Relation of short-range and long-range lithium ion dynamics in glass-ceramics: Insights from<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Li</mml:mi><mml:mprescripts /><mml:none /><mml:mn>7</mml:mn></mml:mmultiscripts></mml:math>NMR field-cycling and field-gradient studies

Haaks, Michael; Martin, Steve W.; Vogel, Michael

doi:10.1103/physrevb.96.104301

Cited by 27 publications

(22 citation statements)

References 33 publications

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“…The pulse length was between 0.35 and 0.60 μs depending on temperature. The 7 Li SFG measurements were carried out with a setup described in previous work on solid electrolytes . The Larmor frequency was ω 7 Li = 2π·63 MHz, and the corresponding gradient was 73 T/m.…”

Section: Methodsmentioning

confidence: 99%

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From Local to Diffusive Dynamics in Polymer Electrolytes: NMR Studies on Coupling of Polymer and Ion Dynamics across Length and Time Scales

et al. 2019

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We combine 1 H, 7 Li, and 19 F NMR methods to selectively investigate polymer, cation, and anion dynamics in polymer electrolytes on various length and time scales and over broad temperature ranges. By mixing unentangled poly(propylene glycol) (PPG) with lithium perchlorate (LiClO 4 ) or lithium bis-(trifluoromethylsulfonyl)imide (LiTFSI), fully disordered samples are obtained at all studied concentrations. In static field gradient diffusometry, we observe that the longrange motion of all components slows down when the salt concentration is increased, but the effect is more prominent for PPG−LiClO 4 than PPG−LiTFSI electrolytes and, in general, differs for the respective components. The self-diffusion coefficients D of polymer and ions have essentially temperature-independent ratios, where cations are less mobile than anions and do not show Arrhenius temperature dependence. To ascertain short-range motions in broad dynamic ranges, spin−lattice relaxation studies, including field-cycling relaxometry, are combined with stimulated-echo experiments. We show that rate and heterogeneity of local lithium and polymer dynamics depend on the salt content. For intermediate salt concentrations, the segmental motion even exhibits bimodal distributions of correlation times τ, implying structures with salt-rich and salt-depleted regions. Relating diffusion coefficients D and correlation times τ, we find that the lithium ion transport is strongly coupled to polymer segmental motion even in polymer electrolytes with micro-heterogeneous salt distributions. Finally, field-cycling susceptibilities reveal that Rouse dynamics is important not only for the reorganization of polymer chains but also for the transport of lithium ions.

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Section: Methodsmentioning

confidence: 99%

“…The detection fields amounted to 42 and 28 MHz in the former and latter cases, respectively. The temperature was controlled with a flow cryostat for gaseous nitrogen and stabilized on ±0.2 K with a total accuracy of 1 K. Further experimental details of our 1 H and 7 Li FC approaches can be found in previous works. ,− …”

Section: Methodsmentioning

confidence: 99%

From Local to Diffusive Dynamics in Polymer Electrolytes: NMR Studies on Coupling of Polymer and Ion Dynamics across Length and Time Scales

et al. 2019

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“…Obviously, taking the full spin dynamics in such electrolytes into account becomes a challenge . Finally, we mention that 7 Li FC NMR relaxometry combined with solid‐state NMR techniques such as line shape and stimulated echo analysis is a powerful approach to unravel Li ion dynamics in solid‐state electrolytes or glass ceramics, for example …”

Section: Applicationsmentioning

confidence: 99%

“…Most of the FC studies employ 1 H NMR, although other nuclei such as 2 H, 7 Li, or 19 F are suitable, too . Polarization and detection fields higher than 1 Tesla are still difficult to put into practice, therefore, the technique faces relatively low NMR signals in FC relaxometry.…”

Section: Introductionmentioning

confidence: 99%

Application of proton field‐cyclingNMRrelaxometry for studying translational diffusion in simple liquids and polymer melts

Flämig

Hofmann

Lichtinger

et al. 2019

Magnetic Reson in Chemistry

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“…The issue of low signals inherent to low-field NMR is overcome by rapidly cycling through polarization–relaxation–acquisition intervals . Although other nuclei are possible, − the majority of FC NMR studies addresses the relaxation of the abundant proton ( 1 H), for which spin–lattice relaxation is primarily caused by fluctuations of dipole–dipole couplings, and for which Larmor frequencies on the order of tens of megahertz down to several tens of Hertz result. Recently, a low field record of 3 Hz could be achieved…”

Section: Introductionmentioning

confidence: 99%

Mode Analysis of NMR Relaxation in a Polymer Melt

Hofmann

2018

Macromolecules

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Spin−lattice relaxation rates of unentangled poly-(dimethylsiloxane) (PDMS) melts of different M measured by field-cycling (FC) 1 H NMR are analyzed using a new approach. By fitting the time domain mode distribution of the Rouse model to the experimental data, interpolation of the latter is achieved and a mode separation is performed. The evolution of the Rouse relaxation spectrum with increasing M is studied. From the model parameters, the diffusion coefficient D, the Rouse time τ R , and the statistical length are calculated, all in good agreement with literature values and the Rouse model. The new approach allows for a more accurate calculation of the segmental mean square displacement, removes previous discrepancies between FC and field-gradient NMR and verifies the relevant relaxation theory. Furthermore, for the first time, the analysis provides the radius of gyration R G , the values of which are in agreement with literature values obtained by small-angle neutron scattering. The Mdependence R G ∝ M 0.53±0.04 indicates ideal chain statistics down to M = 860 g/mol.

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Relation of short-range and long-range lithium ion dynamics in glass-ceramics: Insights fromLi7NMR field-cycling and field-gradient studies

Cited by 27 publications

References 33 publications

From Local to Diffusive Dynamics in Polymer Electrolytes: NMR Studies on Coupling of Polymer and Ion Dynamics across Length and Time Scales

From Local to Diffusive Dynamics in Polymer Electrolytes: NMR Studies on Coupling of Polymer and Ion Dynamics across Length and Time Scales

Application of proton field‐cyclingNMRrelaxometry for studying translational diffusion in simple liquids and polymer melts

Mode Analysis of NMR Relaxation in a Polymer Melt

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