Electro-chemical cells requires materials that simultaneously electrically-conduct and allow chemical reactions, activities that conflict with one another. The proposed solution includes a doping gradient strategy such that the dopant materials are appropriate for the function of each region. In the bulk, the material will include a higher concentration of dopants that enhance electron conductivity. At the surface, the material will have a lower concentration of these dopants since they inhibit chemical activity. The advantage is the simultaneous efficiency in both conductivity and reactivity.