不同合成方法对LiMn_(1.5)Ni_(0.5)O_(4)正极材料性能的影响  

Effects of Different Synthesis Methods on the Properties of LiMn_(1.5)Ni_(0.5)O_(4) Cathode Materials

作　　者：宋丹丹 陈浩 曾艳红 詹晖[2] SONG Dandan;CHEN Hao;ZENG Yanhong;ZHAN Hui(Department of Biological and Environmental Engineering,Yueyang Vocational Technical College,Yueyang,Hunan 414000;College of Chemistry and Molecular Sciences,Wuhan University,Wuhan,Hubei 430072)

机构地区：[1]岳阳职业技术学院生物环境工程学院,湖南岳阳414000 [2]武汉大学化学与分子科学学院,湖北武汉430072

出　　处：《绍兴文理学院学报》2024年第8期72-78,共7页Journal of Shaoxing University

基　　金：湖南省教育厅科学研究优秀青年项目“生物质材料浸出锂离子电池正极材料有价金属回收的研究”(23B1099)。

摘　　要：采用固相法、溶胶-凝胶法合成LiMn_(1.5)Ni_(0.5)O_(4)。其中固相法前驱体采用高能球磨机细化颗粒,并采用整体升温和阶梯升温两种方式制备LiMn_(1.5)Ni_(0.5)O_(4),通过XRD表征发现合成的样品均不含有杂质。SEM表征显示通过高能球磨处理后的固相法制备的材料颗粒比溶胶-凝胶法小。其中阶梯升温固相法合成的LiMn_(1.5)Ni_(0.5)O_(4)循环稳定性较好,可能是因为退火过程中使得Fd3m结构中的少量Mn^(3+)变成Mn 4+转变成P4332结构,Mn^(3+)的量减少使得容量衰减减慢。整体升温固相法(G-LMNO)合成的样品首周放电比容量可达114.5 mAh g^(-1),只比溶胶-溶胶法合成的LiMn_(1.5)Ni_(0.5)O_(4)(S-LMNO)的放电比容量低1.3 mAhg^(-1)。但是其循环性能得到提升,经过50 th循环充放电,整体升温固相法(G-LMNO)合成的样品容量保持率高达98.43%,原因可能是溶胶-凝胶法合成的LiMn_(1.5)Ni_(0.5)O_(4)的粒子尺寸大,使得Li+的扩散路径变长,极化变大而导致循环性变差。Solid method and sol-gel method are used to synthesize LiMn_(1.5)Ni_(0.5)O_(4) material.The precursor synthesized by solid method refines the particles by high-energy ball mill,and two heating ways,i.e.,overall heating and step heating,are used to prepare LiMn_(1.5)Ni_(0.5)O_(4).All the synthesized samples have no impurity as being determined by XRD.Comparison of the SEM images indicted that the solid-state sample had smaller particle than sol-gel sample,and electrochemical test further showed that it has better cycling stability than the latter phase,possibly because during the cooling,a small amount of Mn^(3+)in the Fd3m structure is converted to Mn 4+,thus changing into P4332 structure,and the reduction of the amount of Mn^(3+)slows down the capacity fading.The sample synthesized by overall heating solid method(G-LMNO)discharges specific capacity reaches 114.5 mAhg^(-1) in the initial cycle,while it was 1.3 mAhg^(-1) lower than the capacity discharged by LiMn_(1.5)Ni_(0.5)O_(4)(S-LMNO).However,it has better cycling stability,and after 50 th cycle charging and discharging,the retention rate of the capacity of the samples synthesized by G-LMNO reach 98.43%.The reason may be that the particle size of LiMn_(1.5)Ni_(0.5)O_(4) synthesized by sol-gel method is larger,which makes the diffusion path of Li+longer,polarization larger and cyclic property worse.

关 键 词：高能量密度材料 锂离子电池 LiMn_(1.5)Ni_(0.5)O_(4) 

分 类 号：O64[理学—物理化学]