Two-dimensional porous β-Co(OH)2 and Co3O4 hexagonal nanoplates as stable and high-performance anode for lithium-ion batteries

Abstract

The multifunctional β-Co(OH)2 and Co3O4 nanoplates were successfully synthesized using a silicone oil-bath method, which manifests hexagonal-like structures with the existence of interior pores. The two-dimensional (2D) porous β-Co(OH)2 and Co3O4 hexagonal nanoplates (HNPs) were obtained at the reaction temperatures of 80 °C (β-Co(OH)2@80) and 100 °C (Co3O4@100), further calcined at 450 °C. The specific surface areas of 59.6 and 101.8 m2 g−1 were obtained for the β-Co(OH)2 and Co3O4@100 HNPs samples, respectively. Both the samples were utilized as anodes for lithium (Li)-ion batteries. The 2D porous Co3O4@100 HNPs electrode delivered an excellent discharge capacity of 1141 mA h g−1 at 100 mA g−1, whereas 506 mA h g−1 remained for the β-Co(OH)2@80 HNPs electrode. Additionally, the Co3O4@100 HNPs electrode was sustained over 1000 cycles with a discharge capacity of 566 mA h g−1. Furthermore, the Co3O4@100 HNPs electrode showed good rate performance with a discharge capacity of 458 mA h g−1 even at 800 mA g−1. The obtained excellent electrochemical characteristics of Co3O4 electrodes are ascribed to the unique 2D structure with small-sized interior pores, which facilitates Li+ diffusion and enhances structural robustness.