Juxtaposing Reticulated Vitreous Carbon and Physicochemically Modified Graphite Felts as Anode Substrates for High Areal Capacity Soluble Lead Redox Flow Battery

Pristine normal Graphite felt (NGF) is physicochemically perforated followed by chemical treatment and collated with reticulated vitreous carbon (RVC) as anode substrate for soluble lead redox flow batteries (SLRFBs) to achieve areal capacity of 100 mAh cm −2 . Physicochemically modified graphite felt (PCGF) is employed as an anode substrate in the SLRFBs and its performance is compared with RVC. Contact angle measurements confirm the improved wettability of PCGF electrodes. Fourier transform infrared analysis reveals a reduced C–O content, while X-ray photoelectron spectroscopy studies show higher oxygen content in PCGF compared to NGF. Field-emission scanning electron microscopy shows that Pb metal predominantly deposits on the surface of NGF, whereas it penetrates through PCGF. Cyclic voltammetry suggests that NGF, PGF, and PCGF electrodes exhibit superior single-peak anodic stripping performance compared to RVC electrodes, which show poor two-step stripping. Galvanostatic cycling demonstrates that RVC electrodes exhibit initial coulombic efficiency of 94% that declines to 70% after 17 cycles. By contrast, NGF, PGF, and PCGF graphite felt electrodes maintain average coulombic efficiencies of 98%, 97%, and 98%, respectively, when charged and discharged at current density of 20 mA cm −2 , exhibiting stable performance. Current-potential data and self-discharge studies validate superior performance of PCGF electrodes.