Efficient CuO coating on assembled Cu₂V₂O₇nanoflakes for better lithium storage performance

The high theoretical capacity of metal vanadates are often negated by rapid capacity decay and inferior electrochemical response due to their structural reconstruction during lithiation. Herein, a Cu₂V₂O₇nanoflake architecture assembled on a conductive, doped graphitic carbon scaffold is synthesized via a coupled hydrothermal-annealing process, and the influence of varied thermal treatments on its morphology and lithium storage behavior are systematically investigated. Such synthesis spontaneously generates a multifunctional secondary CuO phase, which serves a multiple purpose. It retards the single-step amorphization of Cu₂V₂O₇during initial discharge, and establishes a hetero-phase interface with Cu₂V₂O₇to accelerate the Li-storage kinetics while contributes additional redox-active sites for extra capacity. Consequently, the C@Cu₂V₂O₇hybrid anode deliver a reversible capacity of 997.4 mAh g^-1after 150 cycles at 0.1 A g^-1, and remarkably, even under a high current density of 2 A g^-1, it sustains a capacity of 366.07 mAh g^-1over 2000 cycles with a capacity retention of 56.36% after 8000 cycles. These findings collectively endorse the in situ growth of protective oxide layer as a potent design principle for high-performance metal vanadates-based anodes.