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

今天，锂离子电池生产是一项成熟的技术，在比能量密度和成本方面都接近进一步改进的极限。金属-空气，特别是锂-空气系统可能成为一个有前途的替代品。从理论上讲，它们提供了最高可能的比能量密度，因为使用了最轻的金属和环境空气中可自由获得的氧化剂。不幸的是，在实验中甚至从未接近约1000 Wh/kg的能量密度的预期值。在这个德俄联合研究项目中，我们的目标是通过研究与锂空气电池运行相关的基本问题，特别是在阴极，为提高锂空气电池的性能做出贡献。在一个理论的多尺度方法，我们将涉及的电极/溶液界面的结构的氧还原反应在含锂的介质中的属性，并找到有利于放电产物的溶液相生长，从而导致更高的电池容量的条件。溶液的组成以及电极表面的结构的影响将得到解决。我们的项目是基于工作假设，即用化学惰性阳离子取代电极表面附近的Li阳离子抑制钝化过程。将测试几种电极表面对缔合和反离子化反应步骤的催化性能。将使用实验技术验证从原子尺度模拟的接口所得到的结论。

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.