Ion transport mechanism in anhydrous lithium thiocyanate LiSCN Part I: ionic conductivity and defect chemistry

Abstract

This work reports on the ion transport properties and defect chemistry in anhydrous lithium thiocyanate Li(SCN), which is a pseudo-halide Li+ cation conductor. An extensive doping study was conducted, employing...

Ion transport mechanism in anhydrous lithium thiocyanate LiSCN part II: frequency dependence and slow jump relaxation

“…The newly discovered phase Mg 1.02 Li 3.96 (SCN) 6 in Part I 1 is a perfect comparison to Li(SCN) to support the just discussed concept. In this new material, Mg 2+ is almost exclusively bonded to nitrogen atoms of (SCN) − , and the sulfur atoms coordinate to Li + .…”

“…The migration of , i.e. the hopping of Li + cations, is considered to occur via next nearest neighbors (adjacent sites) which was used to construct the defect model in Part I, 1 and is depicted in Fig. 8a.…”

“…According to the defect model and the derived enthalpies of Li(SCN) ( cf. Table 2 in Part I), 1 the generation by Schottky reaction requires 0.6 eV, and the concentration can be calculated. Local ion hopping occurs with the high frequency migration enthalpy .…”

“…Part I, Fig. 1a) 1 indicates that there might be more mobile compared to Li(SCN). The impedance spectra do not show any sign of an additional high frequency response, and the dielectric constant suggests a very different reorientation behavior of (SCN) − in this system ( cf.…”

“…Anhydrous Li(SCN) is an intrinsically Schottky defective material with lithium vacancies as mobile defects. 1 Based on the thermodynamic and kinetic knowledge of its defect chemistry, we investigate the specific physical mechanism of Li + cation hopping, especially regarding the role of the anisotropic thiocyanate anion (SCN) − .…”