Formation of ordered macroporous ZnFe2O4 anode materials for highly reversible lithium storage

In this paper, three-dimensionally ordered macroporous (3DOM) ZnFe2O4 (ZFO) was prepared via a templating method with polystyrene (PS) colloidal crystals, and used as highly reversible anode material for lithium ion batteries. In order to study influence of the macropore diameter on a cyclic behavior, 3DOM ZFO anode materials with two different macropore diameters of 160 and 55 nm were prepared. The 3DOM ZFO with a pore diameter of 160 nm (ZFO@160) delivered a high discharge capacity of ca. 1165.8 mAh g(-1) at the initial cycle, as compared with those of 3DOM ZFO with 55 nm macropore (ZFO@55, ca. 1112.3 mAh g(-1)) and ZFO nanoparticles (ZFO NPs, ca. 925.6 mAh g(-1)). Moreover, a reversible capacity of 1143.7 mAh g(-1) for the 3DOM ZFO@160 electrode was stably retained even after 100 cycles. The 3DOM ZFO@160 electrode also revealed much improved cycling performance, coulombic efficiency and rate capability, compared to the 3DOM ZFO@55 and ZFO NPs electrodes. These enhanced electrochemical properties could be ascribed to effective pore dimension with wide-spread channels, which could offer an efficient Li+ flux and a facile strain relaxation.