AUTHOR=Hao Ziyi , Jiang Weikang , Zhu Kaiyue 

TITLE=Carbon-encapsulated V2O3 nanorods for high-performance aqueous Zn-ion batteries

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.956610

DOI=10.3389/fchem.2022.956610

ISSN=2296-2646

ABSTRACT=<p>Searching for stable cathodes is of paramount importance to the commercial development of low-cost and safe aqueous Zn-ion batteries (AZIBs). V<sub>2</sub>O<sub>3</sub> is a good candidate for AZIB cathodes but has unsatisfied cycling stability. Herein, we solve the stability issue of a V<sub>2</sub>O<sub>3</sub> cathode by coating a robust carbon shell. Strong evidence was provided that V<sub>2</sub>O<sub>3</sub> was oxidized to favorable V<sub>2</sub>O<sub>5</sub>·nH<sub>2</sub>O during charging and the carbon shell could promote the oxidation of V<sub>2</sub>O<sub>3</sub> to V<sub>2</sub>O<sub>5</sub>·nH<sub>2</sub>O. The discharge capacity was increased from ∼45 mA h g<sup>−1</sup> to 336 mA h g<sup>−1</sup> after V<sub>2</sub>O<sub>3</sub> was oxidized to V<sub>2</sub>O<sub>5</sub>·nH<sub>2</sub>O, indicating a higher Zn<sup>2+</sup>-storage capability of V<sub>2</sub>O<sub>5</sub>·nH<sub>2</sub>O than V<sub>2</sub>O<sub>3</sub>. In addition, the rate-capability and long-term cycling performance are greatly enhanced after coating carbon shells on the surface of V<sub>2</sub>O<sub>3</sub> 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.</p>