fig4

Figure 4. Performance of assembled Zn/TEMPO RFB with 0.5 M ZnCl₂ (with and without 0.025 M SPr-Bpy) in anolyte and 0.5 M TMAAcNH-TEMPO in catholyte. 1 M KCl was used as supporting electrolytes. (A) Diagram and mechanism of Zn/TEMPO RFB with SPr-Bpy. (B) Long-term cycling of the battery with an areal capacity of 24.4 mAh cm^-2. The battery was cycled galvanostatically at 20 mA cm^-2 and ended with a potentiostatic hold until the magnitude of the current density fell below 3.0 mA cm^-2. Inset: Voltage-capacity curve of the RFBs with and without SPr-Bpy. (C) Comparison of the battery performance of this work with that of other reported Zn-based RFBs. Key parameters of battery capacity retention and areal capacity are compared.