Neutron reflectometry to measure in situ the rate determining step of lithium ion transport through thin silicon layers and interfaces

Abstract

In situ neutron reflectometry experiments found that the interface between silicon and lithium niobate is no significant obstacle for Li permeation.

Electrochemical investigation of ion-beam sputter-deposited carbon thin films for Li-ion batteries

“…In the case of the 16 nm-thin carbon film, the Li permeability is probably high enough to transport all incoming Li into the film interior, whereas for the thicker carbon film, the Li permeability is lower and only the surface near region is lithiated. This may indicate a higher Li permeability of carbon material in thinner films, as it was measured for amorphous silicon material in thin layers [49,50].…”

Analysis of the Diffusion in a Multilayer Structure under a Constant Heating Rate: The Calculation of Activation Energy from the In Situ Neutron Reflectometry Measurement

“…Diffusion coefficients and activation energies for self-diffusion have been obtained with NR − in a variety of materials. In nonoxide high-temperature superhard ceramic coatings, nitrogen self-diffusion was measured in amorphous Si 3 N 4 , and in silicon carbo-nitrides. , For crystalline metal oxides, lithium self-diffusion was examined in LiNbO 3 . , Self-diffusion was measured in metals such as in nanocrystalline copper, iron, , and Fe-based compounds .…”

“…The most common technique is the tracer method, − which tracks the spatial distribution of isotopic elements at different times under the isothermal condition with different techniques, including secondary ion mass spectrometry (SIMS). − Using nuclear magnetic resonance (NMR) − or quasi-elastic neutron scattering (QENS) − makes it possible to analyze atomic diffusion in crystalline materials and in battery research. Diffusion coefficients of atomic diffusion have also been measured by low-angle X-ray diffraction (XRD) (X-ray reflectometry, XRR) in solids, , XRD, , energy-dispersive X-ray spectroscopy, ,, and low-angle neutron diffraction (neutron reflectometry, NR). − Most studies reported in the literature have been based on the isothermal condition, which require multiple measurements at different temperatures in order to determine the activation energy for atomic diffusion in solids. For example, Mizoguchi and Murata conducted low-angle XRD (XRR) analysis of compositionally modulated amorphous Co–Zr films isothermally annealed consecutively at different temperatures in a range of 120–180 °C and calculated the activation energy for the interdiffusion in the modulated amorphous Co–Zr films from the variation of the intensity of the X-ray peak.…”

“…In semiconductors, self-diffusion was measured in crystalline silicon , and germanium and in amorphous silicon and germanium . Extrinsic diffusion (so-called “Fremddiffusion”) was also suitably measured with NR − for lithium permeation through amorphous silicon, − amorphous lithium silicide, and nanocrystalline chromium thin layers. The diffusivities determined by NR were found to be in agreement with the corresponding ones determined from other established techniques such as SIMS. ,,,, The diffusivities and the activation energies for atomic diffusion were generally measured under isothermal-diffusion annealing conditions.…”

“…Extrinsic diffusion (so-called “Fremddiffusion”) was also suitably measured with NR − for lithium permeation through amorphous silicon, − amorphous lithium silicide, and nanocrystalline chromium thin layers. The diffusivities determined by NR were found to be in agreement with the corresponding ones determined from other established techniques such as SIMS. ,,,, The diffusivities and the activation energies for atomic diffusion were generally measured under isothermal-diffusion annealing conditions. The multi-isothermal annealing for the determination of the activation energy of atomic motion is time-consuming and can last more than several hours …”