Rapid Synthesis of Oxygen-Enriched Porous Carbon Through a Microwave Method and its Application in Supercapacitors

Abstract

In this study, a strategy for the rapid and simple preparation of porous carbon (PC) using the microwave method is proposed. Oxygen-rich PC is synthesized by microwave irradiation in air, where potassium citrate and ZnCl 2 serves as the carbon source and microwave absorber, respectively. ZnCl 2 achieves microwave absorption through dipole rotation, which uses ion conduction to convert heat energy in the reaction system. In addition, potassium salt etching improves the porosity of PC. The PC prepared under optimal conditions had a high specific surface area (902 m 2 ·g -1 ), and exhibits a significant specific capacitance ( 380 F·g  -1 ) in the three-electrode system at 1 A·g -1 .The energy and power densities of the symmetrical supercapacitor device based on PC-375W-0.4 are 32.7 W·h·kg -1 and 0.65 kW·kg -1 , respectively, at a current density of 1 A·g -1 . Even under 5000 cycles at 5 A·g -1 current density, the excellent cycle life retains 94% of its initial capacitance. This method can be easily extended to large-scale and low-cost preparation of carbon nanomaterials, which provides a novel method for the mass production of high-performance energy storage equipment.

Keywords: microwave synthesis, Zinc chloride, Potassium citrate, porous carbon, oxygen-rich, supercapacitor