Research on the Performance of Zinc Ferrocyanide Positive Electrode Material for Zinc Ion Batteries
Zinc ferricyanide(ZnHCF),as a cathode material for aqueous zinc-ion batteries,possesses a high discharge platform and moderate theoretical specific capacity,showing significant potential for development.In this paper,ZnHCF was prepared via a room temperature coprecipitation method using potassium ferricyanide and zinc sulfate as raw materials.XRD analysis indicates that the diffraction peaks of ZnHCF conform to the standard card JCPDS No.25-1022,with diffraction peaks located at 16.2°,19.6°,and 24.4° corresponding to the(200),(004),and(300)crystal planes of ZnHCF,respectively,indicating sharp peaks which suggest good crystallinity of ZnHCF.FTIR analysis shows a characteristic peak of ZnHCF at 497.4 cm-1,while the peak at 1614.1 cm-1 corresponds to the C-N stretching vibration in Fe-CN-Zn.SEM analysis reveals that ZnHCF exhibits a granular structure with particle sizes ranging from 200 to 500 nm.Electrochemical tests were conducted using ZnHCF as the cathode,zinc as the anode,and aqueous solutions of ZnSO4 or Na2SO4 as electrolytes.The results show that the battery using saturated ZnSO4 electrolyte has a platform voltage around 1.8 V,achieving a maximum charge/discharge specific capacity of up to 120 mAh/g,with efficiency stably within the range of 90％to 100％,demonstrating optimal performance.The oxidation peak in the CV curve is observed at approximately 1.8 V(vs.Zn/Zn2+),while the reduction peak is around 1.6 V(vs.Zn/Zn2+).EIS test results indicate that after charge/discharge testing,ZnHCF displays two semicircles,suggesting an increase in charge transfer resistance.
zinc ferricyanideroom temperature coprecipitation methodcathode material for zinc-ion batteriesPrussian blue
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