Effect of alkaline organic electrolytes on electrochemistry of zinc electrode

Zn electrode suffers from poor electrochemical reversibility due to various parasitical reactions in alkaline aqueous electrolyte, like electrode passivation, shape change, dendrite generation and self-corrosion, arising from the interaction of Zn with solvent water. This paper reports the enhanced electrochemical performances of zinc in alkaline potassium hydroxide-ethylene glycol (KOH-EG) electrolytes without the participation of water. Cyclic voltammetric test shows that zinc electrode is not passivated in KOH-EG organic electrolyte but has good electrochemical reversibility. The concentration of KOH exerts influence on Zn's electrode potential and charge/ discharge performances with an optimum concentration of 4.5 M, boosting a 2.45 V MnO2-Zn full cell assembled with 4.5 M KOH-EG and 0.5 M H2SO4 + 0.1 M MnSO4 aqueous solution as anolyte and catholyte, respectively.