Nanofluidic electrolyte based on nitrogen doped reduced graphene oxide as an electrocatalyst for VO2+/VO2+ in vanadium redox flow battery

Vanadium Redox Flow Battery (VRFB) have garnered significant attention in recent years as a stationary energy storage system, yet its prevalence is hindered by sluggish electron transfer kinetics. Herein, we demonstrate the prospects of nanofluidic electrolyte based on nitrogen doped reduced graphene oxide (N-rGO) as an electro-catalyst for positive half-cell in VRFB. N-rGO with rich nitrogen functional group and structural defect is syn-thesized through improved Hummers' method, followed by thermal annealing in an inert atmosphere using an eco-friendly nitrogen precursor. The electrochemical kinetics of positive redox pair VO2+/VO2+is found to be improved significantly with nanofluidic electrolyte and were in proportion to the concentration of N-rGO. On comparison with base electrolyte, N-rGO (0.1 wt%) based nanofluidic electrolyte exhibited better electro-chemical reversibility, 35 % improvement in peak current density, reduced overpotential and charge transfer resistance by 23 % and 58 % respectively. The enhanced electrochemical performance may be attributed to the enhanced electrochemical surface area and electrical conductivity of N-rGO along with improved hydrophilicity of nanofluid. The present study proposes N-rGO based nanofluidic electrolyte as a potential candidate for effective electrocatalysis in VRFB.

Automated summary

In this study, nitrogen-doped reduced graphene oxide (N-rGO) was synthesized as an electro-catalyst for the positive half-cell in VRFB. The nanofluidic electrolyte based on N-rGO exhibited better electrochemical reversibility and improved performance in terms of current density, overpotential, and charge transfer resistance compared to the base electrolyte. The enhanced electrochemical performance was attributed to the increased electrochemical surface area, electrical conductivity of N-rGO, and improved hydrophilicity of the nanofluid.