Magnetic resonance study of water absorption in some peo-lithium salt polymer electrolytes

✍ Scribed by J.P. Donoso; M.G. Cavalcante; T.J. Bonagamba; O.R. Nascimento; H. Panepucci

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 406 KB
• Volume: 40
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(95)00193-i

✦ Synopsis

The effects of water absorption in complexes of poly(ethylene oxide) with lithium salts (LiCIO,, LiBF, and LiAsF,) have been studied by DSC and nuclear magnetic and electron spin resonance techniques. Measurements of the temperature dependence of 'Li and 'H relaxation times (Ti and 7") allow us to examine the greater motional freedom acquired by the Li+ ion and the chains in the hydrated complexes. Additional evidence for the increase of the lithium mobility is provided by the considerable reduction in the 'Li NMR linewidth. Increase in hydration also increase the mobility of the free chains and may allow a volume expansion of the mobile segments, thus reducing the 'H second moment. The ESR study performed on a copper salt-PEO complex reasserts that water competes favorably with the ethylene oxide unit for complexation with the positive ion.