Gelatin/Carboxymethyl Cellulose-Based Quasi-Solid-State Supercapacitors

Gelatin is a promising biomass material for supercapacitors. In this article, carboxymethyl cellulose (CMC) and gelatin are used as raw materials to form soluble composite condensates as precursors for carbon electrodes as well as gel electrolytes. By an environmentally friendly method, N, O, and P multidoped three-dimensional porous carbon named CMC-GL-700 with a large specific surface area of 613.62 m² g^–1 and a pore volume of 0.3672 cm³ g^–1 is obtained. Due to these advantages, the porous carbon electrode delivers a large specific capacitance of 340 F g^–1 at 1 A g^–1 and good cycle stability with 92.5% capacity retention after 10000 cycles. Moreover, all CMC-GL-based quasi-solid-state supercapacitors, made with CMC-GL-700 as an electrode and CMC/GL hydrogel as a gel electrolyte, exhibit a high energy density of 39.16 Wh kg^–1 at a power density of 414.64 W kg^–1.