Efficient CuO coating on assembled Cu ₂ V ₂ O ₇ nanoflakes for better lithium storage performance

Abstract The high theoretical capacity of metal vanadates is often negated by rapid capacity decay and inferior electrochemical response due to their structural reconstruction during lithiation. Herein, a Cu ₂ V ₂ O ₇ nanoflake 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 is systematically investigated. Such synthesis spontaneously generates a multifunctional secondary CuO phase, which serves multiple purposes. It retards the single-step amorphization of Cu ₂ V ₂ O ₇ during initial discharge and establishes a heterophase interface with Cu ₂ V ₂ O ₇ to accelerate the Li-storage kinetics while contributing additional redox-active sites for extra capacity. Consequently, the C@Cu ₂ V ₂ O ₇ hybrid anode delivers a reversible capacity of 997.4 mAh g ⁻¹ after 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 ⁻¹ over 2000 cycles with a capacity retention of 56.36% after 8000 cycles. These findings collectively endorse the in situ growth of a protective oxide layer as a potent design principle for high-performance metal vanadate-based anodes.