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Magic‐angle‐spinning (MAS) enhances sensitivity and resolution in solid‐state nuclear magnetic resonance (NMR) measurements. MAS is obtained by aerodynamic levitation and drive of a rotor, which results in large centrifugal forces that may affect the physical state of soft materials, such as polymers, and subsequent solid‐state NMR measurements. Here, we investigate the effects of MAS on the solid‐state NMR measurements of a polymer electrolyte for lithium‐ion battery applications, poly(ethylene oxide) (PEO) doped with the lithium salt LiTFSI. We show that MAS induces local chain ordering, which manifests itself as characteristic lineshapes with doublet‐like splittings in subsequent solid‐state 1H, 7Li, and 19F static NMR spectra characterizing the PEO chains and solvated ions. MAS results in distributions of stresses and hence local chain orientations within the rotor, yielding distributions in the local magnetic susceptibility tensor that give rise to the observed NMR anisotropy and lineshapes. The effects of MAS were investigated on solid‐state 7Li and 19F pulsed‐field‐gradient (PFG) diffusion and 7Li longitudinal relaxation NMR measurements. Activation energies for ion diffusion were affected modestly by MAS. 7Li longitudinal relaxation rates, which are sensitive to lithium‐ion dynamics in the nanosecond regime, were essentially unchanged by MAS. We recommend that NMR researchers studying soft polymeric materials use only the spin rates necessary to achieve the desired enhancements in sensitivity and resolution, as well as acquire static NMR spectra after MAS experiments to reveal any signs of stress‐induced local ordering. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are electrochemical storage devices using the electrochemical activity of the lithium ion in relation to intercalation compounds owing to mass transport phenomena through diffusion. Diffusion of the lithium ion in the electrode pores has been poorly understood due to the lack of experimental techniques for measuring its self-diffusion coefficient in porous media. Magic-Angle Spinning, Pulsed Field Gradient, Stimulated-Echo Nuclear Magnetic Resonance (MAS-PFG-STE NMR) was used here for the first time to measure the self-diffusion coefficients of the electrolyte species in the LP30 battery electrolyte (i.e. a 1 M solution of LiPF 6 dissolved in 1:1 Ethylene Carbonate - Dimethyl Carbonate) in model composites. These composite electrodes were made of alumina, carbon black and PVdF-HFP. Alumina's magnetic susceptibility is close to the measured magnetic susceptibility of the LP30 electrolyte thereby limiting undesirable internal field gradients. Interestingly, the self-diffusion coefficient of lithium ions decreases with increasing carbon content. FIB-SEM was used to describe the 3D geometry of the samples. The comparison between the reduction of self-diffusion coefficients as measured by PFG-NMR and as geometrically derived from FIB/SEM tortuosity values highlights the contribution of specific interactions at the material/electrolyte interface on the lithium transport properties. [ABSTRACT FROM AUTHOR]

The glassy ternary system Ge-Te-Se is currently receiving an increased attention due to its extended range of transmission in the infrared opening the way to various potential applications in photonics. In this study, a multi-techniques approach combining solid-state NMR, Raman and infrared spectroscopies and DFT calculations provides insight into the organization of the GeSe 4 -GeTe 4 glassy network and allows to clarify a whole structural description of the glassy system. A particular attention is devoted to the presence of mixed GeTe 8-x Se x structural units and to the type of interconnections forming the glass networks. Such experimental/theoretical approach is provided both for the selenium and the tellurium rich part of the glassy system. A multi technical approach (Raman, IR, NMR and DFT calculation) to describe mixed selenide-telluride glassy structures. [Display omitted] • A multi technical approach (Raman, IR, NMR and DFT calculation) to describe mixed selenide-telluride glassy structures. • Structural description for both the selenide and telluride rich part the system. • Local structural entities and their interconnections description in this GeSeTe glassy structures. [ABSTRACT FROM AUTHOR]