The Performance And Synthesis Of Functional Material By Mechanochemical Process

The theory of mechanochemical method is to activate raw materials by mechanical energy, change powder structure, and consequently form new phase. Because of its simple process, low cost, low temperature, and friendly to environment, it is called a synthetic process of green environmental protection. Based on the understanding of mechanochemical method theory, a new mechanochemical grinding machine designed by Professor Li Qiang was employed. By using this new machine, we can obtain products only after a few hours of grinding with oxide as the raw materials. In this paper, we research different factors which influence the formation of new phase, such as raw powder filling rate, grinding time, grinding power. And a series of technological parameters are confirmed successfully. The methods of XRD, SEM, BET are used to study phase transformation and morphology.LiMn2O4 has been widely used as the anode materials in lithium ion batteries and supercapacitor electrode materials because of its unique structure. After homogeneously mixing pure Li2CO3 and Mn2O3, we synthesized spinel structure of ultra-fine LiMn2O4 powder successfully by new mechanochemical method. We can obtain pure LiMn2O4 phase under the conditions of 3.0 kw power,88% filling rate and 8h grinding. At the same time, we find out the powder distribute unevenly and the particle size is bigger. To overcome the reunion, we put the product into sanding machine, well-dispersed nano-powders are obtained after 2h' sanding. We make foam nickel electrodes by mixing LiMn2O4 powder, acetylene black and PTFE emulsion according to a certain quality, and research the electrochemical performance in the electrolyte of lmol/L (NH4)2SO4 and lmol/L Li2SO4. Circulation voltammetric curves show LiMn2O4 electrode material has a good capacitance performance and dynamics of reversible. Charging and discharging tests show that LiMn2O4 materials have a higher specific capacity in 0.5 mol/L Li2SO4+ MgSO4 solution. The specific capacity reduces less, and charge-discharge efficiency keep stable after 20 recharge cycles. It's means that the supercapacitor show a better circulation performance.As a kind of excellent semiconductor functional materials, Zn2SnO4 have broad prospect in gas sensors, photoelectric device, photocatalytic degradation etc. After homogeneously mixing pure SnO2 and ZnO, We synthesized spinel structure of ultra-fine Zn2SnO4 powder successfully through mechanochemical, grinding machine. We can obtain Zn2SnO4 under the conditions of 3.0kw power,82% filling rate and 2h grinding. But the powders distribute uneven and the particle size range from 20nm to 500nm. After 2h' sanding, well dispersive and nanoscale powder was received. In addition, we research photocatalytic activity of Zn2SnO4 by using methyl orange and alizarin red solution for goal pollutant in ultraviolet and visible light respectively. We also make film electrod by doctor blade method, assemble DSSC after absorbing N719 or Blueberries anthocyanidins dye to study the electro-optical property. The voltage (VOC) and short-circuit current (ISC) are measured initially. We will study the technology to raise DSSC efficiency through improving preparation electrode and assembling battery technology.