Superior capacitive performance of micropore-dominant porous carbon derived from biomass wastes

Abstract

A series of porous carbon materials with rich O-containing groups are facilely fabricated from the poplar catkin biomass wastes. The optimal KAPC-700-2, which is prepared under the conditions of calcination temperature 700 °C and a mass ratio of 1:2 for the pre-carbonized carbon to activation agent (K2CO3), possesses a micropore-dominant porous network. Benefitting from the hierarchical porous network with a large specific surface area (1410 m2 g−1) and high O-doping amount (11.99 at.%), KAPC-700-2 displays excellent capacitive performance. The corresponding specific capacitance is 278.0 F g−1 at 1.0 A g−1 in the three-electrode system, as well as remarkable rate capability. The energy density in the assembled symmetrical devices (40.5 Wh kg−1 at 0.27 kW kg−1) is superior to many previous results. Other than that, KAPC-700-2 exhibits high cycling stability with a 105.8% capacitance retention in the 30,000th charge/discharge cycle at 1.0 A g−1. Our work offers a good strategy to produce porous carbon from annoying bio-wastes for advanced electrochemical energy storage devices.