Molecular wiring of LiMnPO4 (olivine) by ruthenium(II)-bipyridine complexes

LiMnPO4 (olivine) was surface-modified by two different complexes: Ru-bis(4,4′-diethoxycarbonyl-2,2′-bipyridine)(4,4′-dicarboxylate-2,2′-bipyridine) and Ru-bis(4-carboxylic acid-4′-carboxylate-2,2′-bipyridine)(4,4′-dinonyl-2,2′bipyridine). These complexes have redox potentials of 4.45 and 4.25 V vs. Li/Li+, respectively, and are both active for molecular wiring of LiMnPO4. The surface-confined Ru(II)/Ru(III) redox reaction propagates across the monolayer via hole-hopping, allowing a subsequent chemical delithiation of the underneath olivine towards MnPO4. The activity of LiMnPO4 is about half of that of LiFePO4 (olivine) at similar experimental conditions.