SYNTHESIS AND PROPERTIES OF A NEW (PEO)(X)[NA(H2O)]0.25MOO3 NANOCOMPOSITE

Mono- and bi-layers of polyethylene oxide (PEO) have been incorporated into the interlayer gap of A(x)MoO(3), to give ordered (PEO)(x)[Na(H2 O)(n)]0.25MoO3 nanocomposites (x=0.40, mono-; or 0.90, bi-) with inter layer distances of 12.9 and 15 Angstrom, respectively. The driving for ce for the insertion reaction arises from the solvation of the cations by the PEO, together with the increase in entropy resulting from disp lacement of water molecules from the interlamellar region. We propose a model for the structure of the monolayer and bilayer composites base d on X-ray diffraction, C-13/Na-23 solid-state NMR and IR data. We hav e carried out a preliminary comparative study of the electrochemical i nsertion of lithium into the two polymer nanocomposites by using the m aterials as cathodes in rechargeable lithium batteries. Li can be reve rsibly inserted into both materials. Lithium ion transport is substant ially enhanced in the bilayer nanocomposite as a result of PEO incorpo ration, compared with the monolayer nanocomposite. The monolayer compo site also shows a pronounced decrease in cell capacity on cycling by c omparison to the bilayer.