摘要
以CH3COOLi·2H2O和锐钛矿型TiO2为原料,通过直接融盐法合成锂离子电池负极材料Li4/3Ti5/3O4,考察合成条件对材料性能的影响,并通过X射线衍射仪(XRD)和扫描电镜(SEM)对样品进行物相和形貌分析。结果表明,先在70℃保温5h或10h,再在800℃煅烧2h可得到纯相的Li4/3Ti5/3O4粉末,平均粒径在300nm左右,且粒径分布均匀。充放电测试表明在70℃保温5h、800℃煅烧2h得到的样品具有最优异的电化学性能。以0.1C倍率充放电,其首次放电容量达到172(mA·h)/g,接近理论容量,20次循环后,容量仍保持在140(mA·h)/g。与传统的固相法相比,用直接融盐法得到的材料具有较大的锂离子扩散速率、高倍率性能和循环可逆性。
Anode material Li4/3Ti5/3O4 for lithium-ion batteries has been prepared by direct molten-salt method using CH3COOLi-2H2O and TiO2 as raw materials. The effect of synthesis condition on material properties has been studied in the present paper. CH3COOLi-2H2O is working both as solvent and reacting species. Work has been done in order to find the optimal conditions for the synthesis of Lia/3Ti5/3O4. The compounds are characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. It reveals that pure Li4/3Ti5/3O4 powder with average size of 300 nm is obtained by heating the mixture of CH3COOLi-2H2O and TiO2 at 70 ℃ for 5 h or 10 h, subsequently calcines the pretreated mixture at 800℃ for 2h. Galvanostatic tests show that the product heated at 70℃ for 5h and calcined at 800℃ for 2 h exhibits the best electrochemical performance. At a rate of 0.1 C, it delivers an initial capacity of 172 mAhg^-1, and a capacity of 140 mAhg^-1 at the 20th cycle. Comparing with the sample obtained by conventional solid-state route, the material obtained by molten-salt method can display larger diffusion coefficient of lithium ions, higher rate capability and excellent reversibility.
出处
《粉末冶金材料科学与工程》
EI
2009年第6期400-406,共7页
Materials Science and Engineering of Powder Metallurgy
基金
国家自然科学基金资助项目(50772133)
