Secondary High-Temperature Treatment of Porous Carbons for High-Performance Supercapacitors

Supercapacitors are extensively used in urban rail transit, electric vehicles, renewable energy storage, electronic products, and the military industry due to its long cycle life and high power density. Porous carbon materials are regarded as promising anode materials for supercapacitors due to their high specific surface areas and well-developed pore structures. However, the over-developed pore structure often results in poor conductivity and reduced cycle stability due to the destruction of a carbon skeleton. Herein, we introduce an advanced strategy for preparing porous carbon with high specific surface areas (3333 m2 g−1), high electrical conductivity (68.6 S m−1), and fast ion transport channels through secondary high-temperature carbonization treatment. As a result, the fabricated porous carbon anode delivers a high specific capacitance (199.2 F g−1 at 1 A g−1) and outstanding rate performance (136.3 F g−1 at 20 A g−1) in organic electrolyte. Furthermore, the assembled symmetrical supercapacitor achieves an energy density of 43.2 Wh kg−1 at 625.0 W kg−1, highlighting the potential of a secondary high-temperature carbonization strategy in practical applications.