Addressing thermodynamic Instability of Zn anode: classical and recent advancements

Abstract

Zn batteries receive substantial commendation, due to their inherent safety, environmental benignity and low toxicity. However, poor rechargeability of Zn anode have seriously hindered the applications of rechargeable Zn batteries. The challenges induced by thermodynamic instability of Zn in aqueous electrolytes include dendrites, passivation, corrosion (H2 evolution) and shape change. Since Zn anode is the critical aspect in determining the battery performance, cycle life, energy density and capacity retentions etc. The target of this review is to devote the prominent status to Zn metal anode by firstly explicating the previously studied Zn electrochemistry in different electrolyte systems like aqueous (acidic, alkaline, mildly acidic and neutral), non-aqueous (organic, ionic liquids) electrolytes, and then suggesting some ideas to amend Zn anode reversibility and stability. Because of higher thermodynamic Zn stability in organic electrolytes and recent promisingly improved performance of Zn metal anode, we mark organic electrolytes, particularly with intrinsic safe organic solvents as a promising research direction for high-performance zinc ion batteries (ZIBs).