Highly reversible Zn anode enabled by porous BaSO4 coating with wide band gap and high dielectric constant

Abstract

The commercialization of the Zn-metal battery is hindered by dendrites and side reactions on the Zn anode. Here, the BaSO4 coating is designed to address the problem of the Zn anode. The porous structure of the BaSO4 coating improves the wettability to induce relatively uniform electrolyte flux and inhibits the two-dimensional diffusion of Zn2+, suppressing the growth of dendrites on the Zn anode. The BaSO4 leads to a “space charge polarization” to promote the separation of positive and negative charge centers, the electrostatic effect promotes the transportation of Zn2+ and reduces the occurrence of side reactions. Consequently, the BaSO4@Zn||BaSO4@Zn battery displays a longer lifespan (122 h–1200 h) and a lower polarization (74.0 mV–47.2 mV) at 2 mA cm−2. The full battery exhibits an extended lifespan (3000 cycles) and a stable coulombic efficiency at 5 A g−1 when coupled with the K2V6O16·1.5H2O (KVO) cathode. This work serves as a reference for solving problems and promoting the application of the Zn-metal battery.