Recently, there has been much interest in rechargeable aprotic lithium-oxygen (Li-O2) batteries due to the potential for its gravimetric energy density to be significantly higher than that of the conventional Li-ion batteries. However, many challenges remain for Li-O2 batteries including large  charge overpotentials, electrolyte stability, and poor cycle life. Understanding the properties of interfaces of the discharge product with the cathode as well as the electrolyte is important to addressing these challenges. In this paper we report on density functional calculations on processes occurring at the interface of the discharge product and cathode as well as the electrolytes. In these calculations we use clusters of lithium peroxide and superoxide molecules of up to 16 molecules to model the discharge product surface. These cluster models are used to study lithium superoxide and peroxide interfaces with carbon surfaces interactions and discuss how these interfaces may affect charge processes as well as growth mechanisms occurring on the surfaces. We also present results on interaction of electrolytes with lithium peroxide and superoxide surfaces and relationship to electrolyte stability. The results are compared to experimental studies of the Li-O2 batteries.

Electronic structure of interfaces and their role in charge and discharge chemistries in lithium-oxygen batteries

248th National Meeting (2014)

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