Nanoporous MoS 2 /C Composites for High Performance Lithium Ion Battery Anode Material

Monodisperse MoS2/Graphite Composite Anode Materials for Advanced Lithium Ion Batteries

Traditional graphite anode material typically shows a low theoretical capacity and easy lithium decomposition. Molybdenum disulfide is one of the promising anode materials for advanced lithium-ion batteries, which possess low cost, unique two-dimensional layered structure, and high theoretical capacity. However, the low reversible capacity and the cycling-capacity retention rate induced by its poor conductivity and volume expansion during cycling blocks further application. In this paper, a collaborative control strategy of monodisperse MoS₂/graphite composites was utilized and studied in detail. MoS₂/graphite nanocomposites with different ratios (MoS₂:graphite = 20%:80%, 40%:60%, 60%:40%, and 80%:20%) were prepared by mechanical ball-milling and low-temperature annealing. The graphite sheets were uniformly dispersed between the MoS₂ sheets by the ball-milling process, which effectively reduced the agglomeration of MoS₂ and simultaneously improved the electrical conductivity of the composite. It was found that the capacity of MoS₂/graphite composites kept increasing along with the increasing percentage of MoS₂ and possessed the highest initial discharge capacity (832.70 mAh/g) when MoS₂:graphite = 80%:20%. This facile strategy is easy to implement, is low-cost, and is cosmically produced, which is suitable for the development and manufacture of advance lithium-ion batteries.

Boosting Redox-Active Sites of 1T MoS2 Phase by Phosphorus-Incorporated Hierarchical Graphene Architecture for Improved Li Storage Performances

Hybridizing and architecting two kinds of 2D nanomaterials are attractive for energy storage applications. Herein, the chemical and electronic coupling of redox active 1T MoS₂ phase with hierarchical phosphorus-doped graphene architecture (HMPGA) is accomplished by the strong interactions of 2D hybrid colloids. The spectroscopic analyses on the crystal structure, surface morphology, and composition confirm the efficient doping of phosphorus and the hybridization interaction of 1T MoS₂ with the phosphorus-incorporated graphene. The resulting HMPGA anode shows significant improvement in battery performances. The specific capacity is delivered to 1194 mAh g^-1 at 100 mA g^-1 with a cyclability of 93.3% over 600 cycles. This improvement is ascribed to the multicoupling effect arising from the abundant redox-actives sites of 1T MoS₂ phase boosted and stabilized by hierarchically architected, phosphorus-doped graphenes.

Ultra-Thin ReS2 Nanosheets Grown on Carbon Black for Advanced Lithium-Ion Battery Anodes

ReS2 nanosheets are grown on the surface of carbon black (CB) via an efficient hydrothermal method. We confirmed the ultra-thin ReS2 nanosheets with ≈1-4 layers on the surface of the CB (ReS2@CB) by using analytical techniques of field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The ReS2@CB nanocomposite showed high specific capacities of 760, 667, 600, 525, and 473 mAh/g at the current densities of 0.1 (0.23 C), 0.2 (0.46 C), 0.3 (0.7 C), 0.5 (1.15 C) and 1.0 A/g (2.3 C), respectively, in conjunction with its excellent cycling performance (432 mAh/g at 2.3 C; 91.4% capacity retention) after 100 cycles. Such LIB performance is greatly higher than pure CB and ReS2 powder samples. These results could be due to the following reasons: (1) the low-cost CB serves as a supporter enabling the formation of ≈1-4 layered nanosheets of ReS2, thus avoiding its agglomeration; (2) the CB enhances the electrical conductivity of the ReS2@CB nanocomposite; (3) the ultra-thin (1-4 layers) ReS2 nanosheets with imperfect structure can function as increasing the number of active sites for reaction of Li+ ions with electrolytes. The outstanding performance and unique structural characteristics of the ReS2@CB anodes make them promising candidates for the ever-increasing development of advanced LIBs.