Sodium-Ion Insertion/Extraction Properties of Sn-Co Anodes and Na Pre-Doped Sn-Co Anodes

The electrochemical properties of Sn-Co were investigated to show the correlation between the cycle performance and the binders of the electrode component materials. Sn-Co electrodes with polyacrylic acid (PAA) exhibited a better cycle property (about 300 mAh/g up to 30 cycles) than those with polyvinylidene difluoride (PVdF). This better cycle property with PAA was due to the slight change in the volume of the electrode that occurred during cycling as revealed by in-situ light microscopy. In addition, Na pre-doping in Sn-Co electrodes improved the average coulombic efficiency from 95.4% to 99.9% at 2-10 cycles. (C) The Author(s) 2015. Published by ECS.