Lithium Environment in Dilute Poly(ethylene oxide)/Lithium Triflate Polymer Electrolyte from REDOR NMR Spectroscopy

摘要

The role of the lithium ion environment is of fundamental interest regarding transport and conductivity in lithium polymer electrolytes.X-ray crystallography has been used to characterize the lithium environment in completely crystalline poly(ethylene oxide) (PEO) electrolytes,but this approach cannot be used with dilute PEO electrolytes.Here,using solid-state NMR data collected with the rotational-echo double-resonance ~(13)C{~7Li} (REDOR) pulse sequence,we have been able to characterize the crystalline microdomains of a PEO-lithium triflate sample with an oxygen/lithium ratio of 20:1.Our data clearly demonstrates that the lithium crystalline microdomains are nearly identical to those of a completely crystalline 3:1 sample,for which the crystal structure is known.