Building block effect induces horizontally oriented bottom Zn(002) deposition for a highly stable zinc anode

Abstract

The practical application of zinc anodes for rechargeable aqueous zinc-ion batteries is hindered to uncontrollable dendritic zinc deposition and side reactions. And the deposition of zinc is like building blocks layer by layer, typically considered as nucleation, growth and evolution driven by electric field. Yet the important role of the bottommost deposits is generally ignored. Here, we developed a highly self-adaptable polydimethylsiloxane (PDMS)/montmorillonite (MMT) film to regulate the process of zinc deposition sustainably. In the nucleation and growth stages of zinc, the two-step regulation of the building block effect benefits from the adsorption of oxygen-containing sites on PDMS and fast zinc ion nanochannels in the negatively charged interlayer of MMT to achieve targeted-capture of zinc ions and ordered-deposition, thus inducing horizontally oriented Zn(002) deposition in the initial nucleation layer and providing a flat deposition site for the subsequently deposited metal. In the evolutionary stage of Zn, the PDMS/MMT (PMZn) interfacial layer can achieve a conformal contact with the anode due to the high dynamic adaptability and self-healing of the micro-crosslinking of Si-O-Si and B-O bonds. Consequently, PMZn@Cu||Zn offers higher coulombic efficiency(CE) (99.77%) and the PMZn@Zn anodes exhibit an ultra-long cycle life of 2000 h, more than 10 times that of bare zinc anodes. The stability of the high capacity of PMZn@Zn||MnO2 full cells far exceeds that of Zn||MnO2. This strategy provides an effective approach to develop a stable Zn metal anode for aqueous rechargeable Zn batteries.