An improved carbon cathode and its use in a Li/SO.sub.2 battery wherein the cathode is formed from a microporous sheet having a substantially uniform mixture of from 7 to 22 volume percent of an ultra-high molecular weight polyethylene, from 78 to 93 volume percent of a conductive carbon black and from 0 to 2 volume percent of a plasticizer for the polyethylene. The microporous sheet has a void volume of at least 75 percent and exhibits electrical conductivity of at least 0.05 ohm.sup.-1 cm.sup.-1.