Sustainable nitrogen-doped porous carbon with high surface areas prepared from gelatin for supercapacitors

Abstract

Gelatin, a renewable animal derivative composed of various proteins, was used as a precursor for nitrogen-doped porous carbon with high surface areas for supercapacitors for the first time. The preparation procedure is very simple, including the carbonization of gelatin under inert atmosphere, followed by NaOH activation of the carbonized char at 600 °C for 1 h. The porosity and surface chemistry of the carbon depend strongly on the weight ratio of NaOH/char, with the specific surface area and nitrogen content varying between 323 and 3012 m² g⁻¹ and between 0.88 and 9.26 at%, respectively. The unique microstructure and nitrogen functionalities enable the carbon to exhibit a high capacitance of up to 385 F g⁻¹ in 6 mol L⁻¹ KOH aqueous electrolytes, attributed to the co-contribution of double layer capacitance and pseudo-capacitance. It also shows excellent rate capability (235 F g⁻¹ remained at 50 A g⁻¹) and cycle durability, making it a promising electrode material for supercapacitors.