(中南大学 冶金科学与工程学院,长沙 410083)
摘 要: 以纳米TiO2和Li2CO3为原料,通过固相反应法制备负极材料Li4Ti5O12,研究焙烧温度和时间对合成Li4Ti5O12样品电化学性能的影响。利用TG、XRD、SEM 和充放电测试表征Li4Ti5O12的物理性能和充放电性能。结果表明:焙烧温度的选择比延长焙烧时间对Li4Ti5O12的性能影响更大,提高焙烧温度和延长焙烧时间,都能够促进晶体结构的完整,改善材料的电化学性能;经800 ℃焙烧24 h得到的Li4Ti5O12首次放电容量为167 mA∙h/g,经过80次充放电循环,容量几乎没有衰减;对Li4Ti5O12充电到0.5 V,充电曲线上均观察到明显的极化现象,极化程度同活性物质的颗粒大小和结合情况有关。
关键字: Li4Ti5O12;负极材料;物理性能;电化学性能
(School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract:Anode materials Li4Ti5O12 were prepared by one-step solid-state reaction using Li2CO3 and nano-TiO2 as precursors, and the effects of sintering temperature and time on the performance of Li4Ti5O12 were investigated. The physical properties and charge-discharge performance of Li4Ti5O12 were characterized by TG analysis, XRD, SEM and electrochemical measurement, respectively. The results show that the selection of sintering temperature is more important than extension of sintering time, and the extension of sintering temperature and time can improve the crystal structure and electrochemical performance of Li4Ti5O12. The initial discharge capacity is 167 mA∙h/g for the samples prepared at 800 ℃ for 24 h, and without capacity fading almost after 80 cycles. Polarization is clearly observed on the charge curves of Li4Ti5O12 when charged to 0.5 V, the extent of polarization is related to Li4Ti5O12 particle size and integration of particles.
Key words: Li4Ti5O12; anode materials; physical properties; electrochemical performance