Layer-stacked cobalt ferrite (CoFe2O4) mesoporous platelets for high-performance lithium ion battery anodes

The extensive volume change and continuous consumption of active electrode materials due to the repeated formation of a solid electrolyte interface (SEI) layer during charge-discharge cycles are two important topics to be considered for the development of new nanostructured electrodes for high-performance lithium ion batteries (LIBs). In this work, layer-stacked cobalt ferrite (CoFe2O4) mesoporous platelets with two different thicknesses are synthesized, and their electrochemical performance as anodes for LIBs is evaluated. We find that the thickness of the platelets has a great impact on the specific capacity and stability. The thicker platelets (similar to 2 mu m) enable a reduction of SEI-induced consumption of active materials and lead to an overall electrochemical performance superior to that of thinner ones. At a high rate of 5 A g(-1), after an initial drop, the capacity of thicker platelets continuously increases in the following 500 cycles and reaches saturation around 950 mA h g(-1), then gradually decreases and remains at 580 mA h g(-1) after 2000 cycles. The high capacitance, outstanding rate performance and stability of thick platelets can be attributed to the special configuration of the layer-stacked mesoporous platelets which provides sufficient interlayer space for volume expansion, and enables the formation of a stable SEI layer during the cycling.