Lithium environment in PEO-LiClO4 polymer electrolyte

The average local structure around Li cations in a polymer electrolyte, P(EO)(7.5)LiClO4, has been determined by neutron diffraction with Li isotope substitution. In this environment, the Li ions are predominantly coordinated by 4 similar to 5 ether oxygens. The intermediate-range order is enhanced relative to the pure polymer by the expansion of the network on the addition of the salt. The excess volume introduced must play a key role in facilitating the lithium ion conduction.