Fluorenyllithium Salt Containing Polymers as Single-Ion Conductors

Fluorenyl group substituted polysiloxane and poly(ethylene oxide) (PEO), respectively, have been synthesized. Their lithium salt conductivity behavior is discussed in relation to the solvent separated ion pair, ionic association with polymer chain, as well as the morphology of the media. As long as the metal ions are well separated from their counterions, as in the case of separated fluorenyl lithium ion pair by formation of Li+-THF complex, high dielectric constant medium such as PEO may not be necessary to achieve higher ionic conductivities. As an example, a relatively high single-ion conductivity, ∼5 × 10−6 s cm−1 at 25°C, is observed in fluorenyl-lithium salt containing polysiloxane.