N-doped graphitized porous carbon derived from N-rich polymer for improved supercapacitor performance

Abstract

Porous carbons with the large specific surface area, high electrical conductivity as well as abundant heteroatom doping are regarded as a promising candidate for supercapacitor applications. In this report, a facile potassium ferrate (K₂FeO₄) activation strategy is adopted to transform the N-rich Schiff-based polymer into N-doped graphitized porous carbons (NGPCs) by the synchronous activation and graphitization. The optimized NGPC-700-1 sample delivers a delightful capacitance of 322.7 F g⁻¹ at 0.5 A g⁻¹ and an excellent rate capability (79.1% capacitance retained at 50 A g⁻¹) in 6 M KOH due to the unique laminated and porous structure with the large surface area (2123.7 m² g⁻¹), high porous volume (1.30 cm³ g⁻¹) and abundant N/O dopant (6.20/8.20 at%). Moreover, the assembled symmetric supercapacitor achieves a high energy density of 21.5 W h kg⁻¹ at the power supply of 445.5 W kg⁻¹ in 1 M Na₂SO₄ electrolyte. Therefore, NGPCs derived from one-step activation/graphitization of N-rich polymer represent a promising route for preparing porous carbon materials with the high charge storage capacity and rate capability in the energy storage.