不同锂源对高温固相法制备NCM811正极材料储锂性能的影响  

Influence of Lithium Sources on the Lithium Ion Storage Performance of NCM811 Cathode Materials Prepared by High-Temperature Solid-State Reaction Method

作　　者：芦志刚 李延伟[1] 姜吉琼[1] 李伟[1] 姚金环[1] Lu Zhigang;Li Yanwei;Jiang Jiqiong;Li Wei;Yao Jinhuan(Guilin University of Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学,广西桂林541004

出　　处：《稀有金属材料与工程》2021年第10期3757-3764,共8页Rare Metal Materials and Engineering

基　　金：广西自然科学基金(2018GXNSFBA281114,2017GXNSFAA198117)。

摘　　要：采用4种不同的锂盐(LiOH·H_(2)O、Li_(2)CO_(3)、LiNO_(3)、CH_(3)COOLi),以高温固相法制备了LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)正极材料。利用X射线粉末衍射(XRD)和场发射扫描电子显微镜(FESEM)对所制LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)材料的微观结构进行了表征。发现所有合成的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)样品颗粒尺寸均为微米级,具有层状结构(R-3m空间群)。电化学测试结果表明,采用不同锂源制备的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)样品的电化学性能差别很大。其中采用LiOH∙H_(2)O为锂源,经500℃预烧结6 h后,在800℃下烧结16 h获得的样品锂镍混排程度最低,电化学性能最佳。在0.1 C(1 C=180 mA/g)倍率下其可逆比容量高达206.2 mAh/g,在10 C大倍率下,其可逆比容量仍保持有80.9 mAh/g;在0.5 C倍率下100次充放电循环过程中,最高放电比容量为176.2 mAh/g,平均放电比容量为140.1 mAh/g。动力学及电极稳定性分析发现,LiOH∙H_(2)O制备的样品的电化学可逆性最好,Li^(+)扩散系数最大,充放电循环过程中结构稳定性最好。LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode materials were prepared by a high-temperature solid-phase reaction method with four different lithium salts(LiOH·H_(2)O,Li_(2)CO_(3),LiNO_(3),CH_(3)COOLi)as lithium sources.The microstructure of the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)materials was characterized by X-ray powder diffraction(XRD)and field emission electron microscopy(FESEM).The results demonstrate that the particle size of all the four synthesized LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)samples,with a layered structure(R-3m space group),are micrometers.The electrochemical test results show that the electrochemical performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)samples prepared by different lithium sources is very different.Among them,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)sample prepared with LiOH∙H_(2)O as lithium source(pre-sintering at 500℃ for 6 h and sintering at 800℃ for 16 h)exhibits the lowest degree of lithium-nickel mixing and the best electrochemical performance.Its reversible specific capacity is as high as 206.2 mAh/g at a rate of 0.1 C(1 C=180 mA/g),and its reversible specific capacity remains 80.9 mAh/g at a rate of 10 C;during 100 charge-discharge cycles at a rate of 0.5 C,the highest specific discharge capacity is 176.2 mAh/g,and the average specific discharge capacity is 140.1 mAh/g.The analysis of kinetics and electrode stability reveal that the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)sample prepared with LiOH∙H_(2)O as lithium source possesses the best electrochemical reversibility,highest Li^(+)diffusion coefficient,and superior structural stability during charge-discharge cycling.

关 键 词：锂离子电池 NCM811 正极材料 固相烧结 储锂性能 

分 类 号：TM912[电气工程—电力电子与电力传动]