Effect of Electrolyte Concentration on Electrochemical Properties of Zinc Hexacyanoferrate Electrode in Zinc-Ion Batteries

Abstract

The aqueous rechargeable zinc ion battery (ARZIB) system has been actively studied in the field of energy storage. Prussian blue analogues (PBAs) are considered effective cathode materials in the ARZIB system. In our previous study, Zn(NO3)2 solutions of different concentrations were used as electrolytes in an ARZIB system with a zinc hexacyanoferrate (ZnHCF) electrode. And the effect of electrolyte concentration on the electrochemical performance was studied. In this study, the effect of electrolyte concentration was demonstrated through electrochemical tests and Raman analysis. Charge/discharge tests were conducted at different electrolyte concentrations. And electrochemical performance degradation was observed above a certain electrolyte concentration. This effect was due to the strong interaction between the zinc cations and the nitrate anions, confirmed by the Raman spectroscopy analysis of the Zn(NO3)2 electrolyte.