Intrinsically microporous polymer-based hierarchical nanostructuring of electrodes: Via nonsolvent-induced phase separation for high-performance supercapacitors

The growing demands of next-generation applications for high power and energy sources necessitate advances in hierarchically porous carbon-based energy storage materials, which improve the overall kinetics of electrolytic reactions by providing efficient ion and electron transport pathways and facilitate electrolyte infiltration into the electrode during charging/discharging. Herein, we fabricate hierarchically structured porous carbon electrodes (cNPIM), prepared by solution casting of a polymer of intrinsic microporosity (PIM-1) followed by nonsolvent-induced phase separation and carbonization. The obtained material exhibits a considerable surface area (∼2100 m² g^-1), high electrical conductivity (150 S cm^-1), high specific capacitances (345, 235, and 195 F g^-1 in three-, two-electrode aqueous systems, and two-electrode organic systems, respectively) at 1 A g^-1, and an exceptional specific energy of 43.2 W h kg^-1 at a specific power of 1.25 kW kg^-1, featuring a pore size gradient in the surface normal direction.