Although H-2/O-2 fuel cells using Li2SO4 as the electrolyte have encountered problems in their chemical instability, the Li2SO4 electrolyte shows an excellent chemical stability under the operation conditions of a fuel cell using H2S as the fuel. Both thermodynamic analysis and experiments have demonstrated that it is feasible to develope practical H2S/O-2 fuel cells and co-generation devices based on the Li2SO4 electrolyte. (C) 2000 Elsevier Science B.V. All rights reserved.