Exploration of carbon nanoarchitectures with lower cost and excellent rate capability is of great importance, however, still remains a significant challenge. In the present work, a facile procedure for the fabrication of porous carbon nanocages (PCNCs) with a superior rate capability for supercapacitors has been developed. This approach is based on directly carbonization of sodium polyacrylate and subsequently chemical etching through a simple immersing-filtration-activation process. The extraordinary structures and morphologies of PCNCs has lots of structural advantages for supercapacitor applications. The supercapacitor assembled with the optimized sample can deliver a large specific capacitance (161 F/g at 1 A/g), superior rate capability (capacitance retention as high as 77.6% at 30 A/g), tiny IR drop (0.407 Vat 30 A/g). Furthermore, in view of the wide working voltage (2.7 V) and excellent rate capability, the energy densities can retain at 30.2 Wh/kg at a large power density of 20.3625 kW/kg. Remarkably, the as-assembled supercapacitor can light 11 red light-emitting diodes (LED, 1.5 V) in parallel highlighting its enormous potential for practical applications.