Zinc Chloride-Activated N-Doped Super-Activated Carbon Derived from ZIF-8 with Optimized Pore System for Electrochemical Supercapacitor with Enhanced Energy Density

Nitrogen- and oxygen-doped high specific surfaces of activated carbon with an optimized pore system have been obtained by the method of calcination at 1000°C, using ZIF-8 as the precursor. The ZnCl 2 is as the activating agent, which is reduced to Zn 0 by the carbon in the precursor. And the specific surface area of activated carbon can reach up to 2569 m 2  g −1 . This is comparable to the specific surface area of activated carbon produced with KOH as the activating agent. The N 2 isothermal adsorption–desorption at 77 K indicates that the specific surface area of N-doped super-activated carbon increases a little to 2838 m 2  g −1 , when the urea has been incorporated into the precursor as extra an nitrogen source. Interaction between N- and O-doped carbon and K + ions in KOH is illustrated by the corresponding density function theory (DFT), and the electron cloud between K and the carbon material is simulated. The electrochemical measurements were conducted in 6 M KOH and 1 M Na 2 SO 4 , which confirms that nitrogen and oxygen doping has a significant increase in specific capacitance. The super-activated carbon with an optimized pore system possesses excellent electrochemical performance, which shows good application prospects for energy storage.