A novel air electrode design: A key to high rate capability and long life span

As an appealing storage system for electric vehicle application, the lithium-oxygen battery could theoretically provide ultrahigh energy density; however, its attractive implementation is overshadowed by unsatisfactory electrochemical characteristics of the poor rate capability and the short span life. Here, we put forward one kind of effective strategy to ameliorate these deficiencies. By embedding a novel air electrode, the utilization level of the electrochemically available active sites is effectively increased and meanwhile the mass transfer of oxygen is signally improved. The evaporation speed of the solvent is greatly slowed down to some degree. We demonstrate that a super P-based lithium-O-2 battery could be operated over stable 50 cycles at the current density of 3000 mA g(Carbon)(-1) (equivalent to 2.4 mA cm(-2)), corresponding to a discharge time of about 20 min to 1000 mAh g(Carbon)(-1). Based on the weight of the super P and the resultant Li2O2, the specific power density could reach 4040 W kg(-1); even so, a substantial specific energy density of 1350 Wh kg(-1) still could be achieved. (C) 2014 Elsevier B.V. All rights reserved.