Carbon-encapsulated V2O3 nanorods for high-performance aqueous Zn-ion batteries
Ziyi Hao, Weikang Jiang, Kaiyue Zhu
Abstract
Searching for stable cathodes is of paramount importance to the commercial development of low-cost and safe aqueous Zn-ion batteries (AZIBs). V 2 O 3 is a good candidate for AZIB cathodes but has unsatisfied cycling stability. Herein, we solve the stability issue of a V 2 O 3 cathode by coating a robust carbon shell. Strong evidence was provided that V 2 O 3 was oxidized to favorable V 2 O 5 ·nH 2 O during charging and the carbon shell could promote the oxidation of V 2 O 3 to V 2 O 5 ·nH 2 O. The discharge capacity was increased from ∼45 mA h g −1 to 336 mA h g −1 after V 2 O 3 was oxidized to V 2 O 5 ·nH 2 O, indicating a higher Zn 2+ -storage capability of V 2 O 5 ·nH 2 O than V 2 O 3 . In addition, the rate-capability and long-term cycling performance are greatly enhanced after coating carbon shells on the surface of V 2 O 3 nanorods. Therefore, the presented strategy of introducing carbon shells and fundamental insights into the favorable role of carbon shells in this study contribute to the advancement of highly stable AZIBs.