Prussian blues as a cathode material for lithium ion batteries.

Prussian blues (or iron cyanides) and their analogues are attractive in both fundamental studies and industrial applications owing to their chemical and structural diversity. The large open space in their framework provides tunnels and space for the transport and storage of lithium ions. Two Prussian blues were synthesized by a co-precipitation method. The nanosized Fe4 [Fe(CN)6 ]3 and cubic FeFe(CN)6 deliver reversible capacities of 95 mAh g(-1) and 138 mAh g(-1) , respectively. In comparison, FeFe(CN)6 shows cycling and rate performances superior to Fe4 [Fe(CN)6 ]3 .