Revealing the influence of conversion-type Co3O4 dimensionality on cyclic and rate performance for lithium storage

Cobalt tetraoxide (Co3O4) is regarded as a promising anode material for Li-ion batteries owing to its high theoretical capacity (890 mAh g−1), simple preparation, and controllable morphology. Nanoengineering has been proven to be an effective method for producing high-performance electrode materials. However, systematic research on the influence of material dimensionality on battery performance is lacking. Herein, we prepared Co3O4 with various dimensionalities (one-dimensional (1D) Co3O4 nanorod (NR), two-dimensional (2D) Co3O4 nanosheet (NS), three-dimensional (3D) Co3O4 nanocluster (NC), and 3D Co3O4 nanoflower (NF)) using a simple solvothermal heat treatment method, and their morphologies were controlled by varying the precipitator type and solvent composition. The 1D Co3O4 NR and 3D samples (3D Co3O4 NC and 3D Co3O4 NF) exhibited poor cyclic and rate performances, respectively, while the 2D Co3O4 NS exhibited the best electrochemical performance. The mechanism analysis revealed that the cyclic stability and rate performance of the Co3O4 nanostructures are closely related to their intrinsic stability and interfacial contact performance, respectively, and the 2D thin-sheet structure can achieve an optimal balance between the two, resulting in the best performance. This work presents a comprehensive study on the effect of dimensionality on the electrochemical performance of Co3O4 anodes, providing a new concept for the nanostructure design of conversion-type materials.