A conductive, elastic, electroactive binder composed of polypyrrole and polyurethane is adopted for flexible, high-loading lithium-sulfur cathodes. The conductivity of the polypyrrole helps mitigate the negative effects of insulating sulfur, and the elastomeric matrix accommodates sulfur volume expansion. The binder is used with a simple carbon/sulfur composite to produce high-performance, flexible electrodes without excessive carbon, interlayers, or special additives.