithium ion transport kinetics, and its pseudocapacitive behavior storage characteristics can achieve ultra-fast dynamic response. The ZnVO/VO 2 @NG electrode maintains a high reversible specific capacity of 995 mAh g -1 after 700 cycles at 1 A g -1 , and an impressive rate capability of 540 mAh -1 at 5 A g -1 . In addition, first-principles calculation reveals that ZnVO/VO 2 @NG exhibits zero-bandgap metallic properties with excellent electrical conductivity. Meanwhile, differential charge density and adsorption energy calculations further demonstrates that Li-ions at the interface of ZnVO and NG have a charge transfer as high as 1.71 eV, and a corresponding adsorption energy of -5.46 eV, which suggests the existence of strong lithium interactions at this interface. These findings provide an important theoretical basis for a deeper understanding of the lithium ion storage properties at the heterogeneous interface.