Effect of ball milling and electrolyte on properties of high-voltage LiNi0.5 Mnl.5O4 spinel

Effect of ball milling and electrolyte on the properties of high-voltage LiNi0.5 Mn1.5 O4 was investigated. Ball milling has significant effect on the synthesis and property of LiNi0.5 Mn1.5O4. The X-ray diffraction（XRD） patterns indicate that LiNio.s Mn1.5O4 can＇t be synthesized without ball milling even calcined at 900 ℃. When synthesized with bail milling, LiNi0.5 Mn1.5O4 almost exhibits only one plateau at around 4.7 V. With the increase of ball milling time, the capacity of LiNi0.5Mn1.5O4 increases, but the cycling performance is not highly affected. The electrochemical property of LiNi0.5 Mn1.5O4 highly depends on the electrolyte. The stable and high-voltage-resistant electrolyte is much beneficial to enhancement of electrochemical property of LiNi0.5 Mn1.5O4, such as coulombic efficiency and cycling performance.     

Effect of ball milling and electrolyte on properties of high-voltage LiNi_(0.5)Mn_(1.5)O_4 spinel

1 INTRODUCTIONRecently ,several research groups have repor-ted transition-metal-substituted spinel materials(Li MxMn2 -xO4, M: Cr , Co , Fe , Ni , Cu) withhigh-voltage plateaus above 4 .5 V[1 5]. Amongthese materials ,Li Ni0 .5Mn1 .5O4is the most prom-ising and attractive one because of its good cyclicproperty and relatively high capacity with a plateauat around 4 .7 V[3 ,6].Now, a variety of methods were used forpreparation of Li Ni0 .5Mn1 .5O4,such as solid-statereaction[4 ,7 ,8]…     

高电压锂离子电池LiNi0.5Mn1.5O4的合成及性能

以Li2CO3,NiO和电解MnO2为原料,用固相法合成了LiNi0.5M n1.5O4。采用XRD,SEM和恒流充放电测试研究了合成样品的性能。XRD测试表明,在950℃下加热12h,然后600℃下退火48h,所得样品具有立方尖晶石结构。电化学测试表明,充放电曲线只在4.7V附近存在电压平台,但容量及循环性能有待于提高。     

LiNi0.5Mn1.5O4的合成及性能

以Li2C O3,N iO和电解M nO2为原料,用固相法合成了LiN i0.5M n1.5O4。采用X R D,SEM和恒流充放电测试研究了合成样品的性能。X R D测试表明,在950℃下加热12h,然后600℃下退火48h,所得样品具有立方尖晶石结构。电化学测试表明,充放电曲线只在4.7V附近存在电压平台,但容量及循环性能有待于提高。     

Li2MnSiO4/C复合正极材料的合成及电化学性能

采用溶胶-凝胶法合成了Li2MnSiO4/C复合正极材料,并用TG-DTA,XRD和电化学性能测试对材料进行了表征.前驱体的TG-DTA曲线表明,合成Li2MnSiO4时烧结温度应高于500℃.XRD测试表明Li2MnSiO4具有正交结构,对应Pmn21空间群.将Li2MnSiO4/C组装成扣式电池进行电化学测试的结果表明,600℃烧结10h所得样品性能最好,首次放电比容量达到124.2mAh·g-1,为理论比容量的74.5%;循环30次后放电比容量为71.5mAh·g-1.     

锂离子电池正极材料LiNi0.5Mn1.5O4的制备及性能研究

以Li(CH3COO).2H2O、Ni(CH3COO)2.4H2O、Mn(CH3COO)2.4H2O和H2C2O4.2H2O为原料,聚乙二醇20000为分散剂,采用化学合成法制备了具有立方尖晶石结构的锂离子电池正极材料LiNi0.5Mn1.5O4。通过XRD、SEM和充放电测试对样品进行表征。850℃下焙烧制备的LiNi0.5Mn1.5O4样品电化学性能最佳,在3.5～4.9V电压范围内以0.2、0.5、1、2和5C充放电,其首次放电比容量分别为132.9、117.3、111.2、104.8和91mAh/g,20次循环后容量保持率分别为93.2%、98.9%、97.4%、97.3%和95.5%。