Abstract: Magnesium-based anode materials have attracted significant attention in the energy storage domain because of their high theoretical capacities and low electrochemical potentials. However, in conventional electrolyte systems, magnesium metal electrodes dynamically generate an ion-blocking surface layer, resulting in prominent voltage polarization, which severely limits their practical applications. In this study, ZIF-8/carbon nanotubes (CNTs) coatings were used to modify the anodes of magnesium batteries. Compared with the unaltered magnesium battery, the voltage lag time of the ZIF-8/CNTs coating was shortened from 4 s before modification to 0.26 s, and the battery impedance was lowered by two orders of magnitude. The duration of the discharge platform was increased from 4 h before modification to 6–10 h, the anode utilization rate was more than doubled, and the specific energy density was significantly enhanced compared with the battery before modification. The mechanism indicates that the ZIF-8/CNTs coating can limit the infiltration of corrosive substances, extend their transmission path, and offer more effective protection to the magnesium anode. The incorporation of CNTs improves the conductivity of the battery, and it significantly improves the electrochemical performance of the magnesium battery.