Cu-MOF-derived and porous Cu0.26V2O5@C composite cathode for aqueous zinc-ion batteries

Abstract

One fundamental issue for developing high-performance Zn-ion batteries (ZIBs) is the exploration of stable and efficient cathode materials that can reversibly intercalate zinc ions at a high capacity and potential. Layered vanadium oxides have been regarded as a suitable candidate for this purpose due to their high zinc-ion storage capacity. However, the sluggish kinetics of zinc-ion intercalation/deintercalation and the poor conductivity of vanadium oxides are still the bottle bottlenecks that impede the further enhancement of their performance for ZIBs. Addressing this issue, we herein demonstrate a direct impregnation and conversion strategy to prepare a Cu-doped V2O5 and hierarchical porous carbon (Cu0.26V2O5@C) composite as the cathode for ZIBs. In this protocol, the Cu doping can promote the zinc-ion migration by broadening and stabilizing the layered structure of V2O5, the hierarchical porosity can enlarge the contact between the active material and the electrolyte to achieve efficient infiltration of the electrolyte into the material, while the carbon host can improve the electronic conductivity. The combination of these merits thus delivers a high specific capacity (328.8 mAh g−1 at 0.2 A g−1), high rate performance (163.8 mAh g−1 at 2 A g−1), and excellent long-term cyclic stability with 93.5% capacity retention after 500 cycles.