溶胶-凝胶-自蔓延燃烧法合成LiNi_(0.5)Mn_(1.5)O_4的性能研究

Study on the property of LiNi_(0.5)Mn_(1.5)O_4 synthesized by sol-gel self-propagating combustion method

采用不同组分锂盐和均匀性较好的溶胶-凝胶-自蔓延燃烧合成法,制备5V级高电位的镍锰酸锂正极材料,以期满足新能源汽车高能量、高功率动力电池的需求。利用X射线衍射仪对该材料的晶体结构进行测定以及物相分析,采用扫描电子显微镜分析样品的显微形貌和微观形态结构,通过能谱仪测定材料的成分,高精度电测仪测试半电池充放电及循环性能,循环伏安法测试材料的电化学性能。结果表明:LiNi_(0.5)Mn_(1.5)O_4材料是尖晶石结构,衍射峰尖锐,结晶程度较好。微观分析表明,产物的微观形态为八面体结构,粒径分布均匀。在室温下首次充放电(0.2C),1.4mol LiOH·H_2O的容量达到127mA·h/g左右,20次循环容量保持率为98%。循环伏安法测试表明样品放电平台在4.6和3.9V。

To meet the power battery with high energy and high power of new energy vehicle,the lithium salt with different components and the sol-gel self-propagating combustion synthesis with good uniformity were used,LiNi_（0.5）Mn_（1.5）O_4 anode material with 5 Vhigh potential was prepared.Using X-ray diffraction the crystal structure and phase of material were analyzed.The morphology and microstructure of sample were analyzed with scanning electron microscopy（SEM）.Through energy dispersive spectrometer（EDS）for the determination of material composition,the electric measuring instrument with high precision for the charge-discharge and cyclic performance of half-cell,and cyclic voltammetry（CV）measurement test for the electrochemical performance of material.The results showed that LiNi_（0.5）Mn_（1.5）O_4 material was the spinel structure,the diffraction peak was sharp,the crystallization degree was better.Microscopic pictures showed that the microstructure of samples was the octahedral structure,and uniform particle size distribution.At room temperature for the first time charge and discharge（0.2 C）,the sample L1.4 capacity reached around 127 mA·h/g.The capacity retention ratio of 20 cycle＇s capacity was 98%.The CV test showed that the discharge platform of sample was between 4.6 Vand 3.9 V.