Co^(3+)掺杂对Li_4Ti_5O_(12)结构及性能的影响

The effect of Co^(3+)-doping on structure and performance of Li_4Ti_5O_(12)

以钛酸正丁酯、碳酸锂和三氧化二钴为原料,采用高能球磨辅助固相法及原位包覆技术合成了负极材料尖晶石型Li4Ti4.95Co0.05O12。通过XRD、SEM、充放电和循环伏安测试等,对材料进行分析。高能球磨辅助固相法及原位包覆技术可阻止Li4Ti5O12颗粒团聚、提升颗粒的分散度;Co3+掺杂不会改变晶体结构,但提高了材料的高倍率性能及循环稳定性。在1.0～3.0 V以2.0 C、5.0 C、10.0 C和20.0 C倍率充放电,Li4Ti4.95Co0.05O12的首次放电比容量分别为146.7 mAh/g、135.5mAh/g、113.5 mAh/g和67.2 mAh/g,经过100次循环,可逆容量基本未衰减。

Anode material Co^3＋ -doped Li4 Ti5O12 was synthesized from tetrabutyl titanate, Li2 CO3 and Co2O3 by high-energy ball-miUing assisted solid-state method and in-situ coating technique. The materials were analyzed by XRD, SEM, charge-discharge and cyclic vohammetry tests. The high-energy ball-milling assisted solid-state method and in-situ coating technique could prevent the aggregation of Li4Ti5O12 particles,increase the dispersion of particles. The rate capability and cycle performance of Li4Ti5O12 were improved by Co^3＋ -doping, while the crystal structure was not changed. When charged-discharged in 1.0 - 3.0 V with the rate of 2. 0 C,5.0 C, 10. 0 C and 20. 0 C, the initial specific discharge capacity of Li4Ti4.95 Co0.05 O12 was 146.7 mAh/g, 135.5 mAh/g, 113.5 mAh/g and 67.2 mAh/g,respectively. After 100 cycles,there was almost no reduction in reversible capacity.