Aromatic amines serve as monomers to produce conducting polymers by electropolymerization with good energy storage properties. However, their poor water solubility limits their electropolymerization processes. The copolymer of 1,5-diaminonaphthalene and o-phenylenediamine (PDAN-co-oPD) was synthesized for the first time using Triton X-100-assisted electropolymerization on a carbon cloth substrate. The energy storage mechanism of the material was investigated using X-ray photoelectron spectroscopy and scanning electron microscopy, where both Zn2+ and H+ were involved in the charge storage process in H2SO4 and ZnSO4 aqueous electrolytes. PDAN-co-oPD delivers specific capacities of 160.31 and 307.37 mAh g-1 in 1 M H2SO4 and 1 M ZnSO4 at 0.5 A g-1, respectively, along with high stability (88.5 and 94.7% capacity retention at 10 A g-1 after 3000 cycles in 1 M H2SO4 and 1 M ZnSO4, respectively). In addition, an aqueous zinc-ion electrochemical energy storage device was assembled, which exhibits a specific energy of 68.06 Wh kg-1 at a charging and discharging rate of 0.5 A g-1. These results show that PDAN-co-oPD can serve as an energy storage material to store charge in aqueous electrolytes.