Lithium intercalation behavior of iron cyanometallates

Abstract

Abstract Iron cyanometallates having a formula, M 6− m n + [Fe m + (CN) 6 ] n (M=V, Mn, Co, Ni, Cu) were prepared and their charge–discharge behavior was discussed. In the V–Fe complex, average discharge potential is about 3.6 V corresponding to reduction of V 3+ , whereas the Mn, Co, Ni, and Cu complexes show similar discharge potential around 3.3 V that is resulted from reduction of [Fe 3+ (CN) 6 ] 3− unit in the lattice. The specific capacity of V, Mn, Co, Ni complexes show about 60–80 mA h g −1 , but copper complex indicates almost double capacity, ca. 140 mA h g −1 . This is explained by considering the capacity caused by Cu 2+ to Cu + reduction in addition to [Fe 3+ (CN) 6 ] 3− →[Fe 2+ (CN) 6 ] 4− reduction.