【摘要】 以四异丙氧基钛酸(TTIP)作为锂离子电池负极材料TiO2合成的钛源,草酸为防止TTIP水解的抑制剂,聚乙烯醇(PVA)为碳源,采用喷雾干燥法结合固相烧结的方法制备出微米级球型TiO2和碳包覆TiO2。利用热重-差热分析(TG-DTA)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和电化学方法对其进行物理表征和电化学性能研究。测试结果表明,400℃下煅烧4 h的TiO2样品为锐钛矿晶型,具有相对最高的比容量,0.1 C电流密度下首圈放电比容量为225.5 mAh/g,充放电效率为95.3%,在不同电流密度下35圈循环后,放电比容量仍可以达到190.3mAh/g,比容量保持率为84.4%。原料中添加10%(质量分数)PVA制备的碳包覆TiO2,在10 C大电流密度下放电比容量提高至114.7 mAh/g,比没有碳包覆的TiO2提高约26.6%,经过20次充放电循环后放电比容量仍为102.3 mAh/g,容量保持率为89.2%。碳包覆TiO2在大电流密度下表现出较佳的比容量及循环性能。更多还原

【Abstract】 Micrometer-level carbon-coated anatase TiO2 used for lithium-ion battery anode materials was successfully synthesized via the spray drying process followed by post-calcination, wherein titanium isopropoxide(TTIP) was employed as the Ti source, oxalic acid was as an inhibitor of TTIP hydrolysis and PVA was as the carbon source. Thermogravimetric diagram and differential thermal analysis(TG-DTA), X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscope(TEM) and electrochemical tests were used to characterize the prepared TiO2. The TiO2 calcined at 400℃ show that the anatase phase, its initial discharge specific capacity was 225.5 mAh/g at 0.1 C and charge-discharge efficiency was 95.5%. After 35 cycles of charge and discharge, the discharge specific capacity was 190.3 mAh/g and the capacity retention was 84.4%. For the carbon-coated TiO2, the discharge specific capacity was 114.7 mAh/g at 10 C and the value was about 26.6% higher than that of the uncoated TiO2; the discharge specific capacity was retained 102.3 mAh/g with capacity retention of89.2% after 20 cycles of charge and discharge. The carbon-coated TiO2 shows significantly better specific capacity and cycle performance at high current density in comparison to the uncoated samples.更多还原