Solution Synthesis Of Bismuthoxychloride And Manganese-Based Compound Micro/Nanostructures And Their Energy Storage Properties

In this dissertation, controlled synthesis and properties were developed to prepare bismuthoxychloride and manganese-based compounds with porous structures. Regular3D BiOC1microstructutes were synthesized solvothermally and porous MnO2microplates and microspheres, MnCo2O4and CoMnO4hollow microspheres were produced through hydro-/solvo-thermal methods followed by the pyrolysis of the precursors. The electrochemical hydrogen storage properties of BiOC1microstructures were investigated in Ni/H battery model. We also study the behaviors of manganese-based compounds as anode in a rechargeable lithium battery. The main points are summarized as follows:1. Several3D BiOC1microstructures, such as2500nm peonies,1000nm ball-flowers, and3000nm rough spheres are selectively and solvothermally prepared. These microstructures are composed of nanoplate with size of～1000nm,～300nm and～200nm, respectively, the growth surface of which are all (001). Based on the results of the time-depended experiments, we propose the possible forming mechanism as "fast nucleation-oriented attachment-fusion". N2adsorption desorption isotherms demonstrate that the rough spheres possesse the largest special surface area and pore volume, which affect the electrochemical hydrogen storage behavior. Electrochemical tests indicate that the sample with the larger special surface area and pore volume possesses the higher storage capacity of hydrogen. We assumed that hydrogen entered into the interlayer between (001) facets considerring its largest interplanar spacing. In addition, the hydrogen storage study of BiOCl microspheres composed of nanoplates with exposed facet perpendicular to [2(-)21] axis indicates that hydrogen enters into the interlayer. The above results of research have been in press in the international jounal of Journal of Nanoscience and Nanotechnology.2. MnCO3microstructures, including microplates with the average diameter of2.3μm and thickness of about200nm and microspheres with the average diameter of3.1μm stacked with50nm-thick sheets, were hydrothermally prepared in the presence of sodium dodecyl benzene sulphonate (SDBS) and dodecyl sulfonic acid sodium (SDS), respectively. With the as-synthesized MnCO3as precursors followed by annealing at400℃for4h, porous γ-MnO2microplates and microspheres with different pore sizes, which basically remained the initial shapes, were obtained. The former with the narrower pore size diameter and the larger special surface area performs a better behavior for lithium battery. The electrochemical property tests over Li+batteries showed that the initial discharge capacity of the as-prepared γ-MnO2microplates and microspheres were1997mAh·-g-1and1533mAh·g-1. Noticeably, even after100cycles, the discharge capacity of γ-MnO2microplates was still as high as626mAh·g-1, showing the decent cycle behavior. The above results of research have been published in the international jounal of Journal of Alloys and Compounds.3. Porous MnCo2O4and CoMn2O4hollow microspheres were synthesized through the pyrolysis of carbonates, which were obtained solvothermally by tuning the ratio of Mn/Co. Firstly, relatively uniform carbonate microspheres with different components were solvothermally produced; after calcining at a centain temperature, porous hollow microspheres were obtained due to the different diffusion rate of the two metal ions (Kirkendall effect). The X-ray diffraction patterns indicate that MnCo2O4is cubic phase, whereas CoMn2O4is a tetragonal structure. The preliminary electrochemical property tests over Li+batteries showed that the initial discharge capacity of the as-prepared MnCo2O4and COMn2O4hollow microspheres were1473mAh·g-1and1357mAh·g-1. After10cycles, the discharge capacity of the MnCo2O4and CoMn2O4hollow microspheres were978and809mAh-g"1, respectively, indicating their potential application in lithium battery.