Reversibility of anodic lithium in rechargeable lithium-oxygen batteries.
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.
Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Jiang-Lan
JL
Shui
John S
JS
Okasinski
Peter
P
Kenesei
Howard A
HA
Dobbs
Dan
D
Zhao
Jonathan D
JD
Almer
Di-Jia
DJ
Liu