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

Abstract

In this work, core-shell ZnO@Bi 2 O 3 composites are fabricated by a solid-phase method. SEM, TEM, and element mapping images confirm the uniform distribution of Bi 2 O 3 film over the surface of ZnO particles. The formation mechanism is proposed. In addition, the electrochemical performance of core− shell ZnO@Bi 2 O 3 composites is measured with the help of CV and EIS, and the optimal reaction parameters are obtained. Furthermore, the optimized ZnO@Bi 2 O 3 with 3 wt % Bi 2 O 3 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 Bi 2 O 3 layer suppresses hydrogen evolution and effectively mitigates the migration of Zn(OH) 4 2− , 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.