The intercalation compounds Li0,43(PEO)2.4(H2O)1.4K0.57BiP2S6 and Li0.38(PEO)2.1(H2O)1.6K0.62SbP2S6 have been synthesized by the insertion of polyethylene oxide PEO in LiKMP2S6 (M=Bi, Sb), that contained Li+ and K+ exchangeable cations in their interlayer space. The polymer PEO is able to associate interlayer Li+ cation modifying the ionic conductivity of pristine phases. These intercalation compounds constitute a new family of intercalates in the thiophosphate of Bi and Sb with Polyethylene oxide as guest species. They have been characterized by powder X-ray diffraction, FTIR-Raman, DTA/TGA analysis and electrical conductivity measurements. The studied nanocomposite shows values of electrical conductivity (σi) of about 10-6 Ω-1 cm-1 at room temperature.