Mesoporous FeC2O4 was prepared by dehydration of bulk monoclinic- and micellar orthorhombic FeC2O4 center dot 2H(2)O precursors at 200 degrees C. The micellar material shows nanoribbon shaped particles, which are preserved after dehydration. These solids are used as high-capacity lithium storage materials with improved rate performance. The mesoporous nanoribbons exhibit higher capacities close to 700 mA h/g after 50 cycles at 2C (C = 1 Li h(-1) mol(-1)) rate between 0 and 2 V.