Cell and batteries containing them employing a cathode having a intercalating metal oxide in combination with a sodium metal haloaluminate. At operating temperatures, the positive electrode (cathode) of the invention comprises electroactive cathode material permeated with and in physical and electrical contact with the sodium metal haloaluminate catholyte. The positive and negative electrodes are separated with a solid alkali metal conducting electrolyte. The intercalating metal oxice is not in direct physical contact with the solid electrolyte. Electric and ionic conductivity between the solid electrolyte and the positive electrode is mediated by the sodium haloaluminate catholyte. Batteries of the invention are useful for bulk energy storage, particularly for electric utility grid storage, as well as for electric vehicle propulsion.