Gradient Graphdiyne Induced Copper and Oxygen Vacancies in Cu0.95 V2 O5 Anodes for Fast-Charging Lithium-Ion Batteries

Abstract

Vacancies can significantly affect the performance of metal oxide materials. Here, a gradient graphdiyne (GDY) induced Cu/O-dual-vacancies abundant Cu_0.95 V₂ O₅ @GDY heterostructure material has been prepared as a competitive fast-charging anode material. Cu_0.95 V₂ O₅ self-catalyzes the growth of gradient GDY with rich alkyne-alkene complex in the inner layer and rich alkyne bonds in the outer layer, leading to the formation of Cu and O vacancies in Cu_0.95 V₂ O₅ . The synergistic effect of vacancies and gradient GDY results in the electron redistribution at the hetero-interface to drive the generation of a built-in electric field. Thus, the Li-ion transport kinetics, electrochemical reaction reversibility and Li storage sites of Cu_0.95 V₂ O₅ are greatly enhanced. The Cu_0.95 V₂ O₅ @GDY anodes show excellent fast-charging performance with high capacities and negligible capacity decay for 10 000 cycles and 20 000 cycles at extremely high current densities of 5 A g^-1 and 10 A g^-1 , respectively. Over 30 % of capacity can be delivered in 35 seconds.

Keywords: Cu0.95V2O5; Fast Charging; Gradient Graphdiyne; Lithium-Ion Batteries; Self-Catalysis; Vacancy.