Nature-Inspired, Graphene-Wrapped 3D MoS₂ Ultrathin Microflower Architecture as a High-Performance Anode Material for Sodium-Ion Batteries

Abstract

In response to the increasing concern for energy management, molybdenum disulfide (MoS₂) has been extensively researched as an attractive anode material for sodium-ion batteries (SIBs). The proficient cycling durability and good rate performance of SIBs are the two key parameters that determine their potential for practical use. In this study, nature-inspired three-dimensional (3D) MoS₂ ultrathin marigold flower-like microstructures were prepared by a controlled hydrothermal method. These microscale flowers are constructed by arbitrarily arranged but closely interconnected two-dimensional ultrathin MoS₂ nanosheets. The as-prepared MoS₂ microflowers (MFs) have then been chemically wrapped by layered graphene sheets to form the bonded 3D hybrid MoS₂-G networks. TEM, SEM, XRD, XPS, and Raman characterizations were used to study the morphology, crystallization, chemical compositions, and wrapping contact between MoS₂ and graphene. The ultrathin nature of MoS₂ in 3D MFs and graphene wrapping provide strong electrical conductive channels and conductive networks in an electrode. Benefitting from the 2 nm ultrathin crystalline MoS₂ sheets, chemically bonded graphene, defect-induced sodium storage active sites, and 3D interstitial spaces, the prepared electrode exhibited an outstanding specific capacity (606 mA h g^-1 at 200 mA g^-1), remarkable rate performance (345 mA h g^-1 at 1600 mA g^-1), and long cycle life (over 100 cycles with tremendous Coulombic efficiencies beyond 100%). The proposed synthesis strategy and 3D design developed in the present study reveal a unique way to fabricate promising anode materials for SIBs.