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

The commercialization of the Zn-metal battery is hindered by dendrites and side reactions on the Zn anode. Here, the BaSO 4 coating is designed to address the problem of the Zn anode. The porous structure of the BaSO 4 coating improves the wettability to induce relatively uniform electrolyte flux and inhibits the two-dimensional diffusion of Zn 2+ , suppressing the growth of dendrites on the Zn anode. The BaSO 4 leads to a “space charge polarization” to promote the separation of positive and negative charge centers, the electrostatic effect promotes the transportation of Zn 2+ and reduces the occurrence of side reactions. Consequently, the BaSO 4 @Zn||BaSO 4 @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 K 2 V 6 O 16 ·1.5H 2 O (KVO) cathode. This work serves as a reference for solving problems and promoting the application of the Zn-metal battery.