Mapping Li(+) Concentration and Transport via In Situ Confocal Raman Microscopy.
We demonstrate confocal Raman microscopy as a general, nonperturbative tool to measure spatially resolved lithium ion concentrations in liquid electrolytes. By combining this high-spatial-resolution technique with a simple microfluidic device, we are able to measure the diffusion coefficient of lithium ions in dimethyl carbonate in two different concentration regimes. Because lithium ion transport plays a key role in the function of a variety of electrochemical devices, quantifying and visualizing this process is crucial for understanding device performance. This method for detecting lithium ions should be immediately useful in the study of lithium-ion-based devices, ion transport in porous media, and at electrode-electrolyte interfaces, and the analytical framework is useful for any system exhibiting a concentration-dependent Raman spectrum.
†Molecular Foundry, Materials Sciences Division and §Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Jason D
JD
Forster
†Molecular Foundry, Materials Sciences Division and §Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Stephen J
SJ
Harris
†Molecular Foundry, Materials Sciences Division and §Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Jeffrey J
JJ
Urban
Raman spectroscopy; diffusion; lithium ion transport