Invited Presentation: The Aprotic Lithium-Air Battery

Li-ion and related battery technologies will be important for years to come. However, society needs energy storage that exceeds the capacity of Li-ion batteries. We must explore alternatives to Li-ion if we are to have any hope of meeting the long-term needs for energy storage. One such alternative is the Li-air(O₂) battery; its theoretical specific energy exceeds that of Li-ion, but many hurdles face its realization.^[1-5] First, we must understand the processes that occur in the cell on discharge and charge, then use such knowledge to address the hurdles.

A typical aprotic Li-O₂ battery, shown in Figure 1, consists of a Li anode and a porous cathode, the two being separated by an organic electrolyte. On discharge, O₂ from the atmosphere enters the porous cathode where it is reduced and is supposed to form Li₂O₂, which can be then be oxidised on charging.^[1-5] Charge is stored in the cathode by reversible Li₂O₂ formation/decomposition. However, it is now understood that the reactive nature of reduced O₂ species results in decomposition of many electrolytes and the cathode.^[6-8]

Recent results on electrolyte and cathode stability will be discussed, with a particular focus on the instability of the ubiquitous carbon cathode.^[9-10] By understanding these instabilities, it has been possible to demonstration that when using TiC as the positive electrode, sustained reversible Li₂O₂ formation/decomposition can be achieved, essential if the Li-O₂ battery is ever to succeed.^[11]

References

[1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J.-M. Tarascon, Nat. Mater. 11 (2012) 19-29.

[2] J. Christensen, et al J. Electrochem. Soc. 159 (2012) R1-R30.

[3] G. Girishkumar, B. D. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 1 (2010) 2193-2203.

[4] F. Li, T. Zhang and H. Zhou, Energy Environ. Sci., 2013, 6, 1125-1141.

[5] Y.-C. Lu, B. M. Gallant, D. G. Kwabi, J. R. Harding, R. R. Mitchell, M. S. Whittingham and Y. Shao-Horn, Energy Environ. Sci., 2013, 6, 750-768.

[6] F. Mizuno, S. Nakanishi, Y. Kotani, S. Yokoishi, H. Iba, Electrochemistry 78 (2010) 403-405.

[7] S. H. Oh, R. Black, E. Pomerantseva, J.-H. Lee, L. F. Nazar, Nat. Chem. 4 (2012) 1004-1010.

[8] V. S. Bryantsev, J. Uddin, V. Giordani, W. Walker, D. Addison and G. V. Chase, J. Electrochem. Soc., 2013, 160, A160-A171.

[9] B. D. McCloskey, A. Speidel, R. Scheffler, D. C. Miller, V. Viswanathan, J. S. Hummelshoj, J. K. Norskov, A. C. Luntz, J. Phys. Chem. Lett. 3 (2012) 997-1001.

[10] M. M. Ottakam Thotiyl, S. A. Freunberger, Z. Peng and P. G. Bruce, J. Am. Chem. Soc., 2012, 135, 494-500.

[11] M. M. Ottakam Thotiyl, S. A. Freunberger, Z. Peng, Y. Chen, Y. Liu and P. G. Bruce, Nat. Mater., 2013, 12, 1050-1056.