The Aprotic Lithium-Air Battery: New Insights into Materials and Reactions
The discharge reaction in the cathode of the nonaqueous Li-O2 cell involves reduction of O2 and the formation of solid Li2O2; the process is reversed on charge, O2 + 2 Li+ + 2 e– « Li2O2. It is now understood that parasitic reactions are a major cause for overpotentials on discharge and charge and limited cycle life. These are both caused by decomposition of many electrolytes and the cathode. Poor electron transport in Li2O2 is recognized as a major factor limiting its achievable amount during discharge (that is, achievable capacity) and the rate and overpotentials at which it can be formed and decomposed during cycling[4-6]. A further major challenge is extended cyclability at desirable deep discharge. We will discuss recent insights into the mechanism of Li2O2 formation and decomposition, of parasitic reactions and novel electrode and electrolyte materials.
 P.G. Bruce, S.A. Freunberger, L.J. Hardwick, J.-M. Tarascon, Nature Mater. 11 (2012) 19.
 J. Christensen, P. Albertus, R.S. Sanchez-Carrera et al., J. Electrochem. Soc. 159 (2012) R1.
 Y.-C. Lu, B.M. Gallant, D.G. Kwabi et al., Energy Environ. Sci. 6 (2013) 750.
 Y. Chen, S.A. Freunberger, Z. Peng, O. Fontaine, P.G. Bruce, Nature Chem. 5 (2013) 489.
 A. Dunst, V. Epp, I. Hanzu, S.A. Freunberger, M. Wilkening, Energy Environ. Sci. 7 (2014) 2739.
 L. Johnson, C. Li, Z. Liu et al., Nature Chem. 6 (2014) 1091