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

今天，锂离子电池的生产是一项成熟的技术，无论是在比能量密度还是在成本方面都接近进一步提高的极限。金属-空气，特别是锂-空气系统可以成为一种有前途的替代品。从理论上讲，它们提供了尽可能高的比能量密度，因为使用了最轻的金属和来自环境空气的可自由获得的氧化剂。遗憾的是，在实验中，能量密度约为1000Wh/kg的期望值从未接近过。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操作相关的基本问题，特别是在正极方面，为提高锂空气电池的性能做出贡献。在理论多尺度方法中，我们将把电极/溶液界面的结构与含Li+介质中氧还原反应的性质联系起来，并找到有利于放电产物的溶液相生长的条件，从而导致更高的电池容量。将讨论溶液组成以及电极表面结构的影响。我们的项目是基于这样的工作假设，即用化学上不活跃的阳离子取代电极表面附近的锂离子会抑制钝化过程。将测试几个电极表面对缔合和歧化反应步骤的催化性能。从原子尺度的界面模拟得到的结论将使用实验技术进行验证。

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.