复合碳源包覆钛酸锂材料及实装18650电池的性能

Composite carbon source coated Li_4Ti_5O_(12) material and performance of 18650 batteries

采用葡萄糖/碳纳米管对实验室制备的钛酸锂进行包覆改性,并选用商业化钛酸锂材料LTO-KDBR做对比,通过对材料的结构分析和电化学性能测试,为钛酸锂材料的产业化应用提供理论依据和指导。XRD测试表明实验室制备的钛酸锂材料LTO和LTO/C-4%与商业化产品LTO-KDBR的Li_4Ti_5O_(12)晶体结构相近,没有显著差别。SEM分析表明LTO和LTO/C-4%材料的颗粒均一性较差,存在2～3μm的较大颗粒,而LTO-KDBR材料为200～300 nm一次颗粒团聚而成。在10 C倍率下,LTO-KDBR的放电比容量为141.60 mAh/g,显著高于LTO和LTO/C-4%的比容量85.93和126.49 mAh/g。采用LTO-KDBR制备的18650电池,充放电循环500次后的放电容量保持率为88.7%,表明钛酸锂材料作为一种新型负极材料具有较好的大倍率充放电性能和长循环寿命。

The laboratory prepared lithium titanate was coated with glucose/carbon nanotubes,and the commercia lithium titanate material LTO-KDBR was selected for comparison.The structure was analyzed and the electrochemical performance test was used for the industrial application of Li4Ti5O12materials.The XRD test results show that the laboratory prepared lithium titanate materials LTO and LTO/C-4%are similar to Li4Ti5O12crystal structure of the commercial product LTO-KDBR,and there is no significant difference.The SEM analysis shows that the LTO and LTO/C-4% materials have poor particle uniformity,and there is larger particles size of 2-3μm,while the LTO-KDBR material is agglomerated with 200-300 nm primary particles.At 10 C,the LTO-KDBR has a discharge specific capacity of 141.60 mAh/g,which is significantly higher than that of LTO and LTO/C-4%of 85.93 and 126.49mAh/g,respectively.The 18650 battery prepared by LTO-KDBR has a discharge capacity retention rate of 88.7% after 500 cycles.It shows that the lithium titanate material has a good large-rate charge and discharge performance and long cycle life as a new negative electrode material.