(173ac) Preparation of Carbon Electrodes from Food Waste for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are promising as the next generation of batteries. Sodium is a low cost, abundantly available element and has shown rapid rechargeability. Unlike lithium-ion batteries, which uses graphite as an anode material, SIBs can use hard carbon. Hard carbon is the amorphous carbon that cannot be graphitized even at more than 3000°C, can capture and store more sodium ions. Therefore, hard carbon that can perform well as SIB anode was desirable. More importantly, it should be preferable if it can be produced from sustainable materials. In this study, we aim to produce food waste derived hard carbon via heavy bio-oil with supercritical organic solvent treatment and analyze the fundamental characteristics of the produced hard carbon. The food wastes were converted into heavy bio-oils by heating with organic solvent such as methanol, ethanol, and acetone under supercritical condition. The bio-oils collected were solidified into carbonaceous material through vacuum heating. Finally, the carbonaceous materials were produced through activation process. The hard carbons were characterized by analyses such as proximate and ultimate analysis, FTIR, BET, TGA, ICP-OES, SEM, and cyclic voltammetry. The effects of different types of organic solvent on their structures and electrochemical performances were discussed based on the analytical results.