5V正极材料LiNi_(0.5)Mn_(1.5)O_(4-x)F_x的高温固相法制备与表征  

High temperature solid-state synthesis and characterization of 5V anode LiNi_(0.5)Mn_(1.5)O_(4-x)F_x materials

作　　者：罗晶[1] 李建刚[2] 李建军[3] 何向明[3] 

机构地区：[1]北京化工大学化学工程学院,北京100029 [2]北京石油化工学院应用化学系,北京102617 [3]清华大学核能与新能源技术研究院,北京100084

出　　处：《化工新型材料》2013年第1期94-96,共3页New Chemical Materials

摘　　要：通过高温固相法合成了5V正极材料LiNi0.5Mn1.5O4-xFx(x=0、0.025、0.05、0.075和0.1),采用XRD、SEM、电化学阻抗谱(EIS)及充放电测试探讨了煅烧温度与F掺杂量对产品结构与性能的影响。XRD与SEM分析结果表明,产品相纯度、晶粒发育、颗粒形貌大小主要受煅烧温度与F掺杂量的影响。掺杂量x为0.05～0.075,且煅烧温度为850℃时,所制产品为纯尖晶石相,晶粒发育完善,粒径大小适中且分布均匀。电化学测试结果显示,所有样品都表现出较好的循环稳定性,但F掺杂提高了LiNi0.5Mn1.5O4的容量与倍率特性。其中,F掺杂量x=0.05的样品具有最小的膜阻抗和电荷传递阻抗,表现出较高的容量与最佳的高倍率性能,其0.2C放电容量为128.5mAh.g-1,循环40周后其2C容量仍达0.2C容量的93.8%。未掺杂样2C容量只有0.2C容量的71.8%。5V anode LiNi_（0.5）Mn_（1.5）O_（4-x）F_x（x=0,0. 025,0. 05,0. 075 and 0. 1）materials were prepared via high tem- perature solid state reaction. Effects of annealing temperature and F-doping amount on structure and properties of the prod- ucts were investigated by using XRD, SEM, electrochemical impedance spectra（EIS）and charge-discharge tests. XRD and SEM results indicated that the phase purity, crystallinity and particle size of LiNi0. s Mnl. s 04 x Fx depend on both annealing temperature and F-doping amount. The F-doping amount 0. 05～0. 075 products annealed at 850℃ had pure spinel phase with high erystallinity, moderate and uniform particle size. The electrochemical tests showed that all samples exhibited good cycling stability,and F-doping improved the capacity and rate capability of LiNi0. s Mnl. 5 04. The product with F-doping a- mount 0. 05 had the smallest film resistance and charge transfer resistance, and showed higher capacity and the best rate ca- pability. Its 0.2C discharge capacity reached 128. 5mAh ·g^-1 ,and retained 93.8% at 2C after 40 cycles. The 2C/0. 2C ca- pacity ratio of undoped sample only retained 71.80% in the same test condition.

关 键 词：锂离子电池 5V正极材料 LINI0 5Mn1 5O4 F掺杂 

分 类 号：TM912[电气工程—电力电子与电力传动]