Abstract: In alkaline zinc-iron flow batteries (AZIFBs), the non-ideal deposition behavior of zincate ions (Zn(OH)42-) readily induces the formation of zinc dendrites and “dead zinc”, severely compromising cycling stability and service life. In this study, 2-methylimidazole (2-Mel) was introduced as a functional additive to regulate zinc electrodeposition and enhance battery performance. Through coordination with zincate ions, 2-Mel induces uniform zinc deposition on the electrode surface and forms a stable adsorption layer, effectively suppressing dendrite growth and dead zinc formation. Morphological and crystallographic analyses (SEM and XRD) reveal that the presence of 2-Mel changes the dominant zinc growth orientation from the (101) plane, nearly perpendicular to the substrate, to the (002) plane, parallel to the substrate, thereby significantly improving zinc deposition morphology. Electrochemical characterization demonstrates that 2-Mel has minimal impact on zincate deposition kinetics but markedly reduces mass transport resistance and corrosion current, optimizing interfacial reactions at the zinc anode. Under optimized conditions, the AZIFB with 2-Mel achieves stable cycling over 1050 cycles at 80?mA?cm-2, exhibits excellent thermal adaptability from 25 to 55?°C, and delivers a peak power density of 1,133.7?mW?cm-2 at 80% state of charge. These results underscore 2-Mel as an efficient additive with significant potential for improving the electrochemical performance and durability of alkaline zinc-iron flow batteries.