Pressure-Assisted Synthesis of Highly Crystalline 1T''-Li_x MoS₂

Li_x MoS₂ is not only a lithium battery material, but is also an important precursor for the synthesis of MoS₂ nanomaterials. Current syntheses of MoS₂ , such as in n-butyllithium/LiBH₄ or electrochemically, are not satisfying in terms of defined stoichiometry and crystallinity, so an accurate experimental crystal structure determination of this important and widely used material has been long awaited. A high-pressure/high-temperature synthesis yielded highly crystalline 1T''-Li_x MoS₂ (x=1, 1.333). 1T''-LiMoS₂ crystallizes in the space group P $$ with a=6.2482(3) Å, b=6.6336(3) Å, c=6.7480(3) Å, α=119.321(2)°, β=90.010(2)° and γ=90.077(2)°. The arrangement of Mo atoms within the b-c-plane confirmed a predicted Peierls distortion. A similar atom distribution pattern to that of Mo is also observed for the lithium atoms. Calculation of bond valence site energies gave an activation barrier of 1.244 eV for 2D lithium-ion migration. For x=1.333, a phase-pure synthesis was achieved.