Synthesis and characterization of biphenyl-based lithium solvated electron solutions.

We report on the electric conductivity measurements and FTIR studies carried out on lithium solvated electron solutions (Li-SES) using biphenyl as the electron receptor and tetrahydrofuran (THF) as the solvent. Conductivity measurements carried out on samples with varying compositions of lithium, biphenyl (β), and THF reveal the highest conductivity of 12.0 mS/cm is achieved with the solution composition Li(1.0)β(THF)(8.2) and a metallic behavior. Characteristic fingerprint peaks attributed to the solvated electron solution appear in the FTIR spectra. Also, from the FTIR spectra, we propose a reaction mechanism of lithium reaction with biphenyl in THF in that Li(1)β(THF)(n1) (1 Li atom pairing with 1 biphenyl molecule) is formed first followed by Li(2)β(THF)(n1) (2 Li atoms pairing with 1 biphenyl molecule). A better understanding of the physical properties of the Li-SES is a prerequisite in view of their optimal applications as liquid anodes in lithium batteries.