期刊及卷期：
Surface and Coatings Technology, 第133385頁
摘要：
Molybdenum-doped nickel–cobalt oxide (NCO–Mo) nanowires were directly grown on graphite felt to construct high-performance electrodes for vanadium redox flow batteries (VRFBs). Morphological and structural characterizations (XRD, HAADF-STEM, XPS, XANES, and EXAFS) confirm a well-integrated nanowire coating with uniform elemental distribution and Mo incorporation into the NiCo2O4 host without detectable crystalline impurity phases. Mo incorporation induces oxygen vacancies (+4.75 percentage points) and modulates near-surface electronic states, which are expected to benefit interfacial charge transfer and provide abundant active sites for vanadium redox reactions. Electrochemical tests demonstrate that the optimized NCO–Mo3 electrode delivers an energy efficiency of 86.96% at 80 mA cm−2, 12.3 percentage points higher than pristine graphite felt (74.68%). Notably, it maintains strong performance over a wide current-density range (80–260 mA cm−2), achieving 63.46% efficiency at the maximum current density. The electrode also exhibits excellent durability over 250 charge–discharge cycles with coulombic efficiency above 97% and negligible performance decay (<0.2% per cycle). Mechanistically, oxygen-vacancy-mediated defect engineering reduces charge-transfer resistance, suppresses hydrogen evolution, and enhances intrinsic catalytic activity toward the VO2+/VO2+ redox reactions. These findings highlight oxygen-vacancy-regulated Mo doping as a general strategy for wide-current-density VRFB electrodes.
