具有分级结构钛酸锂的制备及其储锂性能研究

Preparation and lithium storage property of lithium titanate with hierarchical structure

以商业二氧化钛(P25)和LiOH分别作为钛源和锂源,采用两步水热和进一步煅烧法制备具有分级结构的钛酸锂(LTO)材料,通过改变煅烧温度调控材料初级颗粒的尺寸,采用X射线衍射、扫描电镜以及恒流充放电等方法对所制备LTO材料微观结构和电化学性能进行研究。结果表明:所制备LTO材料具有分级结构,煅烧温度为600℃时所制LTO600的纯度高且初级颗粒尺寸较小,因此表现出优异的倍率和循环性能,其在1C、5C、10C、20C、30C、40C和50C下的比容量分别为148mAh/g、141mAh/g、136mAh/g、133mAh/g、131mAh/g、129mAh/g和126mAh/g,当电流密度达到60C时,其比容量仍高达123mAh/g,同时,其在10C、20C和50C下经500次循环后,容量保持率分别为90.0%、90.1%和88.1%。

Spinel lithium titanate(LTO)with "zero strain" have attracted much attention owing to their stable charge-discharge platform,excellent cycle performances,low cost and friendly environmental.LTO materials with hierarchical structure were prepared by two-step hydrothermal and further calcination method.During the preparation,commercial titanium dioxide and lithium hydroxide were used as titanium and lithium sources,respectively.The microstructure and electrochemical performances of the as-prepared LTO were characterized by X-ray diffraction,scanning electron microscopy and galvanostatic charge-discharge measurement.The results shown that the obtained LTO samples had hierarchical structure.LTO600 obtained at 600℃ had high purity and small primary particles,and exhibited excellent high-rate and cyclic performances.The specific capacities of LTO600 at 1 C,5 C,10 C,20 C,30 C,40 C and 50 C were 148 mAh/g,141 mAh/g,136 mAh/g,133 mAh/g,131 mAh/g,129 mAh/g and 126 mAh/g,respectively.Even at 60 C,the specific capacity was still as high as 123 mAh/g.Moreover,the capacity retention after 500 cycles at10 C,20 Cand 50 Creached 90.0%,90.1% and 88.1%,respectively.