Green and Facile Synthesis of N/S Codoped Hierarchical Porous Carbon from Gelatin for Advanced-Performance Supercapacitors

The effective promotion of practical applications for supercapacitors requires the utilization of available natural resources as sustainable precursors for the development of high-performance electrodes. Furthermore, addressing the challenges of inferior specific capacitance, limited energy density, and poor rate capacity in supercapacitors largely relies on the reasonable design of the porosity frameworks and the surface properties of carbon materials. Herein, we propose a sustainable and facile avenue for synthesizing N/S codoping three-dimensional (3D) interrelated porous carbon utilizing the pyrolysis of gelatin (Gel) impregnated with toxic dye (water contaminant methylene blue, MB). The synthesized Gel/MB–2–700 retains a relatively large specific surface area (2042.98 cm2 g–1), elevated N (11.25%) and moderate S (0.7%) contents, a high density of micropores, and proper mesoporous distribution, all of which are essential to boosting ion diffusion and enhancing capacitive performance. As a result, Gel/MB–2–700 has been confirmed to be an exceptional electrode for supercapacitors, displaying a satisfactory specific capacity of 316 F g–1 at 1 A g–1 and a superior rate property of 80.8% at 10 A g–1 in a three-electrode system. The assembled symmetric device (Gel/MB–2–700//Gel/MB–2–700) exhibits superior cycling durability of 99.03% and Coulombic efficiency of 98.6% after 10 000 cycles at 2 A g–1. Remarkably, an exceptional energy density can reach 10.35 Wh kg–1 at 500 W kg–1. Our study offers a promising and eco-friendly avenue for synthesizing multidoped hierarchical porous carbon electrode materials for low-cost and high-performance supercapacitors.