In-Situ Liquid EC-(S)TEM Study of Li2O2 growth Mechanism and Morphology in Li-O2 Battery
Currently, Li-O2 batteries are being considered for application in the next generation electric vehicles [1-3], due to their high theoretical energy densities, which are comparable to gasoline . The operation of Li-O2 battery is based on the reversible mechanisms of formation/oxidation of lithium peroxide (Li2O2) at the carbon-based cathode, which ultimately determines battery performance. However, the high capacity values are limited to only few full charge-discharge cycles due to the decomposition of both electrolyte and electrode material during oxygen reduction and evolution. These degradation leads to accumulation of insulating side products, which causes high overpotential and fast capacity fading during cycling.
Here, we employed the in-situ liquid electrochemical (S)TEM cell to create rechargeable Li-O2 “nano-battery” cell. By using the “closed-cell” approached both Li metal-anode and carbon-based cathode submersed in high vapor pressure organic electrolyte (1 M LiTf in tetraglyme). These enabled direct observation of Li2O2 nanoparticles formation at the SWNTs/electrolyte interface at both high spatial and temporal resolution during battery operation.
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The research described in this presentation is part of the Chemical Imaging Initiative at Pacific Northwest National Laboratory under Contract DE-AC05-76RL01830 operated for DOE by Battelle. This work is supported in part by the United States Department of Energy, Basic Energy Sciences Grant No. DE-FG02-03ER46057. A portion of the research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.