Nitrogen and Sulfur Codoped Porous Carbon Directly Derived from Potassium Citrate and Thiourea for High-Preformance Supercapacitors

Wang Zhang, Xin Huo Xusen Li, Sumin Park, Liwei Lin, Sang Yoon Park, Guowang Diao, and Yuanzhe Piao
Langmuir 38(33), 10331(2022)
DOI:10.1021/acsaem.2c01863

Abstract

By introducing a heteroatom into carbon material, an
effective improvement in capacitance can be realized owing to surface
oxidation and reduction reactions of pseudocapacitors. Herein, a simple
one-pot carbonization activation method was proposed to convert
potassium citrate into three-dimensional interconnected porous carbon
(PC). Then, an effective double heteroatom doping method by thiourea
was used to prepare nitrogen−sulfur-doped PC (N,S-PC). This porous
structure facilitates the storage of a large number of ions and reduces
their diffusion path. The synthesized N,S-PC nanomaterial has a
capacitance of 674 F/g at 1 A/g in a 1 M H2SO4 electrolyte, can retain
94.41% of the initial capacitance after 10 000 cycles at 5 A/g, and has a
long cycle life. More importantly, a symmetric supercapacitor assembled with this material can exhibit an energy density of up to
32.6 (W·h)/kg at a high-power density of 750 W/kg. This is due to the high performance of N,S-PC in supercapacitor electrode materials.