Preparation Of Transition Metal Oxide(Sulfide)/Carbon Nanofiber Composites And Their Energy Storage Performance

Nowadays,green and sustainable clean energy is a hot topic in scientific research.Among them,rechargeable secondary batteries,including lithium-ion batteries,sodium-ion batteries,lithium-sulphur batteries,and lithium-oxygen batteries,have attracted extensive attention due to their high efficiency,environmental friendliness,and safety.Electrode materials are one of the key factors that determine the electrochemical performance of batteries.Hence,it is of great importance to develop high-performance electrode materials.Electrospinning is a facile,effective,low cost,and scalable method to prepare high-performance electrode materials.In this paper,we developed two transition metal compounds/carbon nanofibers composites and applied to sodium-ion batteries and lithium-sulphur batteries,respectively.1.A flexible MoS₂/carbon nanofibers composite was prepared via the combination of electrospinning and hydrothermal method（denoted as MoS₂@CNFs）.Benefiting from the C-O-Mo bonding between MoS₂ and CNFs and the rational design of the novel structure,including the well-retained 3D interconnected and conductive MoS₂@CNFs networks and expanded（002）plane interlayer space of MoS₂,when applied as anode materials for sodium-ion batteries,the flexible MoS₂@CNFs anode achieves a high reversible capacity(528 mA h g^-11 at 100 mA g^-1),superior rate performance(412 mA h g^-1 at 1 A g^-1),and ultra-long cycle life(over 600 cycles at 1 A g^-1).2.We developed ultrafine MnO nanoparticles encapsulated in N-doped mutil-channel carbon nanofibers by a facile electrospinning method（denoted as MnO/m-NCNFs）.The ultrafine MnO nanoparticles encapsulated in N-doped mutil-channel carbon nanofibers have some advantages:I)the hollow channel formed by the decomposition of PS during the annealed process was beneficial to the high mass loading of S;II)N-doped carbon nanofibers could enhance the electrical conductivity of the composites;III)polar MnO nanoparticles could serve as adsorbents and catalysts for the lithium polysulfides and suppress the shuttle effect.When applied as cathode materials for lithium-sulphur batteries,the S/MnO/m-NCNFs cathode delivered a retain capacity of 648 mA h g^-1 after 50 cycles at 0.1 C with high S mass loading of 70 wt%.