CoO2, the end member of the LixCoO2 solid solution
CoO2, the end member of the LixCoO2 solid solution
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DOI：
10.1149/1.1836594
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发表时间：
1996-03-01
影响因子：
3.9
通讯作者：
Klein, LC
中科院分区：
文献类型：
--
作者：
Amatucci, GG;Tarascon, JM;Klein, LC
虽然LiCoO2作为锂离子电池中有前途的正极材料在过去的15年中得到了广泛的研究，但令人惊讶的是，关于嵌锂材料的电化学特性的许多问题仍然没有答案。其中之一是存在一个端员CoO2相完全锂脱嵌。干塑料锂离子电池技术的使用允许构建原位X射线衍射单元，其允许首次在x值为0和接近0时对Li2CoO2进行结构表征。而不是预期的破坏的核心结构的LiCoO2的结构无序急剧增加，晶体质量的增加发生，因为它接近0。首次分离出端元CoO2相。该相是六方单层相（O1），被认为与CdI2同构，并且具有a = 2.822埃和c = 4.29埃的晶格参数。在锂重新插入时，该相立即转化回三层（O3）脱锂的Li2CoO2型相。电化学研究表明，95%的锂可以在完全脱锂后重新插入到结构中，并且当循环回到4.2 V时，可逆循环性能得以保持。
While LiCoO2 has been widely studied in the past 15 years as a promising positive electrode material in lithium-ion batteries, suprisingly, many questions are still unanswered concerning the electrochemical characteristics of the lithium intercalation material. Among these is the existence of an end member CoO2 phase on complete lithium deintercalation. The use of dry plastic lithium-ion battery technology has allowed the construction of an in situ x-ray diffraction cell which allows structural characterization of Li2CoO2 at x values at and close to 0 for the first time. Instead of the expected destruction of the core structure of LiCoO2 by a drastic increase in structural disorder, an increase in crystallographic quality occurred as It approached 0. For the first time, the end member CoO2 phase was isolated. This phase is a hexagonal single-layered phase (O1) believed to be isostructural with CdI2 and has lattice parameters of a = 2.822 Angstrom and c = 4.29 Angstrom. The phase converted immediately back to a three-layer (O3) delithiated Li2CoO2 type phase on lithium reinsertion. Electrochemical studies show that 95% of lithium can be reinserted back into the structure on complete delithiation and reversible cycling properties are maintained when cycled back to 4.2 V.