All carbon electrodes derived from semi-coke for electrochemical energy storage devices

With the developments of electrochemical energy storage devices, various natural and artificial carbonaceous materials have been explored as electrodes. In the work, two carbonaceous materials, activated semi-coke (ASC) and graphitized semi-coke (GSC), are prepared from cost-effective semi-coke. A variety of devices were assembled using as-synthesized ASC and GSC as electrodes, and their electrochemical properties are elucidated. It has been demonstrated that the GSC has impressive storage capabilities of anion and cation. The porous ASC shows good ion diffusion, large specific surface area, and decent capacitance. Thus, the as-studied symmetric ASC//ASC and asymmetric ASC//GSC and GSC//ASC devices deliver simultaneously manifest power and energy densities. This work provides general approach to utilize the cost-effective semi-coke in lithium ion-based secondary batteries and supercapacitors.