Li^+电池正极材料Li_2FeTiO_4/CNTs的制备与电化学性能表征

Synthesis and electrochemical performance of Li_2FeTiO_4/CNTs as cathode materials for Li-ion batteries

采用固相法合成Li_2FeTiO_4正极材料并添加CNTs对其进行复合改性,得到Li_2FeTiO_4/CNTs复合材料。采用X线衍射分析(XRD)、场发射扫描电子显微分析(FESEM)以及电化学测试等手段表征Li_2FeTiO_4正极材料的微观结构和电化学性能。结果表明:固相法合成的Li_2FeTiO_4具有低温单斜结构,添加CNTs后,电化学性能有了明显的提升。在10 m A/g的电流密度下,Li_2FeTiO_4/CNTs首次充放电容量分别为165.8和149.7 m A·h/g,实现了大于1个Li^+的可逆脱出与嵌入;Li_2FeTiO_4/CNTs复合材料具有较好的高倍率性能,1 C下的放电容量为61.8 m A·h/g,而未添加CNTs的Li_2FeTiO_4容量仅为37.5 m A·h/g。

The Li_2FeTiO_4 composite materials were synthesized by a solid phase method and modified by adding multi-walled carbon nanotubes.The electrochemical properties,micro-structures of Li_2FeTiO_4 and Li_2FeTiO_4/ CNTs electrode materials were investigated by X-ray diffraction（ XRD）,field-emission scanning electron microscope（ FESEM） and electrochemical tests. Results indicated that the prepared Li_2FeTiO_4 sample consisted of a monoclinic Li_2FeTiO_4.The prepared Li_2FeTiO_4/ CNTs electrode exhibited high initial charge capacity of 165. 8 m Ah / g and discharge capacity of 149. 7 m A·h / g at a current rate of 10 m A / g,indicated that more than 1 lithium per unit could be reversibly inserted and deintercalated during cycling.At the high rate of 1 C,the Li_2FeTiO_4/ CNTs electrode showed the discharge capacity of61. 8 m A·h / g,while the Li_2FeTiO_4 electrode delivered the discharge capacity of 37. 5 m A·h / g.