A vacancy-enriched amorphous molybdenum oxide electrodeposited on CuxO for enhanced aqueous energy storage

Introducing disorder into crystalline hierarchical nanostructure along with defect engineering can be utilized to systematically modulate the electronic structure of copper-based materials to enhance electrochemical performance. Herein, a Cu x O/MoO y (x:1–2, y:2–3) self-supporting electrode on 3D copper foam is prepared by simple electrodeposition method, in which the crystallized Cu x O is coated by an ultra-thin amorphous MoO y layer. It is shown that the strong binding between the active material and substrate further enhances the structural stability. The synergistic interaction among multi-components, coupled with oxygen vacancies, greatly optimizes the electronic structure of the material, then improves its conductivity, further accelerates electron transfer kinetics. Therefore, Cu x O/MoO y with high areal mass loading exhibits a specific areal capacity of 12.89 mA h·cm −2 at 20 mA cm −2 , even maintained 92 % capacity retention at 100 mA cm −2 . The conducted hybrid capacitor exhibited the maximum energy density of 0.9 mWh·cm −2 at the power density of 7.5 mW cm −2 , demonstrating great potential in practical application.