Architecting a 3D continuous C/CuVO₃@Cu composite anode for lithium-ion storage

Vanadium (V)-based oxides with a high theoretical capacity are an alternative anode for lithium-ion (Li⁺) batteries, but they are still limited by the poor conductivity, large volume change and low active material mass loading. Herein, a three-dimensional (3D) continuous C/CuVO₃@Cu composite anode with high copper (II) metavanadate (IV) (CuVO₃) mass loading is synthesized by the combination of high-energy ball milling, non-solvent-induced phase separation and heat treatment. The copper (Cu) framework can enhance electron/ion conductivity in coordination with amorphous carbon (C). Furthermore, the macropore channels in the copper framework can provide buffer space for the volume expansion of active material copper (II) metavanadate (IV) during lithiation/delithiation. As a result, this 3D continuous C/CuVO₃@Cu composite anode achieves a high copper (II) metavanadate (IV) mass loading of about 3.8 mg/cm², delivering a reversible capacity of 479 mAh/g at 100 mA/g after 120 cycles. More importantly, a long life span is achieved with a reversible capacity of 268 mAh/g even after 1700 cycles at a high current density of 1000 mA/g, demonstrating excellent cycle performance. This work provides a way to develop 3D continuous composite material anodes with extraordinary electrochemistry performance for next-generation energy-storage devices.