Polypyridine complexes of iron used as redox shuttles for overcharge protection of secondary lithium batteries

The 2,2′-bipyridyl and 1,10-phenanthroline complexes of iron, which show oxidation potential not, vert, similar0.7 V more positive than that of ferrocene, were studied for their possible use as redox shuttles for the overcharge protection of secondary lithium batteries. The shuttle voltage was found to be around 3.8–3.9 V. The electrochemical stability of these complexes at the electrodes of lithium batteries was also investigated.