The intercalation compounds Li-0.96(H2O)(0.77)(PEO)(0.63)Ni0.48PS3 and Li-0.94(H2O)(0.92)(PEO)(0.94)Fe0.48PS3 obtained by the insertion of PEO in MPS3 form lithium-polyethylene oxide complexes containing Li+ exchangeable cation in the interlayer space. Polyethylene oxide (PEO) is able to associate interlayer cation increasing the ionic conductivity of NiPS3 and FePS3. These compounds constitute a new family of intercalates MPS3 (M = Ni, Fe) host-layer materials. The new materials were characterized by powder X-Ray diffraction (XRD), Fourier-transformed infrared (FT-IR), differential thermal and thermogravimetric analyses (DTA/TG), energy dispersive X-Ray (EDX), inductively coupled plasma (ICP) and electrochemical impedance measurements. The intercalation compound Li-0.96(H2O)(0.77)(PEO)(0.63)Ni0.48PS3 shows an ionic conductivity of 0.13 mu S/cm, and dc electronic conductivity of ca. 0.1 mu S/cm which is twice that of NiPS3. (c) 2004 Elsevier Ltd. All rights reserved.