Image courtesy of Argonne National Laboratory
Spectroscopic Fingerprinting – The energy loss from inelastic x-ray scattering (IXS) is sensitive to the bonding and chemical structure of the lithium and oxygen atoms and provides a spectral fingerprint (left) of various possible SEI species that can be validated by theoretically calculated spectra (right).
Spectroscopic fingerprints for a suite of possible degradation products at the solid-electrolyte interface (SEI) of lithium ion batteries were developed using theoretically validated measurements of lithium and oxygen in pure, bulk materials.
Powerful in-situ characterization and identification of degradation products formed inside operating lithium ion batteries will provide insights on how to make batteries better. The technique is now available to the open research community at a DOE user facility.
Understanding what happens inside of rechargeable batteries is critical to making them safer and last longer. For commercially important lithium-based batteries, a new tool has been developed that uses high resolution lithium and oxygen spectroscopy to study the degradation products formed in a working battery. Inelastic x-ray scattering (IXS) measures and analyzes the energy lost by x-rays when they are scattered by light elements such as lithium; the resulting spectrum is very sensitive to the bonding and chemical structure of the atoms in the material being analyzed. Unlike traditional spectroscopic probes, IXS uses high energy x-rays that can penetrate deep inside a working battery – assessing the elemental changes at the critical solid-electrolyte interface(SEI) inside the battery. Work at Argonne National Laboratory supported by the Center for Electrical Energy Storage, a DOE Energy Research Frontier Center, is using lithium and oxygen spectra of pure, known compounds to create a catalogue of spectroscopic fingerprints of the possible decomposition productions in lithium-ion batteries. Theoretical calculations agree with the measured spectra of pure compounds, providing validation that the IXS spectra can be used to probe an unknown mixture of SEI products. Ongoing studies will use the fingerprints to determine the composition of the SEI and to decouple decomposition reactions from actual discharge products for a Li-air battery. This technique is now available to the broader battery research community at Argonne’s Advanced Photon Source.
Tim T. Fister
Argonne National Laboratory
Advanced Photon Source
Director of the Center for Electrical Energy Storage (CEES)
DOE Office of Science, Office of Basic Energy Sciences, Energy Frontier Research Centers (EFRC) Program; Part of the research was performed at DOE Basic Energy Sciences user facilities: Advanced Photon Source (APS) and Center for Nanoscale Materials. The APS beamline has partial support from the Natural Sciences and Engineering Research Council of Canada.
Fister, T.T. Schmidt, Moritz; Johnson, ChristopherS.; Slater, MichaelD.; Shirley, Eric L. ; Chan, MariaK. Y.; and Fenter, Paul “Electronic structures of lithium battery interphase compounds: comparison between inelastic x-ray scattering measurements and theory” J. Chem. Phys., 135, 224513 (2011). [DOI: 10.1063/1.3664620];
Chan, MariaK. Y.; Shirley, Eric L.; Karan, NabaK; Balasubramanian, M.; Greeley, JeffreyP; and Fister, T.T. “Structure of lithium peroxide” J. Phys. Chem. Lett., 2, 2483–2486 (2011). [DOI: 10.1021/jz201072b]
Center for Electrical Energy Storage (CEES) EFRC
Advanced Photon Source (APS)
Center for Nanoscale Materials
DOE Laboratory, SC User Facilities, BES User Facilities, APS, CNM