Phenol-formaldehyde-resin-based activated carbons with controlled pore size distribution for high-performance supercapacitors

Carbon-based materials with a controlled pore size distribution are highly desirable to achieve fast diffusion of electrolytes and enhance supercapacitor performance. Here, we report a method to effectively control porosity of the phenol formaldehyde (PF) resin-based carbons along with pore volume and pore size distribution using a combined metal templating and physical/chemical activation approach. The combined metal templating and physical/chemical activation approach allows the precise control of the pore size of the carbons. PF resin synthesized by suspension polymerization was used as a carbon source and metal ions (Fe+ and Zn+) were used as templating agents. The pore size could be superbly tuned in the 2-50 nm range by varying the metal ion. Carbonization and CO2 activation of the metal-embedded PF resins yielded carbon microparticles (M-CMP), which turned into carbon microparticles (M-CMP-S) having mesopores in the range of 35-51 nm by sonication and KOH activation. The specific capacitances of Fe-CMP-S and Zn-CMP-S were as high as 132 and 152 F g (58 and 74 F cm(-3)) in ionic liquid electrolyte with energy densities of 56 and 64 Wh kg(-1), respectively. In organic electrolyte, the Zn-CMP-S showed the specific capacitance of 136 F g(-1) with a maximum power density of 709 kW kg(-1). Adjustable pore size of the M-CMP-S facilitated the diffusion of electrolyte ions into the electrode, thereby achieving supercapacitor with high energy and power density.