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

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.