Simple solvothermal synthesis of magnesium cobaltite microflowers as a battery grade material with high electrochemical performances

Abstract In this paper, a simple solvothermal method accompanied with a post annealing process was used to synthesize porous and hierarchical MgCo 2 O 4 microflowers (MFs), which were composed of many tightly connected nanosheets. The entire synthesis process was accomplished without any surfactant or template participation. The specific surface area of MgCo 2 O 4 MFs with mean pore size of 29.6 nm was as high as 71.58 m 2 g −1 . A typical three-electrode system was used to investigate the electrochemical properties of MgCo 2 O 4 MFs-based electrode in 2 M of potassium hydroxide aqueous solution as electrolyte. The results demonstrated that such working electrode delivered a specific capacity of 313.3 C g −1 at 1 A g −1 , and still remained 189.4 C g −1 even at the current density increasing to 16 A g −1 . In addition, the capacity retention reached 74.5% after 5000 cycles at 5 A/g, suggesting its excellent long-term stability. MgCo 2 O 4 MFs with highly specific surface area as well as mesoporous microstructures are significantly beneficial to rapid Faradic reaction, in that it ensures sufficient contact of electrolyte/electrode materials and shortens diffusion paths for ions/electrons, as well as maximizes the number of active sites. The synthesis procedure of MgCo 2 O 4 MFs proposed in this work is simple and cheap, and is expected to be employed for the preparation of other binary metal cobaltite as well.