Layer-stacked cobalt ferrite (CoFe 2 O 4 ) 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 (CoFe 2 O 4 ) 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 (∼2 μm) 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.