Microporous and Grain-Sized Design of High-Yield Porous Carbon Materials by Using Potassium Acetate and P-Phenylenediamine

Porous carbon with large specific surface area (SSA) and high porosity is an ideal electrode material for supercapacitors. However, the traditional KOH activation remains several barriers, such as low yield, high corrosion, and pollution. In this paper, nitrogen-doped (1.68% N content) porous carbon (C-PKAC1.5) with high yield (26.3%), large SSA (2820.65 m2/g) and uniform size was prepared from p-phenylenediamine (PDA) in one-pot by using potassium acetate (KAc) instead of KOH. Throughout the process, KAc played the vital roles: 1) KAc could form hydrogen bonding network with PDA and mixed homogeneously, while PDA providing nitrogen dopant and carbon source. 2) After polymerization, the KAc lamellae reconstituted and achieved geometric partition of polymer matrix, left diffusion micro-tunnels and provided homogenized size of carbon particles at the following stage. 3) During activation, KAc melt and diffused into polymer matrix through micro-tunnels and converted to K2CO3 to activate from inside to outside, while avoiding the low yield for conventional activation from outside to inside. The supercapacitor assembled for C-PKAC1.5 exhibits high specific capacitance of 25.17 F/g and 82.77% of capacitance retention after 30,000 cycles, and achieves a high energy density of 8.29 Wh/L at a power density of 199.25 W/L.