Local Structures and Li Ion Dynamics in a Li10SnP2S12\mathrm{Li_{10}SnP_{2}S_{12}} -Based Composite Observed by Multinuclear Solid-State NMR Spectroscopy

Multinuclear solid-state nuclear magnetic resonance spectroscopy was used in combination with Mössbauer spectroscopy and synchrotron diffraction to investigate the local and long-range structure as well as the Li-ion dynamics in a Li$_{10}$SnP$_{2}$S$_{12}$-based composite. Although two additional phases could be detected (Li$_{7}$PS$_{6}$ and Li$_{4}$SnS$_{4}$), the Li ion dynamics turn out to be very fast with a Li diffusion coefficient of 1.6 × 10$^{–12}$ m$^{2}$/s, a Li$^{+}$ ion conductivity of ∼2 mS/cm (both at 303 K), and a small activation barrier of 0.13 eV for single Li$^{+}$ ion jumps

Amorphous versus Crystalline Li3PS4Li_3PS_{4}: Local Structural Changes during Synthesis and Li Ion Mobility

Glass–ceramic solid electrolytes have been reported to exhibit high ionic conductivities. Their synthesis can be performed by crystallization of mechanically milled Li2S–P2S5 glasses. Herein, the amorphization process of Li$_2$S–P$_2$S$_5$ (75:25) induced by ball milling was analyzed via X-ray diffraction (XRD), Raman spectroscopy, and $^{31}$P magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. Several structural building blocks such as [P$_4$S$_{10}$], [P$_2$S$_6$]$^{4–}$, [P2S7]$^{4–}$, and [PS$_4$]$^{3–}$ occur during this amorphization process. In addition, high-temperature XRD was used to study the crystallization process of the mechanically milled Li$_2$S–P$_2$S$_5$ glass. Crystallization of phase-pure β-Li$_3$PS$_4$ was observed at temperatures up to 548 K. The kinetics of crystallization was analyzed by integration of the intensity of the Bragg reflections. $^7$Li NMR relaxometry and pulsed field-gradient (PFG) NMR were used to investigate the short-range and long-range Li$^+$ dynamics in these amorphous and crystalline materials. From the diffusion coefficients obtained by PFG NMR, similar Li$^+$ conductivities for the glassy and heat-treated samples were calculated. For the glassy sample and the glass–ceramic β-Li$_3$PS$_4$ (calcination at 523 K for 1 h), a Li$^+$ bulk conductivity σLi of 1.6 × 10$^{–4}$ S/cm (298 K) was obtained, showing that for this system a well-crystalline material is not essential to achieve fast Li-ion dynamics. Impedance measurements reveal a higher overall conductivity for the amorphous sample, suggesting that the influence of grain boundaries is small in this case

Local Structures and Li Ion Dynamics in a Li 10

Multinuclear solid-state nuclear magnetic resonance spectroscopy was used in combination with Mössbauer spectroscopy and synchrotron diffraction to investigate the local and long-range structure as well as the Li-ion dynamics in a Li$_{10}$SnP$_{2}$S$_{12}$-based composite. Although two additional phases could be detected (Li$_{7}$PS$_{6}$ and Li$_{4}$SnS$_{4}$), the Li ion dynamics turn out to be very fast with a Li diffusion coefficient of 1.6 × 10$^{–12}$ m$^{2}$/s, a Li$^{+}$ ion conductivity of ∼2 mS/cm (both at 303 K), and a small activation barrier of 0.13 eV for single Li$^{+}$ ion jumps

Li+\mathrm{Li^{+}} -Ion Dynamics in β−Li3PS4\mathrm{\beta-Li_{3}PS_{4}} Observed by NMR: Local Hopping and Long-Range Transport

A detailed structural characterization is performed on $\mathrm{\beta-Li_{3}PS_{4}}$ using $^6$Li and $^{31}$P magic-angle spinning NMR spectroscopy in combination with X-ray and neutron diffraction. High-temperature synchrotron X-ray diffraction was used to determine the phase stability and observe phase transitions. In addition, we investigated the Li$^+$-ion dynamics by temperature-dependent $^7$Li NMR lineshape analysis, $^7$Li NMR relaxometry, and 7Li pulsed field-gradient (PFG) NMR measurements. A good agreement is obtained between the local hopping observed by T1 relaxation time measurements and the long-range transport investigated by PFG NMR with a Li$^+$ diffusion coefficient of 9 × 10$^{−14}$ m$^2$s at 298 K and an activation energy of 0.24 eV. From this, a Li$^+$ conductivity of 1.0 × 10$^{−4}$ S/cm is estimated, which corresponds well with impedance measurements on$\mathrm{\beta-Li_{3}PS_{4}}$ pellets