Supercapacitors hold great promise as energy storage devices due to their rapid charge-discharge rates and exceptional durability. However, their low energy density has constrained their practical applications. In this study, we synthesize carbon-nanotubes@MnO2-nanosheets core-shell nanotube arrays on carbon cloth to enhance the volumetric capacitance of supercapacitors. Our method utilizes radially grown ZnO nanowires as sacrificial supports to fabricate carbon-nanotube-supported MnO2 structures. The resulting electrode exhibits a high specific capacitance of 0.52 F cm⁻² at 2 mV s⁻¹ and demonstrates excellent rate performance, maintaining a capacitance of 0.25 F cm⁻² at a high scan rate of 100 mV s⁻¹. The asymmetric solid-state supercapacitor, constructed using this composite and paired with a carbon electrode, displays outstanding electrochemical performance, including a voltage window of up to 1.8 V, a high volumetric energy density of 2.85 mWh cm⁻³, and a power density of 453.8 mW cm⁻³. These findings provide valuable insights for the development of next-generation energy storage devices, capable of meeting the growing demands for portable and flexible electronics.