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Silver Nanowires for Li-O2 Batteries

Monday, 20 June 2016
Riverside Center (Hyatt Regency)
W. J. Kwak (Department of Energy Engineering, Hanyang University), H. G. Jung (Korea Institute of Science and Technology), D. Aurbach (Bar-Ilan University), and Y. K. Sun (Hanyang University)
In Li-O2 battery system, precipitation of Li2O2 passivate the cathode’s surface during charging, what terminates electrochemical reaction and limit the cell capacity.1,2 In the charging process, oxidation of the non-conductive Li peroxide precipitants requires high over-potentials, in which solution species may be readily oxidized. In order to address these shortcomings, many researchers3,4 tried to modify the morphology, size, and crystallinity of Li2O2 during its generation by electro-catalysis and the use of composite cathodes comprising nano-materials.

Efforts have been made to decrease the overpotential at the formation and decomposition of Li2O2, by identifying catalysts that can control the morphology of Li2O2. Morphological control makes Li2O2 easier to decompose on oxygen evolution reaction (OER). Herein, we show that silver nanowires as cathode materials for Li–oxygen batteries. AgNW greatly reduce the charging over-potential needed for OER at the solution/electrode interface and are more effective than silver nanoparticles (AgNP). AgNW deliver reversible Li2O2 formation/decomposition on discharge/charge with an average charging potential of ∼3.4 V without electrolyte solution decomposition after 50 cycles. We confirmed that unique Li2O2 structure can promote the decomposition at low charge potential upon oxygen evolution reaction leading to high electrical efficiently of Li-air batteries up to 83.4%.

References

 

(1)     Kraytsberg, A.; Ein-Eli, Y. J. Power Sources 2011, 196, 886–893.

(2)      Viswanathan, V.; Thygesen, K. S.; Hummelshoj, J. S.; Norskov, J. K.; Girishkumar, G.; McCloskey, B. D.; Luntz, A. C. J. Chem. Phys. 2011, 135, 214704 (1–10).

(3)      Mitchell, R. R.; Gallant, B. M.; Shao-Horn, Y.; Thompson, C. V. J. Phys. Chem. Lett. 2013, 4, 1060–1064.

(4)      Adams, B. D.; Radtke, C.; Black, R.; Trudeau, M. L.; Zaghib, K.; Nazar, L. F. Energy Environ. Sci. 2013, 6, 1772–1778.