A capacitance increase phenomenon is observed for MoO₃electrodes synthesizedviaa sol-gel process in the presence of dopamine hydrochloride (Dopa HCl) as compared to α-MoO₃electrodes in 5M ZnCl₂aqueous electrolyte. The synthesis approach is based on a hydrogen peroxide-initiated sol-gel reaction to which the Dopa HCl is added. The powder precursor (Dopa)_xMoO_y, is isolated from the metastable gel using freeze-drying. Hydrothermal treatment (HT) of the precursor results in the formation of MoO₃accompanied by carbonization of the organic molecules; designated as HT-MoO₃/C. HT of the precipitate formed in the absence of dopamine in the reaction produced α-MoO₃, which was used as a reference material in this study (α-MoO₃-ref). Scanning electron microscopy (SEM) images show a nanobelt morphology for both HT-MoO₃/C and α-MoO₃-ref powders, but with distinct differences in the shape of the nanobelts. The presence of carbonaceous content in the structure of HT-MoO₃/C is confirmed by FTIR and Raman spectroscopy measurements. X-ray diffraction (XRD) and Rietveld refinement analysis demonstrate the presence of α-MoO₃and h-MoO₃phases in the structure of HT-MoO₃/C. The increased specific capacitance delivered by the HT-MoO₃/C electrode as compared to the α-MoO₃-ref electrode in 5M ZnCl₂electrolyte in a −0.25–0.70 V vs. Ag/AgCl potential window triggered a more detailed study in an expanded potential window. In the 5M ZnCl₂electrolyte at a scan rate of 2 mV s⁻¹, the HT-MoO₃/C electrode shows a second cycle capacitance of 347.6 F g⁻¹. The higher electrochemical performance of the HT-MoO₃/C electrode can be attributed to the presence of carbon in its structure, which can facilitate electron transport. Our study provides a new route for further development of metal oxides for energy storage applications.