High-capacity cathode for aqueous zinc-ion battery based on MnOx-modified bismuth vanadate

Abstract

Aqueous Zn-ion batteries (AZIBs) are a perspective energy storage technical due to their excellent safety levels while maintaining cost-effectiveness, and large theoretical specific capacity. However, the capability mismatch between cathode and anode brings the low specific capacity and unsatisfactory cycle life, which blocks the large-scale application of AZIBs for renewable energy sources and the smart grid industry. Herein, we constructed a decahedral BiVO4/MnOx nanosheets cathode to boost the charge/discharge performance of AZIB by a directional drive strategy. Due to the MnOx nanosheets selectivity growth on {110} facet of decahedral BiVO4 and the laminar structure of the BiVO4/MnOx composite, the channels of electron transfer are established between BiVO4 and MnOx nanosheets, which restrain the instability of manganese oxides and accelerate the insertion/extraction of Zn2+, and further enhance the specific capacity and cycle life of AZIB. The BiVO4/MnOx cathode shows a high specific capacity of 567.5 mAh g−1 and the assembled AZIB exhibits an outstanding energy density of 365.5 Wh kg−1, superior rate performance, stable long cycle life, and superior long-cycle capability (6600 cycles at 3 A g−1). The above findings provide a new way for high capacity and high life cathode materials of AZIBs.