fig4

Figure 4. Comparative cell performance of alkaline Fe/S RFBs with pristine CF and CuS-WA/CF anodes. (A) Representative charge-discharge curves at 40 mA cm^-2. (B) Polarization curves and the corresponding power density curves derived from them. (C) GITT curves. (D) Rate capability tested at progressively increasing current densities from 20 to 100 mA cm^-2. (E) Charge-discharge profiles of CuS-WA/CF-based cell across all tested current densities. (F) Charge-discharge profiles of pristine-CF-based cell across all tested current densities. All measurements shown in this figure were performed using 20.0 mL of a 0.8 M [Fe(CN)₆]^4- catholyte containing 0.4 M K₄[Fe(CN)₆], 0.4 M Na₄[Fe(CN)₆], and 1.0 M KOH, together with 60.0 mL of an anolyte containing 2.0 M K₂S and 1.0 M KOH.