球形Li_4Ti_5O_(12)/C复合材料的制备及其性能研究

Preparation and Characterization of Spherical Li_4Ti_5O_(12)/C Composite

以TiCl4和导电碳黑为原料,通过"外凝胶"法制备出掺碳球形前驱体,再通过一定的热处理后制备出了锂离子电池球形Li4Ti5O12/C复合负极材料。采用XRD、SEM、比表面及电化学性能测试等分析手段表明,掺碳抑制了Li4Ti5O12晶粒的生长,增大了比表面积,提高了材料的反应动力学性能;掺碳后Li4Ti5O12的振实密度有所降低,但仍明显高于采用传统固相反应法和溶胶-凝胶法制备的非球形产品,掺5%碳的Li4Ti5O12振实密度可达1.71g/cm3;当充放电倍率为1.0C时,在1～3V之间充放电,其首次放电比容量高达144.2mAh·g-1,经过100次充放电循环后,其放电比容量仍有118.2mAh·g-1。

The spherical precursor containing carbon is prepared via an ＂outer gel＂ method, using TiCl4 and C as the raw material. Spherical Li4Ti5O12/C anode material is synthesized by heat treatment. The investigation of XRD, SEM, BET testing and the determination of the electrochemical properties shows that carbon mixed into spherical Li4Ti5O12 particles can restrain the growth of Li4Ti5O12 crystal grains and increase the specific surface area. Thus, the chemical reaction kinetics performance of Li4Ti5O12 material has been greatly improved. The tap-density of the Li4Ti5O12/C product decreases a little, but it is still much higher than non-spherical Li4Ti5O12. The tap-density of additive 5% carbon Li4Ti5O12 is as high as 1.71 g/cm^3, whose initial discharge capacity is as high as 144.2 mAh·g^-1 and it is still 118.2 mAh·g^-1 after 100 cycles at 1.0 C current, between 1.0 and 3.0 V versus Li.lithium secondary battery Li4Ti5O12 tap-density spherical additive carbon