Dual-cation preintercalated and amorphous carbon confined vanadium oxides as a superior cathode for aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (AZIBs) that directly use metallic zinc as anode and mildly acidic Zn2+-containing aqueous solutions as electrolytes have exhibited promising complementarity for well established lithium-ion batteries. The fabrication of high-voltage, high-capacity, and durable cathode and stable anode are the burning issues of fabricating high-performance AZIBs. Herein, the small amount of dual-cation preintercalated and amorphous carbon confined vanadium dioxide (Ni0.006Ca0.0045VO2@C) was prepared for high-performance Zn2+-storage materials, and subsequent in situ electrochemical anodic oxidation strategy was used to convert Ni0.006Ca0.0045VO2@C to delta-(Ni,Ca)V2O5@C as high-capacity AZIB cathode. The elaborate architecture not only showed a high specific capacity of 433.8 mAh g(-1) at 0.1 A g(-1) but also retained a reversible capacity of 74 mAh g(-1) after 4000 cycles at 5 A g(-1). In addition, the Zn2+/H+ co-intercalation mechanism was also verified by employing ex situ XRD and ex situ XPS. Finally, the flexible quasi-solid-state ZIBs were also assembled with the Ni0.006Ca0.0045VO2@C as cathode and polyvinyl alcohol hydrogel as electrolyte, suggesting its promising application for the superior Zn2+- storage performance. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study prepared new materials for high-performance Zn2+ storage and converted them into high-capacity AZIB cathodes using an in situ electrochemical oxidation strategy, achieving high specific capacity and stable cycling performance. Additionally, the Zn2+/H+ co-intercalation mechanism was verified, providing new insights for the design of future aqueous zinc-ion batteries.