Effects of carbon surface area on performance of lithium sulfur battery cathodes

The effect of carbon surface area on capacity is investigated in cathodes for lithium sulfur batteries. Carbon additives help overcome the low electrical conductivity of sulfur. Cathodes were prepared at 30wt% sulfur on different activated carbons having unloaded BET surface areas of 1200–3200m2/g. Sulfur utilization ranged from 33% to 83% of the theoretical capacity (1672mAh/g) with a strong correlation to the accessible pore volumes having pore widths between 1 and 5nm. Additionally, cathodes prepared at 12.5–68wt% on an activated carbon having unloaded BET surface area of 3200m2/g showed excessive sulfur loading provided little additional capacity.