The sluggish diffusion kinetics of metal ions and irreversible structural transition of electrode materials lead to serious decay of electrochemical performance. In this work, a “one-for-three” strategy is demonstrated to engineer commercial MoO₃ nanopowders by adjusting the morphology, coating a thin layer of conductive PANI and introducing oxygen vacancy through a simple one-step hydrothermal process. Benefiting from the synergistic effects of enhanced charge transfer kinetics, improved conductivity and robust structural stability, the optimized MoO₃ nanobelts show excellent performance in proton storage. The MoO₃ electrode delivers a record-high performance of 1307.4 F g⁻¹ (236.1 mA h g⁻¹) at 1.0 A g⁻¹, excellent rate capability with a capacitance retention of 55.3% at 50.0 A g⁻¹, and stable cycling performance with a capacitance retention of 95.5% after 6000 cycles. Furthermore, the redox reaction mechanism of the MoO₃ electrode in proton battery has been revealed. The fabricated P100-MoO₃//NAC proton storage hybrid device shows a maximum energy density of 43.3 W h kg⁻¹ at 800 W kg⁻¹ and noteworthy cycling stability. This novel design sheds light on the improved electrochemical kinetics in the energy storage of MoO₃-based electrodes with different electrolytes.