Enhancing capacity and rechargeability of lithium-air batteries by precise control of reaction zonedimensions and mediators

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Today, lithium-ion batteries production is a mature technology approaching the limit of further improvement in terms of both specificenergy density and cost. Metal-air, and especially lithium-air systems can become a promising replacement. Theoretically, they provide the highest possible specific energy density as the lightest metal and freely available oxidizer from ambient air are used. Unfortunately, the expected value of the energy density of about 1000 Wh/kg has never been even approached in the experiments. In this joint German-Russian research project, our goal is to contribute to improve the performance of Li-air batteries by studying fundamental issues related to Li-air battery operation, in particular at the cathode. In a theoretical multiscale approach, we will relate the structure of the electrode/solution interface to the properties of the oxygen reduction reaction in Li+-containing media and find conditions favorable for solution phase growth of discharge product which leads to higher cell capacity. The influence of both the solution composition and as well as the structure of the electrode surface will be addressed. Our project is based on the working hypothesis that the replacement of Li cations near the electrode surface with chemically inactive cations inhibits the passivation process. Several electrode surfaces will be tested for catalytic properties toward association and disproportionation reaction steps. The conclusions obtained from atomic-scale simulations of the interface will be validated using experimental techniques.