3D O/N/S Tridoped Honeycomb-Like Porous Carbon with Enhanced Performance for High-Mass Loading Supercapacitors

Abstract

To satisfy the practical needs of the sustainability and industrialization of supercapacitors, it is essential to maintain good electrochemical performance at high mass loading (>10 mg cm⁻²). Herein, a unique 3D O/N/S tridoped honeycomb-like porous carbon is successfully prepared from chitosan as carbon precursor and L-cysteine as sulfur source using gelation pretreatment and high-temperature pyrolysis methods. Chitosan and L-cysteine hierarchical porous carbons (CL-HPC-3:1) display rich O/N/S heteroatoms content, high specific surface area, (2806 m² g⁻¹), interconnected hierarchical porous structure, good conductivity (0.23 Ω cm⁻¹; 4.35 S cm⁻¹), and strong wettability (the contact angle is 19°), which enable fast electron/ion transport and afford additional capacitance. Importantly, CL-HPC-3:1 (3:1 represents the mass ratio of chitosan to L-cysteine.) can maintain excellent electrochemical performance at mass loading of 12.2 mg cm⁻², which has high specific capacitance (298.36 F g⁻¹ at 0.1 A g⁻¹), high area capacitance (3.64 F cm⁻² at 0.1 A g⁻¹), low-open-circuit voltage attenuation rate (21.63 mV h⁻¹), high voltage retention (78.54%), and remarkable cyclic stability (92.06% capacitance retention after 20 000 cycles). This work demonstrates the successful conversion of chitosan into the sustainable and high-performance electrode materials and also develops a valuable utilization way for chitosan.