For electric vehicles (EV) having a 500 km range between charges, there is a need to develop smaller and lower-cost batteries. Lithium-air has the potential to deliver a step change in the specific energy of rechargeable lithium batteries. In order to develop a practical, safe, smaller and lower-cost lithium and sodium-air rechargeable EV battery iris necessary to eliminate the formation of dendritic deposits (on charge), increase the current density up to 100 mA cm(-2) (or reducing cell DC resistance to less than 10 Omega cm(2)) and change the oxygen-discharge product from peroxide to oxide. We suggest here a novel concept, namely to replace the metallic lithium anode by liquid sodium and to operate the sodium-oxygen cell above the sodium melting point (97.8 degrees C). In this report we studied the deposition-dissolution process of sodium in polymer electrolytes at 105 degrees C and we present, for the first time, preliminary results that demonstrate the feasibility of running a liquid-sodium-oxygen cell with polymer electrolytes at above 100 degrees C. (C) 2010 Elsevier B.V. All rights reserved.