High-Temperature Stability of Zn Anode in DES-3 Electrolyte for Long-Term Battery Cycling

In order to assess the stability of the Zn anode in aqueous and DES-3 electrolytes, Zn-Zn symmetric cells were constructed and subjected to long-term constant current cycling. Despite the challenging condition of a lower current, the zinc anode in the DES-3 electrolyte exhibited stable cycling for more than 1700 hours at a current density of 0.1mA cm−2. On the other hand, the cell utilizing the aqueous electrolyte experienced a rapid increase in overpotential and failed after 52 hours. Upon reaching a working temperature of 80℃, with a current density of 1 mA cm−2 and a deposition capacity of 1 mAh cm−2, the aqueous electrolyte demonstrated a rise in polarization voltage and experienced battery failure in less than 1500 minutes. This can be attributed to intensified parasitic reactions, especially the hydrogen evolution reaction (HER), within the battery at higher temperatures. These reactions resulted in battery swelling, device detachment, and a decline in battery performance. In contrast, the cell employing the DES-3 electrolyte exhibited stable cycling for over 5000 minutes. (Fig S).