Template‐Assisted Synthesis of Honeycomb‐Like CoFe 2 O 4 /CNTs/rGO Composite as Anode Material for Li/Na‐Ion Batteries

Abstract CoFe 2 O 4 is a fascinating anode material due to its high theoretical capacity. However, the low electronic conductivity, limited electrochemical kinetics and huge volume expansion lead to poor electrochemical performance. Here, the CoFe 2 O 4 /CNTs/rGO ternary composite with a honeycomb‐like structure (PS‐CFO/CNTs/rGO) has been synthesized via a spray drying method assisted by polystyrene (PS) soft template. The rational 3D porous structure design not only enhances the transport capacity of Li/Na ions, but also provides buffer spaces for alleviating volume expansion, resulting in rapid electrochemical kinetics and improved electrode integrity during cycling. In particular, to improve the electrochemical performance, a facile pre‐treatment process combining heat‐treatment and pre‐sodiation treatment is first developed for the anode materials of sodium‐ion batteries (SIBs). As a result, at 1 A g −1 after 365 cycles, the pronounced capacity of PS‐CFO/CNTs/rGO composite can be maintained at 750 mAh g −1 for lithium‐ion batteries (LIBs), and after 5000 cycles, maintained at 195 mAh g −1 for the SIBs.