The significance of the Li2MnO3 component in 'composite' xLi2MnO3 • (1-x)LiMn0.5Ni0.5O2 electrodes
The significance of the Li2MnO3 component in 'composite' xLi2MnO3 • (1-x)LiMn0.5Ni0.5O2 electrodes
复制标题
DOI：
10.1016/j.elecom.2004.08.002
复制
发表时间：
2004-10-01
影响因子：
5.4
通讯作者：
Thackeray, MM
中科院分区：
文献类型：
--
作者：
Johnson, CS;Kim, JS;Thackeray, MM
研究了0.3Li(2)MnO(3)的电化学行为。0.7LiMn(0.5)Ni(0.5)O(2)“复合”电极在锂电池中充电至大于或等于4.5V时，与酸预处理电极的行为进行了比较。当充电到5V时，0.3Li(2)MnO(3)中的锂都可以被提取出来。0.7LiMn(0.5)Ni(0.5)O(2)在两个不同的步骤中生成Mn0.65Ni0.35O2产物，第一步主要对应于从电极结构中提取锂并伴随着Ni2+氧化成Ni4+，第二步对应于从电极结构中电化学去除Li2O。该电极在5.0至2.0V与Li-0之间循环时，可提供可充电容量>；250mAh/g；高容量和循环稳定性归因于在此电压范围内电极中的高锰(IV)含量。酸处理显著降低了电池初始充/放电循环的库仑效率。研究了0.3Li(2)MnO(3)的电化学行为。0.7LiMn(0.5)Ni(0.5)O(2)与标准Li2MnO_3电极进行了比较。使用双分量表示法XLI(2)MnO(3)的优点。(1-x)LiMn0.5Ni0.5O2取代了等效层状记号Li[Lix/(2+x)Mn(1+x)/(2+x)Ni(1-x)/(2+x)]O-2，用于监测电极在电化学充放电过程中发生的成分变化。(C)2004爱思唯尔B.V.保留所有权利。
The electrochemical behavior of 0.3Li(2)MnO(3) . 0.7LiMn(0.5)Ni(0.5)O(2) 'composite' electrodes, when charged to potentials greater than or equal to4.5 V in lithium cells, has been compared with the behavior of electrodes that were preconditioned by acid treatment. When charged to 5 V, all the lithium can be extracted from 0.3Li(2)MnO(3) . 0.7LiMn(0.5)Ni(0.5)O(2) in two distinct steps to yield a Mn0.65Ni0.35O2 product, the first step corresponding predominantly to lithium extraction from the electrode structure with the concomitant oxidation of Ni2+ to Ni4+, and the second to the electrochemical removal of Li2O from the structure. The electrode delivers a rechargeable capacity >250 mAh/g when cycled between 5.0 and 2.0 V vs. Li-0; the high capacity and cycling stability are attributed to the high manganese (IV) content in the electrode over this voltage range. Acid-treatment significantly reduces the coulombic inefficiency of the initial charge/discharge cycle of the cells. The electrochemical behavior of 0.3Li(2)MnO(3) . 0.7LiMn(0.5)Ni(0.5)O(2) is compared with that of standard Li2MnO3 electrodes. The advantage of using the two-component notation xLi(2)MnO(3) . (1 - x)LiMn0.5Ni0.5O2 instead of the equivalent layered notation Li[Lix/(2 + x)Mn(1 + x)/(2 + x)Ni(1 - x)/(2 + x)]O-2 to monitor the compositional changes that occur in the electrode during electrochemical charge and discharge is highlighted. (C) 2004 Elsevier B.V. All rights reserved.