PEO intercalation in layered chalcogenides

Abstract

Intercalated materials the electronic framework behavior of a semiconducting host lattice with the ionic‐conductivity properties of poyethyleneoxide/alkali‐metal guest species are reported. Such materials are of interest for use in solid‐state high‐energy batteries. Here, layered transition metal chalcogenides serve as the host materials, polyethyleneoxide being intercalated by two different methods.

Intercalation and electrical behavior of Ta xMo1-xS2 (x > 0.5) layered mixed disulfides

“…8,24 The incorporation of this polymer changes, in some cases, the metallic character inherent to the pristine chalcogenides to a semiconducting behavior. The mixed dichalcogenides are also able to directly insert pyridine.…”

“…8,24 The reaction of the LiTa x Mo 1-x S 2 intermediate phases with aqueous solutions of PEO produces a colloidal dispersion of the elemental lamellae of the selected ternary dichalcogenide (exfoliated Ta x Mo 1-x S 2 ) intimately mixed with the polymer that can be recovered by centrifugation. This last process produces the re-stacking of the exfoliated dichalcogenide constituted by the pristine sulfide sheets to which PEO can associate, giving nanocomposite materials.…”

“…In this way, polyoxyethylene compounds, such as crown-ethers and poly(ethylene oxide) (PEO), have been intercalated in MoS 2 . 4,8,[21][22][23][24][25][26] This approach implies an structural distortion that leads to a strong modification of the electronic structure of the host solid. As a consequence, the initial semiconducting MoS 2 becomes a metallic conductor due to the reduction produced by the n-BuLi.…”

“…Another important reason why 2D solids are investigated is their ability to intercalate a large variety of compounds. [1][2][3][4][5][6][7][8][9] In this context, physical properties such as electrical conductivity and electrochemical behavior of layered solids can be deliberately modified by intercalation of organic species. [2][3][4]10,11 Among different 2D solids, the study of layered transition-metal dichalcogenides (LTMDs) has become the subject of an active field of research in solid state physics and chemistry during the last decades.…”

“…The first one is of particular interest because the intermediate compounds (lithiated phases) could be further used to prepare new inorganic-organic materials, similarly to that reported for MoS 2 and other disulfides. 4,8,[21][22][23][24][25]44 The lithium chemical insertion (i.e., the so-called lithiation reaction) was carried out by using n-BuLi, a method broadly used in intercalation chemistry. 6,7 In the same way that observed for MoS 2 , TaS 2 and other dichalcogenides (such as TiS 2 and ZrS 2 ), 45 lithiated phases of the ternary disulfides can be prepared.…”