Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Nat Commun. 2013;4:2255. doi: 10.1038/ncomms3255.
Non-aqueous lithium-air batteries represent the next-generation energy storage devices with very high theoretical capacity. The benefit of lithium-air batteries is based on the assumption that the anodic lithium is completely reversible during the discharge-charge process. Here we report our investigation on the reversibility of the anodic lithium inside of an operating lithium-air battery using spatially and temporally resolved synchrotron X-ray diffraction and three-dimensional micro-tomography technique. A combined electrochemical process is found, consisting of a partial recovery of lithium metal during the charging cycle and a constant accumulation of lithium hydroxide under both charging and discharging conditions. A lithium hydroxide layer forms on the anode separating the lithium metal from the separator. However, numerous microscopic 'tunnels' are also found within the hydroxide layer that provide a pathway to connect the metallic lithium with the electrolyte, enabling sustained ion-transport and battery operation until the total consumption of lithium.
非水锂空电池代表了具有极高理论容量的下一代储能装置。锂空电池的优势基于这样一个假设，即在充放电过程中，阳极锂是完全可逆的。在这里，我们使用空间和时间分辨的同步加速器 X 射线衍射和三维微断层扫描技术，报告了我们对工作中的锂空电池内部阳极锂可逆性的研究。发现了一种组合的电化学过程，包括在充电循环期间部分恢复金属锂，以及在充电和放电条件下锂氢氧化物的不断积累。在阳极上形成了一层氢氧化锂，将金属锂与隔膜隔开。然而，在氢氧化锂层内还发现了许多微观“隧道”，为连接金属锂与电解质提供了途径，从而实现持续的离子传输和电池运行，直到锂完全耗尽。
