Use of submicron carbon filaments in place of carbon black as a porous reduction electrode in lithium batteries with a catholyte comprising bromine chloride in thionyl chloride

Submicron carbon filaments used in place of carbon black as porous reduction electrodes in carbon limited lithium batteries in plate and jellyroll configurations with the BCX (bromine chloride in thionyl chloride) catholyte gave a specific capacity (at 2 V cut-off) of up to 8700 mAh/g carbon, compared to a value of up to 2900 mAh/g carbon for carbon black. The high specific capacity per g carbon (demonstrating superior carbon efficiency) for the filament electrode is partly due to the filaments' processability into sheets as thin as 0.2 mm with good porosity and without a binder, and partly due to the high catholyte absorptivity and high rate of catholyte absorption of the filament electrode.