LAUSR

Abstract Three-dimensionally ordered macroporous (3DOM) CoCr 2 O 4 was synthesized by a colloidal crystal templating route and used as an anode material for lithium ion batteries. Benefiting from the porous structure and smaller particle size, the 3DOM-CoCr 2 O 4 anode exhibits a high specific capacity and excellent rate capability. After an initial specific capacity decrease from 1588 to 709 mAh g −1 during the first three cycles at 50 mAh g −1 , the capacity exhibits an increasing trend in subsequent cycles. After 100 cycles, a high specific capacity of 1218 mAh g −1 is achieved, which is much higher than that of non-templated n-CoCr 2 O 4 (499 mAh g −1 ). Even at a very high current density of 3000 mA g −1 , a specific capacity of 328 mAh g −1 could be obtained. The impact of calcination temperature for 3DOM-CoCr 2 O 4 composites on electrochemical performance is also explored, and possible electrochemical processes involving CoCr 2 O 4 during charging and discharging are proposed in this work. During the charge process, oxidation may occur not only from Co 0 to Co 2+ , but also partly from Co 2+ to Co 3+ . It is also found that the 3DOM architecture of the CoCr 2 O 4 compounds can be preserved even after 100 charge and discharge cycles.