鸟巢状分级结构LiFePO_4的合成及其电化学性能研究  

Synthesis and Electrochemical Properties of LiFePO_4 Hierarchically Nest-Like Microstructures

作　　者：黄富勤[1] 唐新村[1] 肖元化[2] 龚美丽[1] 郑贞苗 晋媛[1] 

机构地区：[1]中南大学化学化工学院,长沙410083 [2]郑州轻工业学院材料与化学工程学院,河南省表界面科学重点实验室,郑州450002

出　　处：《无机化学学报》2014年第2期235-241,共7页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.21276286)资助项目

摘　　要：采用溶剂热法,以乙二醇为溶剂,P123为软模板剂,制备了锂离子电池正极材料磷酸铁锂(LiFePO4),其振实密度约为1.2g·cm-3。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)和BET对样品的成分、晶型,形貌和孔结构进行了表征。结果表明:鸟巢状LiFePO4由单晶纳米片组成,具有开放的三维多孔分级结构。通过时间单因素实验探讨鸟巢状分级结构LiFePO4的生长机理,其生长过程可以概括为:成核——定向生长——团聚——定向生长。电化学性能测试结果表明材料在0.1C倍率下充放电时,其首次放电比容量达132.5 mAh·g-1。The cathode material LiFePO4 with tap density of ca. 1.2 g·cm-3 was synthesized by solvothermal method, using P123 as soft template and ethylene glycol as solvent. The composition, crystal shape, morphology and pore structure of the as-prepared samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy （SEM）, high resolution transmission electron microscopy （HR-TEM）, Brunauer-Emmett-Teller （BET）. The results show that the nest-like LiFePO4 consists of single-crystalline nanoplates with an open three-dimensional porous hierarchical structure. A reasonable formation mechanism is proposed based on time dependent experiments. The main evolving process involves the following steps： nucleation, oriented growth, aggregation and oriented growth. The electrochemical testing results show that the initial discharge specific capacities of nest-like LiFePO4 reach to 132.5 mAh·g-1 at 0.1C.

关 键 词：LIFEPO4 溶剂热 机理 鸟巢状 锂离子电池 

分 类 号：O614.111[理学—无机化学] O614.811[理学—化学]