scholarly journals Tracking Ions the Direct Way: Long-Range Li+ Dynamics in the Thio-LISICON Family Li4MCh4 (M = Sn, Ge; Ch = S, Se) as Probed by 7Li NMR Relaxometry and 7Li Spin-Alignment Echo NMR

2021 ◽  
Vol 125 (4) ◽  
pp. 2306-2317
Author(s):  
Katharina Hogrefe ◽  
Nicolò Minafra ◽  
Wolfgang G. Zeier ◽  
H. Martin R. Wilkening
Keyword(s):  
Long Range ◽  
Spin Alignment ◽  
Nmr Relaxometry ◽  
7Li Nmr

7Li NMR Studies of Short-Range and Long-Range Lithium Ion Dynamics in a Heat-Treated Lithium Iodide-Doped Lithium Thiophosphate Glass Featuring High Ion Conductivity

2020 ◽  
Vol 124 (52) ◽  
pp. 28614-28622
Author(s):  
Edda Winter ◽  
Philipp Seipel ◽  
Vanessa Miß ◽  
Stefan Spannenberger ◽  
Bernhard Roling ◽  
...  
Keyword(s):  
Long Range ◽  
Short Range ◽  
Lithium Ion ◽  
Ion Conductivity ◽  
Ion Dynamics ◽  
Lithium Iodide ◽  
Nmr Studies ◽  
Heat Treated ◽  
7Li Nmr

scholarly journals Controlled Surface Reconstruction on Ferromagnetic Oxides: Spin Pinning Effect to the Oxyhydroxide Layer and Its Enhanced Oxygen Evolution Activity

2021 ◽  
Author(s):  
Tianze Wu ◽  
Xiao Ren ◽  
Yuanmiao Sun ◽  
Shengnan Sun ◽  
Guoyu Xian ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Long Range ◽  
Spin Polarization ◽  
Water Electrolysis ◽  
Intrinsic Activity ◽  
Spin Alignment ◽  
Pinning Effect ◽  
Production Of Hydrogen ◽  
Ferromagnetic Oxides ◽  
Kinetic Barriers

The production of hydrogen by water electrolysis suffers from the kinetic barriers in the oxygen evolution reaction (OER) that limits the overall efficiency. As spin-dependent kinetics exist in OER, the spin alignment in active OER catalysts is critical for reducing the kinetic barriers in OER. It is effective to facilitate the spin polarization in ferromagnetic catalysts by applying external magnetic field, which increases the OER efficiency. However, more active OER catalysts tend to have dynamic open-shell orbital configurations with disordered magnetic moments, without showing an apparent long-range interatomic ferromagnetism; thus controlling the spin alignment of these active catalysts is challenging. In this work, we report a strategy with spin pinning effect to make the spins in active oxyhydroxides more aligned for higher intrinsic OER activity. Such strategy bases on a controllable reconstruction: ferromagnetic oxides with controlled sulfurization can evolve into stable oxide<sub>FM</sub>/oxyhydroxide configurations with a thin oxyhydroxide layer under operando condition. The spin pinning effect is found at the interface of oxide<sub>FM</sub>/oxyhydroxide. The spin pinning effect can promote spin selective electron transfer on OER intermediates to generate oxygens with parallel spin alignment, which facilitates the production of triplet oxygen and increases the intrinsic activity of oxyhydroxide by ~ 1 order of magnitude. Under spin pinning, the spins in oxyhydroxide can become more aligned after magnetization as long-range ferromagnetic ordering is established on the magnetic domains in oxide<sub>FM</sub>. The OER kinetics are facilitated accordingly after magnetization, implying that the spin pinning effect is involved in the rate-determining step and this step is spin dependent. The spin polarization process in OER under spin pinning is also believed to be sensitive to the existence of active oxygen ligand (O(-)) in oxyhydroxide. When the O(-) is created in 1<sup>st</sup> deprotonation step under high pH, the spin polarization of ligand oxygens will be facilitated, which reduces the barrier for subsequent O-O coupling and promotes the O<sub>2</sub> turnover.

scholarly journals Independent component analysis combined with Laplace inversion of spectrally resolved spin-alignment echo/T1 3D 7Li NMR of superionic Li10GeP2S12

2021 ◽  
Author(s):  
Marc C. Paulus ◽  
Anja Paulus ◽  
Rüdiger-A. Eichel ◽  
Josef Granwehr
Keyword(s):  
Independent Component Analysis ◽  
Component Analysis ◽  
Independent Component ◽  
Inverse Laplace Transform ◽  
Superionic Conductors ◽  
Spin Alignment ◽  
Laplace Inversion ◽  
Independent Components ◽  
7Li Nmr ◽  
Spectrally Resolved

The use of independent component analysis (ICA) for the analysis of two-dimensional (2D) spin-alignment echo--T1 7Li NMR correlation data with transient echo detection as a third dimension is demonstrated for the superionic conductor Li10GeP2S12 (LGPS). ICA was combined with Laplace inversion, or discrete inverse Laplace transform (ILT), to obtain spectrally resolved 2D correlation maps. Robust results were obtained with the spectra as well as the vectorized correlation maps as independent components. It was also shown that the order of ICA and ILT steps can be swapped. While performing the ILT step before ICA provided better contrast, a substantial data compression can be achieved if ICA is executed first. Thereby the overall computation time could be reduced by one to two orders of magnitude, since the number of computationally expensive ILT steps is limited to the number of retained independent components. For LGPS, it was demonstrated that physically meaningful independent components and mixing matrices are obtained, which could be correlated with previously investigated material properties yet provided a clearer, better separation of features in the data. LGPS from two different batches was investigated, which showed substantial differences in their spectral and relaxation behavior. While in both cases this could be attributed to ionic mobility, the presented analysis may also clear the way for a more in-depth theoretical analysis based on numerical simulations. The presented method appears to be particularly suitable for samples with at least partially resolved static quadrupolar spectra, such as alkali metal ions in superionic conductors. The good stability of the ICA analysis makes this a prospect algorithm for preprocessing of data for a subsequent automatized analysis using machine learning concepts.

scholarly journals Correlated fluorine diffusion and ionic conduction in the nanocrystalline F− solid electrolyte Ba0.6La0.4F2.4—19F T1(ρ) NMR relaxation vs. conductivity measurements

2014 ◽  
Vol 16 (20) ◽  
pp. 9580-9590 ◽  
Author(s):  
F. Preishuber-Pflügl ◽  
P. Bottke ◽  
V. Pregartner ◽  
B. Bitschnau ◽  
M. Wilkening
Keyword(s):  
Solid Electrolyte ◽  
Long Range ◽  
Short Range ◽  
Ionic Conduction ◽  
Nmr Relaxation ◽  
Conductivity Measurements ◽  
Nmr Relaxometry ◽  
Migration Pathways

19F NMR relaxometry and conductivity spectroscopy precisely track the defect-mediated short-range and long-range anion migration pathways in nanocrystalline Ba0.6La0.4F2.4.

Through-Bond and Long-Range Ferromagnetic Spin Alignment in a .pi.-Conjugated Polyradical with a Poly(phenylenevinylene) Skeleton

1995 ◽  
Vol 117 (1) ◽  
pp. 548-549 ◽  
Author(s):  
Hiroyuki Nishide ◽  
Takashi Kaneko ◽  
Takeshi Nii ◽  
Kohya Katoh ◽  
Eishun Tsuchida ◽  
...  
Keyword(s):  
Long Range ◽  
Spin Alignment ◽  
Pi Conjugated
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