<p>Manganese dioxide (MnO₂) has attracted much attention for supercapacitor application owing to its wide potential window and high theoretical capacitance. In this study, the nanoporous Ag powder was prepared by a two-step dealloying method using Ag₂₀Zn₈₀ alloy as a precursor, and then the nanoporous Ag/MnO₂ (NP-Ag/MnO₂) composite was constructed without the addition of conductive agents for use as an electrode material of supercapacitor. The optimized NP-Ag/MnO₂ composite exhibits a specific capacitance of 308 F g⁻¹ at a scan rate of 5 mV s⁻¹, while that is as low as 127 F g⁻¹ for the pristine MnO₂. Moreover, the capacitance retention of NP-Ag/MnO₂ composite electrode reaches 87.2% after 1000 cycles at 4 A g⁻¹, exhibiting a better cycling stability. The enhanced electrochemical performance of NP-Ag/MnO₂ composite primarily stems from the fact that nanoporous Ag provides both the three-dimensional conductive network and spatial confinement effect for the charge and discharge of MnO₂. Overall, this investigation gives a relatively simple and efficient method to synthesize the Mn-based electrode material with enhanced properties for supercapacitor.</p>