Introduction of oxygen vacancies and amorphous layers into copper vanadium oxide for better lithium ion battery performance

The introduction of protective layers and defects in electrodes is an effective strategy to improve the reversible capacity and cyclic stability of batteries. In the present work, using a cuprous oxide template, copper vanadate oxide with a diverse morphology is synthesized by an in-situ etching process followed by calcination. Moreover, oxygen vacancies and an amorphous copper vanadium oxide shell are successfully introduced into moniliform Cu3V2O8 (denote as m-Cu3V2O8@aCVO) by changing the template morphology from Cu2O polyhedrons to polypyrrole-coated Cu2O nanowires. The electrochemical performances of the samples are evaluated using a lithium half-cell as the anode. The m-Cu3V2O8@aCVO manifests superior rate performance (428 mAh g−1 at 5 A g−1) and cyclic stability (938 mAh g−1 is obtained after 200 cycles), the microstructure is well-maintained after cycles. The Li-storage mechanism of the electrode changed from diffusion-controlled to pseudo-capacitance-controlled due to the introduction of oxygen vacancies. The excellent electrochemical performance could be attributed to the introduction of oxygen vacancies and the protective layer, which improves the pseudo-capacitance and structural durability of the electrode during the cyclic process. This work provides new insight into the design of high-performance anodes for energy storage applications.