Predicting capacity of hard carbon anodes in sodium-ion batteries using porosity measurements

We report an inverse relationship between measurable porosity values and reversible capacity from sucrose-derived hard carbon as an anode for sodium-ion batteries (SIBs). Materials with low measureable pore volumes and surface areas obtained through N2 sorption yield higher reversible capacities. Conversely, increasing measurable porosity and specific surface area leads to sharp decreases in reversible capacity. Utilizing a low porosity material, we thus are able to obtain a reversible capacity of 335 mAh g−1. These findings suggest that sodium-ion storage is highly dependent on the absence of pores detectable through N2 sorption in sucrose-derived carbon.