Universal electrolyte cooling strategy realizes high reversibility of zinc metal anodes

Low temperature operation is often perceived as detrimental due to sluggish reaction kinetics for energy storage systems. However, our investigation underscores a noticeable enhancement in the zinc (Zn) metal reversibility under such conditions. By delving into thermodynamics and kinetics, we demonstrated an electrolyte cooling (e. g. -20 degrees C) strategy that mitigates the inherent corrosiveness during transient period but also curtails the interaction of reactive species during the battery operations. As a proof concept in a strong-acid electrolyte, Zn metal manifest a reversibility approaching 99.66 % in challenging SUS substrate and 99.94 % in Cu substrate at low current density (e.g. 0.1 mA cm-2), typically plagued by harsh HER. Building on this, we demonstrated a stable Zn-MnO2 full cell at low temperatures over 500 cycles and achieved a high areal-capacity reaching 4.96 mAh cm-2. Additionally, the electrolyte cooling strategy demonstrates impressive universality, proving effective across a diverse range of electrolytes. This investigation provides pivotal insights into modulating the HER and augmenting Zn reversibility, shedding light for the development of aqueous Zn-based storage systems.