Lithium Diffusion in Ion-Beam Sputter-Deposited Lithium-Silicon Layers
Lithium Diffusion in Ion-Beam Sputter-Deposited Lithium-Silicon Layers
Strauss, F.; Hüger, E.; Julin, J. A.; Munnik, F.; Schmidt, H.
Lithium-silicon compounds are used as active material in negative electrodes of Li-ion batteries. The knowledge of Li diffusion in these materials is of importance for an optimization of charging/discharging rates and achievable maximum specific capacity as well as for an understanding of the basic lithiation mechanism. We carried out Li tracer self-diffusion experiments on ion-beam sputter-deposited LixSi(O) thin films for x ~ 0.25 and x ~ 4.5 using LixSi/6LixSi hetero-structures in combination with secondary ion mass spectrometry in line scan like mode. Measurements with elastic recoil detection analysis revealed the presence of a considerable amount of oxygen in the films. The diffusivities follow the Arrhenius law in the temperature range between 300 and 500 °C with an activation energy of 0.8 – 0.9 eV. The film containing a higher amount of Li shows faster diffusion by one order of magnitude. The Li diffusivities in the investigated Li-rich materials are several orders of magnitude higher than in Li-poor LixSi films (x = 0.02 to 0.06) as given in literature because of a lower activation energy. This indicates the presence of a direct interstitial-like mechanism. Oxygen present in samples with the same Li concentration of x = 0.06 also enhances diffusion but does not lead to a reduction in the activation energy.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
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- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30875) publication
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Journal of Physical Chemistry C 124(2020), 8616-8623
DOI: 10.1021/acs.jpcc.0c01244
Cited 9 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30875