Dopamine-Induced Formation of Ultrasmall Few-Layer MoS₂ Homogeneously Embedded in N-Doped Carbon Framework for Enhanced Lithium-Ion Storage

Abstract

Molybdenum disulfide with a layered structure and high theoretical capacity is attracting extensive attention for high-performance lithium-ion batteries. In this study, a simple and scalable method by freeze-drying of (NH₄)₂MoS₄ and dopamine mixed solutions along with subsequent calcination is developed to realize the self-assembly of hierarchical MoS₂/carbon composite nanosheets via the effect of dopamine-induced morphology transformation, in which ultrasmall few-layer MoS₂ nanosheets were homogeneously embedded into a N-doped carbon framework (denoted as MoS₂@N-CF). The embedded ultrasmall MoS₂ nanosheets (∼5 nm in length) in the composites consist of less than five layers with an expanded interlayer spacing of the (002) plane. When tested as anode materials for rechargeable Li-ion batteries, the obtained MoS₂@N-CF nanosheets exhibit outstanding electrochemical performance in terms of high specific capacity (839.2 mAh g^-1 at 1 A g^-1), high initial Coulombic efficiency (85.2%), and superior rate performance (702.1 mAh g^-1 at 4 A g^-1). Such intriguing electrochemical performance was attributed to the synergistic effect of uniform dispersion of few-layer MoS₂ into the carbon framework, expanded interlayer spacing, and enhanced electronic conductivity in the unique hierarchical architecture. This work provides a simple and effective strategy for the uniform integration of MoS₂ with carbonaceous materials to significantly boost their electrochemical performance.