Preparation And Electrochemical Properties Of Carbon/Sulfide Self Assembled Composite

Recently, Lithium ion batteries (LIBs) have been successfully utilized in portable electronic devices and electric vehicles for their high energy density and power density.In recent years, lithium resource is becoming increasingly expensive due to the limited resource and heavy demand. Meanwhile, sodium resource, as the most abundant, geographically ubiquitous, and potentially cheap resource in the Earth’s crust and ocean, gives sodium-ion batteries a promising future for the large scale application in electrical energy. Hence researches on sodium ion batteries (SIBs) have gained momentum in recent years.Transition metal compounds have attracted a lot of attention due to their high specific capacity, low cost, and facile producibility. The typical anodes include oxides, sulfides, and fluorides. Among them the metal sulfides have also been regarded as a most promising class of high capacity materials. The newly emerging sodium-metal sulfide batteries,including FeS, FeS2, SnS2, Ni3S2, Sb2S3 have risen to prominence owin g to their high power and energy densities. Iron sulfide, has recently considered by many researchers as a promising anode material because of its high theoretical capacity, high voltage plateau, cost effectiveness,environmental benignity and abundance in nature.However, Iron sulfide suffers greatly from large volume change during the insertion and extraction of Li/Na ions. FeS electrode changes to an agglomerated shape during the charge/discharge processes, and the agglomerated shape does not recover to original one by charge process, which means the irreversible process. In other hand, the low conductivity and sluggish kinetics of FeS always give rise to the inferior electrochemical properties.In this work, we proposed an effective strategy to improve the cyclibality of FeS by diminishing the granularity of FeS and covering them with a carbon layer. A new kind of 3D chrysanthemum-like carbon/FeS composites was synthesized via a surfactant-assisted solvothermal-based approach. The morphology and structure of the CL-C/FeS were mainly characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM). It was found that the prepared CL-C/FeS microspheres posses a 3D chrysanthemum-like structures, which are with average diameter of 15 um. FeS nanosheets and carbon nanosheets stacked closely to form a sheet-on-sheet structure, and this 2D sheet-on-sheet C/FeS nanosheets self-assembled to form a 3D chrysanthemum-like morphology. Due to the unique structure, CL-C/FeS microspheres showed excellent Lithium/sodium-storage performance.