Solid-Phase Synthesis of ZnO@Bi2O3 Core–Shell Composites for Long-Life NiZn Batteries

Abstract

In this work, core-shell ZnO@Bi2O3 composites are fabricated by a solid-phase method. SEM, TEM, and element mapping images confirm the uniform distribution of Bi2O3 film over the surface of ZnO particles. The formation mechanism is proposed. In addition, the electrochemical performance of core–shell ZnO@Bi2O3 composites is measured with the help of CV and EIS, and the optimal reaction parameters are obtained. Furthermore, the optimized ZnO@Bi2O3 with 3 wt % Bi2O3 as anode materials is used for the NiZn battery, which has delivered a high energy density of 177.23 W h kg–1 and outstanding cycle stability up to 3400 cycles. The Bi2O3 layer suppresses hydrogen evolution and effectively mitigates the migration of Zn(OH)42–, dendrite formation, and passivation of zinc anode due to substance effect and as ion sieve. We propose that this is a facile and easy synthetic method that can be scaled and may provide guidance for the synthesis of other core–shell structures.