The Impact of Li Grain Size on Coulombic Efficiency in Li Batteries
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Florida State Univ., Tallahassee, FL (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pennsylvania State Univ., University Park, PA (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States)
One of the most promising means to increase the energy density of state-of-the-art lithium (Li)-ion batteries is to replace the graphite anode with a Li metal anode1, 2, 3. While the direct use of Li metal may be highly advantageous4,5, at present its practical application is limited by issues related to dendrite growth and low Coulombic efficiency (CE)6. Here operando electrochemical scanning transmission electron microscopy (STEM) is used to directly image the deposition/stripping of Li at the anode-electrolyte interface in a Li-based battery. A non-aqueous electrolyte containing small amounts of H2O as an additive results in remarkably different deposition/stripping properties as compared to the "dry" electrolyte when operated under identical electrochemical conditions. The electrolyte with the additive deposits more Li during the first cycle, with the grain sizes of the Li deposits being significantly larger and more variable. Here, the stripping of the Li upon discharge is also more complete, i.e., there is a higher cycling CE. This suggests that larger grain sizes are indicative of better performance by leading to more uniform Li deposition and an overall decrease in the formation of Li dendrites and side reactions with electrolyte components, thus potentially paving the way for the direct use of Li metal in battery technologies.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1340836
- Report Number(s):
- PNNL-SA-120401; 48681; KC0208010
- Journal Information:
- Scientific Reports, Vol. 6; ISSN 2045-2322
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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