Speaker
Description
As the energy production becomes less of a bottleneck, its storage is still not fully understood. For example the changes occurring at the molecular level are challenging to grasp by integral techniques of pure electrochemistry, therefore the use of operando spectroelectrochemistry becomes an asset.
Raman spectroelectrochemistry for example provides information about changes in the vibrational structure of the molecules at and in some cases (tip enhanced Raman spectroscopy) below the diffraction limit. As many materials used in e.g. Li-ion batteries (LIB) are challenging in spectroscopic investigations due to the small Raman cross-section, surface enhanced spectroscopy is a tool to overcome this obstacle. We present a methodology towards investigation of mechanisms underlying the energy storage in LIB.
A precise coupling of Potentio-Electrochemical-Impedance-Spectroscopy (PEIS) with Surface-Enhanced-Raman-Spectroscopy (SERS) allows for distinguishing between the movements of specific ions in delithiation processes and indicates a surprising fact of e.g. carbon being involved in the overall mechanism. The charge transfer mechanisms and mass-transport properties (intercalationof lithium) can be monitored in time and the kinetics of each reaction/movement investigated in-time (Fig. 1). Raman shifts were found to follow the applied potential and the skin-depth resolved investigation in transition state metallic states of RedOx reactions was made possible. We also present the perspective results about the coupling of Raman Spectroelectrochemistry to Operando X-Ray-Photoelectron-Spectroscopy (XPS) for direct insights into changes of both vibrational and electronic structure during the battery's operation.
References:
M. Radtke, C. Hess Operando Raman shift replaces current in Butler-Volmer analysis of Li-ion batteries: a comparative study (submitted)
M. Radtke, C Hess Surface Enhanced Raman Spectroscopy Substrates for Use in Operando Raman Spectroelectrochemistry (in preparation)
| Speaker Country | Germany |
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