Electrochemical Characterization of Charge Storage at Anodes for Sodium-Ion Batteries Based on Corncob Waste-Derived Hard Carbon and Binder

Sodium-ion batteries (SIBs) represent a potential alternative to lithium-ion batteries in large-scale energy storage applications. To improve the sustainability of SIBs, the utilization of anode carbonaceous materials produced from biomass and the selection of a bio-based binder allowing an aqueous electrode processing are fundamental. Herein, corncobs are used as raw material for the preparation of hard carbon and it is also used as cellulose sources for the synthesis of carboxymethyl cellulose (CMC) binder. The corncob-derived electrodes deliver a high discharge capacity of around 264 mAhg−1 at 1 C (300 mAg−1), with promising capacity retention (84 % after 100 cycles) and good rate capability. Additionally, this work expands the fundamental insight of the sodium storage behavior of Hard Carbons through an electrochemical approach, suggesting that the reaction mechanism is controlled by capacitive process in the sloping voltage region, while the diffusion-controlled intercalation is the predominant process in the low-voltage plateau.