LiNi_(0.5)Co_(0.5)O_2体系的结构稳定化作用和独立充放电机理  

Structural Stabilization Effect and Independent Charge-discharge Mechanism for LiNi_(0.5)Co_(0.5)O_2 System

作　　者：顾大明[1] 张鼎[1] 付宏刚[1] 

机构地区：[1]哈尔滨工业大学应用化学系,哈尔滨150001

出　　处：《无机化学学报》2007年第5期765-770,共6页Chinese Journal of Inorganic Chemistry

基　　金：黑龙江省自然科学基金资助项目(No.E2004-24)。

摘　　要：为了解释锂离子二次电池正极材料LiNi_(0.5)Co_(0.5)O_2具有的优良充放电循环性能和高比容量特征,采用基于密度泛函理论(DFT)的第一性原理计算方法对LiNi_(0.5)Co_(0.5)O_2和LiNiO_2的相关特性进行了研究。结果表明LiNi_(0.5)Co_(0.5)O_2的结构稳定性优于LiNiO2的原因在于充放电过程中体系中Ni、Co离子交替存在的价电子构型t_(2g)~6e_g^0。依据LiNi_(0.5)Co_(0.5)O_2体系中Ni离子和Co离子相互独立的电极反应提出了适用于LiNixCo_1-xO_2(0≤x≤1)体系的独立充放电机理(0.2C、3.0￣4.2VvsLi+/Li),并得到实验的证实。The property of LiNi0.5Co0.5O2 is studied by using the first principle calculation method based on density functional theory （DFT） in order to explain the favorable specific charge-discharge capacity and chargedischarge cyclic performance of the Li-ion secondary battery cathode LiNi0.5Co0.5O2. The study reveals that the structural stabilization of LiNi0.5Co0.5O2 over LiNiO2 during the charge-discharge cycles lies in the alternate existence of valence configurations t2g^6eg^0 of Ni ions and Co ions. Furthermore, independent charge-discharge mechanism （0.2C, 3.0-4.2 V vs Li＋/Li） for the LiNixCo1-xO2 （0≤x ≤ 1） system is proposed based on the independent electrode reaction of Ni ions and Co ions within the LiNi0.5Co0.5O2 system and verified with the experimental data.

关 键 词：正极材料 LiNi0.5Co0.5O2 密度泛函理论 独立充放电机理 

分 类 号：O614.82[理学—无机化学] O614.83[理学—化学]