磷酸铁锂单晶水热法生长及其表征  

Hydrothermal Growth and Characterization of LiFePO_4 Crystals

作　　者：张梦雪 任孟德 王金亮 周海涛 雷威[1] 柳成荫 

机构地区：[1]桂林理工大学地球科学学院,桂林541006 [2]中国有色桂林矿产地质研究院有限公司广西超硬材料重点实验室国家特种矿物材料工程技术研究中心,桂林541004

出　　处：《人工晶体学报》2018年第2期254-260,共7页Journal of Synthetic Crystals

基　　金：广西自然科学基金(2015GXNSFAA139264);广西科学研究与技术开发计划(桂科攻1598008-9);广西科技计划(技术创新引导专项)(桂科AC16380040)

摘　　要：运用桂林水热法成功制备出了毫米级磷酸铁锂体晶体,晶体呈六棱柱结构或者呈圆形(around),等长的外观,等大的外表。实验得到LiFePO_4单晶的XRD衍射峰谱,10°~40°范围内的主强峰相较于磷酸锂铁微晶多出(020)面,说明在晶体生长后期主要由(020)面控制,主要成六棱柱属性终止于(010),(200),(101)这三个表面,这些优势面有望在材料的电化学和表面交换性能中发挥重要作用。分析LiFePO_4晶体结构确定锂离子在(010)方向是运动能量最低的通道,所以增大ac方向维度二维片状和缩短b轴方向的尺度结构的LiFePO_4是可以设计合成的。这将使锂离子的扩散速度得到提高,并且使磷酸铁锂材料在倍率性能,电导率,低温性能方面都可得到提升。LiFePO_4晶体在紫外光区大量吸收,在可见光区内出现一个宽的透过带,吸收值较小,大部分光透过,这正是LiFePO_4单晶颜色不深的原因,并且具有良好的透过性。合成的LiFePO_4晶体的点缺陷造成的色心对近红外短波部分980~1700 nm波长的光全部吸收,近红外长波1750~3000 nm光全部透过,LiFePO_4晶体在1000~3000 nm波长范围内的高对称性吸收和透过必将使其在近红外波段窗口器件的应用上有所突破。The single-crystal LiFePO4 was synthesized by Guilin hydrothermal method, and the single crystal of lithium iron phosphate was prepared. The single crystal has a six-prism structure or a crystal with a round shape, isometric appearance. XRD patterns of the single-crystal LiFePO4 was obtained by the experiment. In 10~ to 40~ strong within the scope of the main peak, compared with nm level lithium iron phosphate, mm leve crystal has one more （020） surface. It is indicate that in the later period of crystal growth, mainly controlled by （020） surface, the main six prismatic properties are ending at （010）, （200）, （101） surfaces of three, these advantages face this is expected to be in the exchange of electrochemistry and surface properties play an important role. Based on the analysis of LiFeP04 crystal structure, the geometrical environment of lithium ion diffusion in lithium iron phosphate was analyzed. The lithium ion is diffused in the direction of （010）, so it is possible to propose the design synthesis to reduce the axis of the b axis. To expand the 2-dimensional flaky structure of the ac direction of LiFePO4. It is expected to increase the diffusion rate of lithium ions, thus improving the conductivity, multiplier performance and low temperature performance of LiFePO4 materials. Selected by the single crystal of LiFePO4 in ultraviolet-visible absorption spectrum wavelength range, known LiFePO4 large absorption in the uv area. There is a wide band in the visible area, with a smaller absorption value, and the majority of the light passes through, which is why the color of LiFePQ single crystal is not deep. The hydrothermal growth of LiFePO4 crystals has a good permeability. The color center caused by the point defect of the synthesized LiFePO4 crystal is absorbed by the light of the near infrared short-wave part 980-1700 nm wavelength, and the near-infrared long wave 1750-3000 nm light is all filtered through. The high symmetry absorption and transmission of LiFePO4 crystals 1000-3000 nm w

关 键 词：LiFePO4单晶 水热法 形貌与结构 吸收光谱 

分 类 号：O78[理学—晶体学]