Abstract: In a sodium-sulphur cell, liquid sodium is anodic reactant, sulphur and sodium polysulphide are cathodic reactants and sodium ions are conducted by a solid electrolyte. To increase cell capacity and improve safety, a storage region for cathodic reactants is provided away from said solid electrolyte and containing said cathodic reactants in the form of two contacting layers of immiscible liquids formed by gravitational separation. Liquid sulphur being stored does not contact the solid electrolyte. The sodium may also be stored out of contact with the electrolyte. Capillary-action means for feeding the sodium polysulphide from the two liquid layers to the cathode reaction, and for feeding sodium to the anode reaction are included.