Sustainable Graphitic Carbon Materials from Biogas as Anodes for Sodium-Ion Batteries

Novel graphitic materials of renewable origin, biogas-derived carbon nanofibers (BCNFs), are investigated as anodes for sodium-ion batteries in a glyme-based electrolyte. These materials show a unique combination of electrochemical properties, including suitable capacity (similar to 100 mAh g(-1)), high rate capability, excellent cycle stability and coulombic efficiency as well as long cycle life (similar to 6000 cycles up to 7.5 A g(-1)) which make them adequate candidates for this application. The sodiation of BCNFs occurs through different combinations of diffusion-controlled intercalation and capacitive intercalation processes. Overall, the quantitative contribution of the capacitive current to the total stored sodium in BCNF electrodes is noteworthy (28-71%), which account for their ultrahigh rate performance, comparable to that of supercapacitors, because of the improvement of the transportability of the Na+ ions through the graphene layers. (C) 2019 The Electrochemical Society.