Sulfur cathodes were also prepared by electropolymerisation with electrically conductive substrates such as carbon fibre cloth and fine stainless steel mesh. For electropolymerisation, a solution containing sulfur, carbon black, Nafion, pyrrole monomer and a dopant like sulfate is prepared. Cathodes were readily prepared by applying a potential for a certain period of time while mixing the solution. The loading of sulfur can reach up to 30% based on the amount of sulfur in the starting solution. The prepared cathodes showed high initial discharge capacities of 1500 mAh/g along with a coulombic efficiency of 97%.
The use of such fibrous substrates adds another dimension to sulfur cathode technology by providing more control over the content and nature of active functional groups, surface porosity, and morphology. Each of these factors can be employed to counter the problem of polysulfide shuttling by enhancing the retention of sulfur reduction products within the cathode. In addition substrates which are electrically non-conductive can act both as a cathode and separator at the same time, without the need for an additional physical separator, by simple re-arrangement of the cell’s active components.