Preparation And Electrochemical Performance Of Manganese Oxide And Sulfide

Because of their composition and nature of diversities,Manganese oxide and sulfide nanoscale materials have broad application prospects in lithium ion battery anode materials and super capacitor electrode materials. In this paper, firstly, microsphere nickel manganese carbonate precursor has been synthesized by co-precipitation. Secondly,MnO @ Ni microspheres and NiS2-MnS hierarchical structures have been prepared by by controlled calcination reduction and solvothermal method, respectively. The phrase,morphology and structure of the samples were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Their electrochemical performances have been investigated. The main research points are summarized as follows:1. Nickel manganese carbonate precursor has been synthesized by co-precipitation method using nickel acetate and manganese acetate as raw materials, sodium bicarbonate as precipitant. Then, MnO @Ni microspheres have been prepared by a controlled calcination reduction process. The result indicates that as anode materials for lithium ion batteries, MnO@Ni microspheres obtained at 1:10 of Ni/Mn mole ratio possessed a superior electrochemical performance to the samples prepared in other Ni/Mn mole ratio.MnO@Ni microspheres show a specific discharge capacity of 851.2 mAh g-1 at 0.1 C and 285.7 mAh g-1 even after 200 cycles at 0.5 C, with a capacity retention of 72%,indicating that they have good cycle stability.2. NiS2-MnS hierarchical structures have been prepared by solvothermal approach using nickel manganese carbonate as precursor, thioacetamide as sulfuration agent. The obtained samples were characterized and their electrochemical performances have been investigated. The results indicate that the sulfuride products prepared at 150? for 12 h possess relatively integral spheres structure. The NiS2-MnS sample with hierarchical structures shows an initial specific discharge capacity of 630.8 F g-1, and 205 F g-1 even after 1000 cycles at 1 Ag-1 with a capacity retention of about 70%. Thus, they exhibit good rate capability and cycle stability.