采用钛酸四丁酯、硝酸钡和硝酸锶为原料的微波水热法在70℃,10 min的工艺参数下合成钛酸锶钡纳米颗粒;通过对纳米粉体造粒、成型、排胶和烧结等工艺处理制备了钛酸锶钡陶瓷;研究了陶瓷晶粒生长动力学以及烧结温度、烧结时间对陶瓷的影响。采用透射电子显微镜和扫描电子显微镜分别对粉体的形貌和陶瓷的表面形貌进行分析。研究表明,钛酸锶钡基陶瓷晶粒生长机制可以用TPRE模型来描述,确定了晶粒生长激活能为238.6 k J/mol,陶瓷比较适宜的烧结温度为1240℃。
The microstructure and performance of Li4Ti5O12 doped by Mg prepared by hydrothermal method and solid phase method were investigated. Lithium dihydrate, magnesium acetate and tetrabutyl titanate were used as the main raw materials. This study reveals that Mg^2+ has influences on the spherical structure, crystal development of Li4Ti5O12 and the electrochemical performances. The hollow spherical structure is composed of nano-sheet structure and the nano-sheet structure can be affected by the Mg^2+ content. For Li4-xMgxTi5 O12, the sheet structure can be refined with the increment of Mg^2+ content when x value is 0-0.1 and coarsen with the increment of Mg^2+ content when x value is 0.1-0.2. The hollow spherical Li4Ti5O12 powders prepared by hydrothermal method have better performance. The optimal Mgdoped amount of hydrothermal method is 0.1. At 0.1 C, the first discharge capacity of Li3.9Mg0.1Ti5O12 prepared through hydrothermal method at 0.1 C and 10 cycles is 182 and 178 mA hg^-1, respectively.
