Bio‐inspired and Eco‐friendly Synthesis of 3D Spongy Meso‐Microporous Carbons from CO<sub>2</sub> for Supercapacitors
Ao Yu, Guoming Ma, Jintian Jiang, Yajing Hu, Mingming Su, Wangtao Long, Shixin Gao, Hsien‐Yi Hsu, Ping Peng, Fangfang Li
Abstract
Abstract Inspired by the spongy bone structures, three‐dimensional (3D) sponge‐like carbons with meso‐microporous structures are synthesized through one‐step electro‐reduction of CO 2 in molten carbonate Li 2 CO 3 −Na 2 CO 3 −K 2 CO 3 at 580 °C. SPC4‐0.5 (spongy porous carbon obtained by electrolysis of CO 2 at 4 A for 0.5 h) is synthesized with the current efficiency of 96.9 %. SPC4‐0.5 possesses large electrolyte ion accessible surface area, excellent wettability and electronical conductivity, ensuring the fast and effective mass and charge transfer, which make it an advcanced supercapacitor electrode material. SPC4‐0.5 exhibits a specific capacitance as high as 373.7 F g −1 at 0.5 A g −1 , excellent cycling stability (retaining 95.9 % of the initial capacitance after 10000 cycles at 10 A g −1 ), as well as high energy density. The applications of SPC4‐0.5 in quasi‐solid‐state symmetric supercapacitor and all‐solid‐state flexible devices for energy storage and wearable piezoelectric sensor are investigated. Both devices show considerable capacitive performances. This work not only presents a controllable and facile synthetic route for the porous carbons but also provides a promising way for effective carbon reduction and green energy production.