Electrochemical properties of Sn-Co electrode with various kinds of binder materials for sodium ion batteries

Discharge-charge properties of Sn-Co anode materials with various kinds of binders [polyvinylidene difluoride (PVdF), polyacrylic acid (PAA), sodium polyacrylate (PAANa), sodium carboxymethyl cellulose (CMC), and polyimide (PI)] for sodium ion batteries were investigated to determine the correlation between cycle performance and the properties of electrode with binder. Sn-Co electrodes with PAA or CMC binders exhibited better cycle properties (discharge capacities of more than 400 mAh/g up to 20 cycles) than with PVdF, PAANa, or PI. These cycle properties with PAA or CMC were due to smaller changes in the electrode volume that occurred during cycling, as revealed by in situ light microscopy.