尖晶石LiNi_(0.5)Mn_(1.5)O_4正极材料首周充放电过程的结构与动力学研究  

Structural and Dynamics Studies of Spinel LiNi_(0.5)Mn_(1.5)O_4 Cathode Material during Initial Charge/Discharge Processes

作　　者：王琴[1] 周丽丽[1] 沈重亨 王琪[1] 黄令[1] 李君涛[2] 孙世刚[1] 

机构地区：[1]厦门大学化学化工学院化学系,福建厦门361005 [2]厦门大学能源研究院,福建厦门361005

出　　处：《电化学》2015年第4期312-318,共7页Journal of Electrochemistry

基　　金：国家自然科学基金项目(No.21273184;No.21321062);973项目(No.2015CB251102)资助

摘　　要：以NaOH为沉淀剂,采用共沉淀法制备尖晶石Li Ni0.5Mn1.5O4正极材料,使用X-射线衍射（XRD）、傅里叶转换红外光谱（FTIR）和扫描电镜（SEM）分析材料结构与表面形貌.结果表明,该材料属于空间群的无序尖晶石Li Ni0.5Mn1.5O4材料,由八面体粒子团聚成3～6μm的大粒子.恒电流充放电结果显示,材料在0.1C倍率下首周放电比容量为121.5 m Ah·g-1,经过150周充放电后,材料比容量无明显衰减,其容量保持率为99%.用PITT和原位XRD联用技术研究了充放电过程中材料的结构与锂离子扩散系数之间的关系.PITT法测得材料中锂离子的扩散系数为10-10～10-11cm2·s-1.The spinel Li Ni0.5Mn1.5O4material was synthesized by co-precipitation method with NaOH as a precipitant. The struc- ture and morphology of the as-prepared Li Ni0.5Mn1.5O4materials were characterized by means of XRD, FTIR and SEM. The results indicated that the material belonged to Fd3m space group and consisted of octahedral particles with the sizes of 3 - 6 μm. Electro- chemical tests showed the first discharge specific capacity of 121.5 mAh.g-1 at 0.1C. After 150 cycles, about 99% of reversible ca- pacity was retained for the Li Ni0.5Mn1.5O4 material. A combining potentiostatic intermittent titration technique （PITT） with in-situ XRD measurement was applied for discussing the relationship between lattice parameter and the diffusion coefficient of lithium ion （Dta,） during the first charging-discharging processes. The DL1 value measured by PITT was in the range of 10-10 ～ 10-11·cm2·s-1.

关 键 词：锂离子电池 正极材料 共沉淀方法 锂离子扩散系数 原位XRD 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]