MoS2/SnS2 synergistically cooperate with graphene to construct high-quality lithium storage anode materials

Abstract

The specific capacity of MoS2 is much larger than that of commercial graphite, but it cannot be practically applied due to its poor electrical conductivity and low cycle stability. Although the conductivity of the material can be greatly increased after compounding with graphene, MoS2 will be unevenly distributed on graphene and form agglomeration because of the charge incompatibility caused by negatively charged molybdenum sources of GO and MoS2. Therefore, the capacity of the as-prepared MoS2/graphene material is extremely unstable and decays to a great extent during cycling. In this paper, a three-dimensional layered structure of MoS2/SnS2 and graphene (MoS2/SnS2-GS) as anode material for sulfur-doped lithium-ion batteries were prepared by a one-pot hydrothermal method. Sn4+ is a bridge connecting two anionic materials, neutralizes negatively charged GO through electrostatic interaction, and adsorbs MoO42-. Furthermore, the heterostructure of MoS2/SnS2 provides a faster and more efficient channel for Li+. Moreover, graphene with high surface area and excellent electrical conductivity allow the electrolyte to provide much fuller access to enter materials, which promotes the transport of Li+. Sulfur doping has a strong effect on surface activation, resulting in a significant increase in surface adsorption and chemical kinetics. Consequently, MoS2/SnS2-GS exhibits excellent capacity and cycling performance as anode material for Lithium-ion batteries (LIBs), maintaining a specific capacity of 2007.4 mAh g−1 at 0.1 A g−1 (100 cycles), and 3224.3 mAh g−1 at 0.5 A g−1 (600 cycles). The preparation method of MoS2/SnS2-GS material provides a great reference for the development of anode materials for disulfide LIBs.