Rechargeable aqueous Na-air batteries: Highly improved voltage efficiency by use of catalysts

The first rechargeable aqueous Na-air battery has been fabricated, and its electrochemical properties and reversibility are reported herein. The charge-discharge properties of the battery were tested using both Vulcan XC72R-and Pt/C-coated carbon paper as the air electrode. Pt/C-coated carbon paper exhibited a voltage efficiency of 84.3%, whereas, for Vulcan XC72R-coated carbon paper and uncoated carbon paper, the observed efficiencies were 78.0% and 72.4%, respectively. Use of Pt/C-coated carbon paper led to a high and stable discharging voltage of 2.85 V. The reported rechargeable aqueous Na-air battery is a potential candidate for high energy density batteries in the future. (C) 2015 Elsevier B.V. All rights reserved.