Conductive coating, cation-intercalation, and oxygen vacancies co-modified vanadium oxides as high-rate and stable cathodes for aqueous zinc-ion batteries

Layered vanadium oxides are promising cathode materials for zinc-ion batteries (ZIBs) owing to their high capacity, but the sluggish electron/ion migration kinetics and structural collapse/dissolution severely limit their Zn2+-storage performance. Herein, poly(3,4-ethylenedioxythiophene) coated and Mn2+-intercalated vanadium oxides with rich oxygen vacancies (MnVOH@PEDOT) are prepared as the cathodes for ZIBs. The PEDOT coating, synergistic with oxygen vacancies, tailors the electron conductivity, and the Mn2+-intercalation enlarges the interlayer spacing for rapid Zn2+-ions diffusion. In addition, the pre-intercalated Mn2+-ions act as pillars to stabilize the structure, and the PEDOT coating prevents the direct contact of vanadium oxides with electrolyte to inhibit its dissolution during cycling. Thus, the MnVOH@PEDOT cathode exhibits superior discharge capacity, favorable rate capability (336.0 mAh g(-1) at 8 A g(-1)), and satisfying cyclic durability (84.8% capacity retention over 2000 cycles). This work offers a facile and synergistic design strategy for achieving favorable cathodes for ZIBs.

Automated summary

Layered vanadium oxides coated with poly(3,4-ethylenedioxythiophene) and Mn2+-intercalated with rich oxygen vacancies are prepared as cathodes for zinc-ion batteries. The PEDOT coating improves electron conductivity, while Mn2+ intercalation increases interlayer spacing for rapid Zn2+ ion diffusion. The pre-intercalated Mn2+ ions act as pillars to stabilize the structure, and the PEDOT coating prevents direct contact of vanadium oxides with electrolyte, inhibiting dissolution during cycling. The MnVOH@PEDOT cathode exhibits superior discharge capacity, favorable rate capability, and satisfying cyclic durability.