This study addresses the limitations of graphite felt (GF) in vanadium redox flow batteries (VRFBs), such as poor wettability, insufficient active sites, and low surface area. The researchers developed an ultra-homogeneous multiple-dimensioned defect engineering method using a molten salt system to modify GF. Specifically, NH4Cl and KClO3 were added to the system to create a porous N/O co-doped electrode (GF/ON). The KClO3 decomposed into O2 and O-containing functional groups, while NH4Cl served as a nitrogen dopant. This modification increased the surface area, active sites, and wettability of GF, enhancing its electrochemical catalysis for VO2+/VO2+ and V3+/V2+ reactions. The modified GF/ON electrode showed superior performance compared to pristine GF and other modified electrodes, with higher discharge capacity, energy efficiency, and stability during cycling. The enhanced performance is attributed to the increased active sites, surface area, and wettability, as well as the synergistic effect of N and O doping. The study demonstrates the potential of this ultra-homogeneous defect engineering method for preparing superior electrodes in VRFBs.This study addresses the limitations of graphite felt (GF) in vanadium redox flow batteries (VRFBs), such as poor wettability, insufficient active sites, and low surface area. The researchers developed an ultra-homogeneous multiple-dimensioned defect engineering method using a molten salt system to modify GF. Specifically, NH4Cl and KClO3 were added to the system to create a porous N/O co-doped electrode (GF/ON). The KClO3 decomposed into O2 and O-containing functional groups, while NH4Cl served as a nitrogen dopant. This modification increased the surface area, active sites, and wettability of GF, enhancing its electrochemical catalysis for VO2+/VO2+ and V3+/V2+ reactions. The modified GF/ON electrode showed superior performance compared to pristine GF and other modified electrodes, with higher discharge capacity, energy efficiency, and stability during cycling. The enhanced performance is attributed to the increased active sites, surface area, and wettability, as well as the synergistic effect of N and O doping. The study demonstrates the potential of this ultra-homogeneous defect engineering method for preparing superior electrodes in VRFBs.