Synergistic Enhancement of Capacitive Performance in Porous Carbon by Phenolic Resin and Boric Acid

The study of pore structure regulation methods has always been a central focus in enhancing the capacitance performance of porous carbon electrodes in lithium-ion capacitors (LICs). This study proposes a novel approach for the synergistic regulation of the pore structure in porous carbon using phenol-formaldehyde (PF) resin and boric acid (BA). PF and BA are initially dissolved and adsorbed onto porous carbon, followed by hydrothermal treatment and subsequent heat treatment in a N₂ atmosphere to obtain the porous carbon materials. The results reveal that adding BA alone has almost no influence on the pore structure, whereas adding PF alone significantly increases the micropores. Furthermore, the simultaneous addition of PF and BA demonstrates a clear synergistic effect. The CO₂ and H₂O released during the PF pyrolysis contribute to the development of ultramicropores. At the same time, BA facilitates the N₂ activation reaction of carbon, enlarging the small mesopores and aiding their transformation into bottlenecked structures. The resulting porous carbon demonstrates an impressive capacitance of 144 F·g^-1 at 1 A·g^-1 and a capacity retention of 19.44% at 20 A·g^-1. This mechanism of B-catalyzed N₂-enhanced mesopore formation provides a new avenue for preparing porous carbon materials. This type of porous carbon exhibits promising potential for applications in Li-S battery cathode materials and as catalyst supports.