Electrode Materials for Practical Rechargeable Aqueous Zn-Ion Batteries: Challenges and Opportunities

Rechargeable zinc-ion batteries (ZIBs) based on near-neutral aqueous electrolytes have been actively researched in recent years as an alternative large-scale stationary storage device because of their outstanding merits in energy density, safety, cost, and environmental impact. Although remarkable materials advancements have been reported recently, particularly in the area of Zn-ion-storing cathodes, the commercialization course of ZIBs is still being hindered by several key technical issues such as capacity, degradation, self-discharge, etc. Recognizing that there are ample Reviews on ZIBs in the literature, the focus of this article is to specifically address the current development and critical challenges in ZIB electrodes and provide candid opinions for future commercialization of ZIBs. The Review starts with a brief introduction to ZIBs and their unique advantages in stationary energy storage, and then moves onto the current Zn-ion storage mechanisms, progress and issues associated with cathodes and anodes. Finally, the Review is concluded with perspectives and directions of future ZIB development.