Mo掺杂对Li_4Ti_5O_(12)负极材料电化学性能的影响

Effect of alloying molybdenum on electrochemical properties of Li_4Ti_5O_(12) anode meterials

尖晶石型Li4Ti5O12是一种"零应变"负极材料,它被认为是最具前景的动力锂离子电池负极材料之一。然而Li4Ti5O12较低的电导率限制了它的实际应用。通过对其进行不同价态元素的掺杂改性,以提高Li4Ti5O12材料的高倍率性能和循环性能,并研究了低电位下的电化学行为。研究了高温固相法合成了的Mo6+掺杂Li4Ti5O12的材料,结果表明:Mo6+的掺杂有效地提高了材料的放电比容量,0.1 C时,Li4Ti4.8Mo0.2O12的首次放电比容量高达356.6 mAh/g;Li4Ti4.9Mo0.1O12和Li4Ti4.85Mo0.15O12在6 C下循环100次后的可逆比容量分别为210.8、199.4 mAh/g,在高倍率循环过程中表现出了比Li4Ti5O12高的比容量。但随着掺杂量的增加,循环性能却逐渐降低。

Spinel Li4Ti5O12 was a ＂zero-strain＂ negative-electrode material for lithium-ion battery. It was one of the most promising negative-electrode materials for power lithium-ion batteries. However, practical application of Li4Ti5O12 material with lower conductivity was limited. Li4Ti5O12 materials were modified by doping different valence state elements in order to improve the high rate capability and cycling performance, and the low potential electrochemical behavior was researched. Li4Ti5O12 materials doped with Mo6＋ were synthesized via a solid-state method. The results show that the discharge capacity is improved because of the doped Moe＋. The first discharge capacity of Li4Ti4.sMoo.20 Li4Ti5O12 was 356.6 mAh/g at 0.1 C. The specific capacities of Li4Ti4.9MO0.1O12 and Li4Ti4.85Mo0.15O12 were 210.8, 199.4 mAh/g after 100 cycles at 6 C, respectively, and their specific capacities were higher than that of Li4Ti5O12 during charge-discharge at high rates. But with the increasing of doping level, the cycling performance was gradually dropped.