Electrochemical Studies of Li(SO2)3AICI4 Electrolytes Containing Added Halogens

Cyclic vo l tammograms at smooth carbon electrodes and galvanostatic discharge/charge cycles of porous carbon elec-trodes were obtained in both pure Li(SO2)3A1C14 and in Li(SO~)3A1C14 containing added halogens. Qualitative differences in cyclic vo l tammograms and discharge/charge curves with electrolyte containing various halogens can be related to differ-ences in halogen reduct ion potentials. Use of the l i th ium/su l fu r d iox ide coup le in recharge-able cel ls has recent ly been act ive ly s tud ied (1-5). One form of this cell consists of a l i th ium anode, a porous car-bon black cathode, and a highly conduct ive, l iquid elec-t ro lyte that is easi ly fo rmed when sol id LiAIC14 reacts with gaseous SO2. At room temperature and atmospher ic pressure, this l iqu id complex has the formula Li(SO2)aA1C14 (5-7) and a measured conduct iv i ty of 0.13 S/cm (5). Dur ing discharge of this cell, SO2 is be l ieved to be reduced to d i th ioni te ions at the cathode, whi le at th