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

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 m 2 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.