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 N-2 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 N-2 sorption in sucrose-derived carbon. (C) 2014 Elsevier Ltd. All rights reserved.