Insights into the reaction mechanism of lithium-oxygen batteries could lead to better batteries.
For the lithium-oxygen battery system, it is well recognized the charging and discharging reaction produces peculiar reaction product shapes that resemble doughnuts and balloons. Yet, how these shapes form has remained a mystery. A new study of a functioning nano-lithium-oxygen battery at atomic scale in an oxygen atmosphere provides clues.
The discovery of the lithium-oxygen reaction pathway sets the foundation for quantitative modeling of electrochemical processes in the lithium-oxygen system, providing insight into how best to design lithium-oxygen batteries with high capacity and longer cycle life.
The lithium-oxygen battery system has been perceived as an enabling technology for the electromotive industry. However, progress in research and development of a lithium-oxygen battery has been severely hampered by two unanswered questions. First, what is the electrochemical reaction route when discharging and charging the battery? Second, what is the relationship between the complicated shapes of the reaction product and the reaction path? Answers to these two questions are fundamental, yet essential for development of the lithium-oxygen batteries.
To address this knowledge gap, a team of researchers from Pacific Northwest National Laboratory; Tianjin Polytechnic University of China; and the Environmental Molecular Sciences Laboratory (EMSL), used advanced in-situ imaging techniques—the environmental transmission electron microscope—at EMSL, a Department of Energy Office of Science user facility, to observe a nano-lithium-oxygen battery during charging and discharging. They found oxygen reacts with lithium on carbon nanotubes to form a metastable lithium oxide. This oxide transforms into a more stable lithium oxide and releases oxygen gas that expands (inflates) particles into a hollow structure, producing doughnut and balloon shapes. This observation more generally demonstrates that the way the released oxygen is accommodated governs the formation of the complicated morphology of the reaction product in a lithium-oxygen battery. The results of this work not only answer the two questions outlined above, but also provide insight into ion and electron transport coupled with mass flow for the lithium-oxygen battery.
BER PM Contact
Paul Bayer, SC-23.1, 301-903-5324
Environmental Molecular Sciences Laboratory
This work was supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, and the Environmental Molecular Sciences Laboratory (EMSL), a DOE Office of Science User Facility.
Langli Luo, Bin Liu, Shidong Song, Wu Xu, Ji-Guang Zhang and Chongmin Wang, “Revealing the reaction mechanisms of Li-O2 batteries using environmental transmission electron microscopy.” Nature Nanotechnology (2017). DOI: 10.1038/NNANO.2017.27 (Reference link)
EMSL News How Balloon-shaped Lithium Oxide Reaction Products Form
SC-23.1 Climate and Environmental Sciences Division, BER
BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER
Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]
Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]
Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]
Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]
Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]
List all highlights (possible long download time)