Influence of the electronic configuration of the central metal ions on catalytic activity of metal phthalocyanines to Li/SOCl2 battery

The relative energy of Li/SOCl2 battery whose electrolyte contains the transition metal phthalocyanines is used to evaluate the catalytic activity of the compounds. The energy of Li/SOCl2 battery whose electrolyte contains transition metal phthalocyanines-tetracarboxylic acid (MPcTc) and metal phthalocyanines-tetrasulfonic acid (MPcTs) (M = Mn2+, Ni2+) increases by approximately 62–106%, the energy of Li/SOCl2 battery whose electrolyte contains MPcTc and MPcTs (M = Fe2+, Co2+) increases by approximately 32–52%, and the energy of Li/SOCl2 battery whose electrolyte contains CuPcTc and CuPcTs is similar to that of the cell in the absence of these complexes. It shows that the electronic configuration of the central metal ion strongly influences the catalytic activity of metal phthalocyanine to Li/SOCl2 battery. To the same ligand, the compound whose central metal ion with electronic configuration d9 is inactive; the compound whose central metal ion with electronic configuration d4 or d8 exhibits relatively high catalytic activity; and the compound whose central metal ion with electronic configuration d5 or d7 exhibits relatively low catalytic activity. Three possible routes of catalytic reduction of SOCl2 by transition metal phthalocyanine compound are proposed to interpret the results.