Revisiting recent and traditional strategies for surface protection of Zn metal anode

Aqueous rechargeable Zn batteries have gathered supreme significance and importance in the recent times as promising energy storage devices. Zn batteries possess prodigious potential for safer and large-scale energy storage applications. However, the critical challenges associated with both Zn anode and cathode adversely affects their widespread commercialization that needs urgent methodologies to tackle these issues governed by thermodynamic instability of Zn anode in traditional aqueous electrolytes. The water induced unwanted side reactions include Zn dendrites, corrosion, shape change, passivation, H2 evolution that leads to poor Zn utilization and reversibility. Surface engineering of Zn anode through artificial protective layers/coatings is an emerging and promising research direction towards stabilization of Zn metal anodes. In this review, we summarize briefly the critical issues of Zn anode in aqueous environment and then switching to the up-to-date developments in surface coatings for Zn anode, with comprehensive explanations of their working principles. This review will provide latest and summarized literature for Zn battery community assisting them to design novel Zn anode protective approaches.