模板法制备纳米钛酸锂的性能

Performance of nano-lithium titanate prepared by template method

与石墨负极材料相比,钛酸锂(Li_(4)Ti_(5)O_(12))纳米化后可较好地解决离子导电性等问题。利用纳米二氧化钛(TiO_(2))和石墨碎模板剂制备锂离子电池用纳米Li_(4)Ti_(5)O_(12)负极材料,考察烧结气氛、烧结温度、石墨碎模板剂添加量、原料粒度等对产物的影响,以及组装电池的电化学性能。烧结气氛对制备Li_(4)Ti_(5)O_(12)的影响不大。制备粒度一致可控、性能理想的纳米Li_(4)Ti_(5)O_(12)的优化合成条件是:添加10%的石墨碎混合前驱体,干燥后在氮气气氛中、850~870℃下处理4 h,再经500℃空气气氛处理4 h。将优化工艺下制得的纳米Li_(4)Ti_(5)O_(12)组装成锂离子电池,测得直流内阻抗为33.7~36.1Ω,表明制备的Li_(4)Ti_(5)O_(12)离子扩散性较好。常温下以0.7 C充电、0.5 C放电,在1.5~2.9 V循环620次,容量保持率在87%以上,说明循环性能良好。

Compared with graphite anode materials,lithium titanate(Li_(4)Ti_(5)O_(12))nanocrystallization could better solve the problem of ionic conductivity.Nano-Li_(4)Ti_(5)O_(12) anode material for fast charge Li-ion battery was prepared by nano-titanium dioxide(TiO_(2))and graphite scrap template agent.The effects of sintering atmosphere,sintering temperature,contents of graphite scrap template agent,raw material size on the products were investigated,as well as the electrochemical performance of assembled batteries.The sintering atmosphere had little effect on the preparation of Li_(4)Ti_(5)O_(12).The optimal synthesis conditions of uniform controllable particle size and ideal performance nano-Li_(4)Ti_(5)O_(12) were as follows:adding 10%graphite scrap mixed precursor,treating at 850-870℃in nitrogen atmosphere for 4 h after drying,then treating at 500℃in air atmosphere for 4 h.The nano-Li_(4)Ti_(5)O_(12) prepared under the optimized process was assembled into Li-ion battery,the direct current internal impedance was 33.7-36.1Ω,indicating that the prepared Li_(4)Ti_(5)O_(12) had good ion diffusion.Charging at 0.7 C and discharging at 0.5 C at room temperature for 620 cycles in 1.5-2.9 V,the capacity retention rate was above 87%,indicating that the cycle performance was good.