The Effect of Electrode Potential on the Conductivity of Polymer Complexes of Nickel with Salen Ligands

Abstract

The influence of the electrode potential on the electric conductivity of polymer complexes of nickel with salen-type ligands (where salen is N,N′-ethylene-bis(salicylideneimine)) differing by substituents in ligand′s benzene ring is studied in the course of measuring cyclic voltammograms. The highest electron conductivity is observed for the film of poly[N,N′-ethylene-bis(3-methoxysalicylideneiminato) nickel(II)] (poly[Ni(CH₃OSalen)]) in 1 M LiPF₆ solution in the ethylene carbonate-diethylcarbonate mixture (EC: DEC = 1: 1). Poly[N,N′-ethylene-bis(3-methyl-salicyleneiminato) nickel(II)] (or poly[Ni(CH₃Salen)]) was found to have the widest potential range of electronic conductivity. Conditions are selected for synthesizing films from solutions of the corresponding monomers in 1 M LiPF₆ EC: DEC electrolyte. The electrode potential intervals suitable for the use of poly[Ni(CH₃Salen)] as the buffer interlayer between the aluminum substrate and the cathode mass in lithium-ion batteries for protecting the latter against overcharge are found.