MIL‐47(V) Derived V<sub>2</sub>O<sub>5</sub>@Carbon Core‐Shell Microcuboids with Oxygen Vacancies as Advanced Conversion Cathodes for High‐Performance Zinc‐Ion Batteries
Tianqi He, Jinhang Li, Zhengzhi Luo, Yuqiang Zhang, Yingying Zhao, Xitian Zhang, Yujin Chen
Abstract
Abstract Vanadium pentoxide (V 2 O 5 ) has been considered one of the most promising cathodes for zinc‐ion batteries (ZIBs) due to its outstanding theoretical capacity (589 mAh g −1 ). However, it remains great challenge to achieve the high capacity, limited to the poor electronic conductivity and sluggish ionic diffusion kinetics of V 2 O 5 . Herein, a controllable strategy is proposed to synthesize V 2 O 5 @carbon core‐shell microcuboids with oxygen vacancies (V 2 O 5‐ x @CCSMs) derived from MIL‐47(V) used for cathodes of ZIBs. The obtained V 2 O 5‐ x @CCSMs cathode delivers high capacities of 485.4 and 392.1 mAh g −1 at 0.1 and 2.0 A g −1 , respectively. The superior electrochemical performances originate from the nano‐sized particles of V 2 O 5 , oxygen vacancies and carbon shell. Further, ex‐situ XRD indicates V 2 O 5 undergoes a shrinking core model conversion reaction at initial cycling to a new phase of Zn 3 V 2 O 7 (OH) 2 ⋅ 2H 2 O, which is an ideal host for Zn 2+ . Our work offers an innovative strategy to develop high‐capacity cathode in ZIBs.