A NEW CLASS OF PEO-BASED SPES - STRUCTURE, CONDUCTIVITY AND APPLICATION TO ALKALINE SECONDARY BATTERIES

A new family of PEG-based SPEs containing potassium hydroxide and wate r was thoroughly investigated in order to better understand the struct ure of these materials and to relate it with the interesting conductin g properties observed (ionic conductivity at room temperature between 5.10(-4) S/cm and 10(-3) S/cm). Several techniques were used, includin g DSC, TGA, X-ray diffraction and optical microscopy. This study revea led the presence of a crystalline complex depending on the composition of the SPEs. Despite great difficulties in performing the ac impedanc e technique with our systems, the conductivity vs temperature was inve stigated from room temperature to approximately 100 degrees C. The app lication of these SPEs to nickel secondary batteries (Ni/Cd and Ni/Zn) was also studied. Some results in terms of cyclability and improvemen t of the behaviour of the zinc electrode are presented. (C) 1998 Publi shed by Elsevier Science Ltd. All rights reserved.