An NMR study of the alkali metal intercalation phase LixTiS2: Relation to structure, thermodynamics, and ionicity

Abstract

The Knight shift and electric quadrupole coupling constant have been measured as a function of lithium concentration in the continuous intercalation phase LixTiS2 where 0⩽x⩽1. These NMR data, when compared with observations of c axis dilation and thermodynamics of this phase, suggest the donation of an appreciable fraction of the Li 2s electron to the TiS2 layers during intercalation, with the fraction diminishing as x increases. The relation of the charge donated to each of the observed quantities is discussed.

Electric field gradient calculations forLixTiS2and comparison withLiBredow1, Heitjans2, Wilkening3 2004Phys. Rev. B956870View full textAdd to dashboardCite

“…36,39,59 This is confirmed by the present theoretical calculations. Besides the close agreement of the calculated and measured structural parameters only for Li oct TiS 2 , also the intercalation energy E I is larger for Li oct than for Li tet (Table III).…”

“…The results for structural, energetic and electronic properties obtained with PWGGA, HFPW, and HF+ PW are summarized in Table VI. At variance with experimentally observed trends, 36,59 the lattice parameters for Li oct are not further decreased when the content is decreased from 0.67 to 0.33. On the other hand, there is a substantial lattice contraction for Li tet with all three methods.…”

“…With all three methods, PWGGA, HFPW, and HF+ PW, the optimized lattice parameters are smaller than for x = 1.0, in accordance with experiments. 36,59 For Li oct , c is decreased by 0.9%-1.0%, and a is decreased by 1.7%-2.6% at PWGGA and HFPW level. With the HF+ PW approach, the decrease of c, by 2.8%, is more pronounced whereas a is almost unchanged.…”

“…Whereas a number of NMR studies focus on the Li dynamics in h-Li x TiS 2 , 4,[9][10][11][36][37][38][39] there are only few experimental NMR investigations available studying static properties. 36,[39][40][41] Since there exist discrepancies for experimental data of the quadrupole coupling constant, in particular for x Ͻ 1, between earlier measurements 36,39 and more recent investigations, 41 we have performed comple- The paper is organized as follows: In Sec. II experimental details are briefly described and our NMR results complementary to those reported in the literature are presented.…”

Li jump process inh−Li0.7TiS2studied by two-timeWilkening1, Heitjans2 2008Phys. Rev. B9881581View full textAdd to dashboardCite

“…11,12 For this reason, it is one of the best investigated intercalation compounds at all. 13,14 Although Li diffusion in Li x TiS 2 was studied in previous years by others using 7 Li NMR relaxation experiments, [15][16][17][18][19] a comprehensive study about the cation dynamics, especially in the regime of ultraslow Li motions which are not accessible by standard measurements, is still missing. Unfortunately, the standard tracer technique is not applicable to study Li dynamics due to the lack of a suitable radioactive Li isotope.…”