Graphene-like MoS2/amorphous carbon composites with high capacity and excellent stability as anode materials for lithium ion batteries

Abstract

A facile process to synthesize graphene-like MoS₂/amorphous carbon (a-C) composites was developed. MoS₂/C composites were firstly prepared by hydrothermal method employing sodium molybdate, sulfocarbamide and glucose as starting materials. The graphene-like MoS₂/a-C composites were obtained after annealing at 800 °C in H₂/N₂. The samples were characterized by XRD, SEM, EDS and HRTEM. It was confirmed that in the composites MoS₂ has a structure of single-layer, which is named graphene-like nanostructure. The graphene-like MoS₂ nanosheets were uniformly dispersed in amorphous carbon. The interlaminar distance of the adjacent graphene-like MoS₂ nanosheets in the composites measured was ∼1.0 nm. The mechanism of the formation of the graphene-like MoS₂/a-C composites was investigated. The graphene-like MoS₂/a-C composites exhibited high capacity and excellent cyclic stability used as anode materials for Li-ion batteries. The composite prepared by adding 1.0 g of glucose in hydrothermal solution exhibited the highest reversible capacity (962 mAh g⁻¹) and excellent cyclic stability. After 100 cycles, it still retained 912 mAh g⁻¹. The significant improvements in the electrochemical properties of the graphene-like MoS₂/a-C composites could be attributed to the graphene-like structure of the MoS₂ nanosheets and the synergistic effects of graphene-like MoS₂ and amorphous carbon.