STADIES FOR SYNTHESIS OF LAYERED SOLIDE SOLUTION TYPE CATHODE MATERIALS AND ITS ELECTROCHEMICAL LITHIUM INTERCLATION BEHAVIOR.

结果表明，在所有成分范围内，层状LiNiO_2与层状Li_2MnO_3形成电活性固溶体。虽然低温相Li2TiO3与Li2MnO3具有相同的结构，但随着钛含量的增加，LiNiO2和Li2TiO3之间的固溶体结构由层状结构转变为岩盐结构，这是由于阳离子混合增强所致。当Ni/Ti=1时，LiCrO_2-Li_2MnO_3和LiCrO_2-Li_2TiO_3固溶体具有相似的电化学和结晶学性质，但LiNiO_2-Li_2MnO_3和LiNiO_2-Li_2TiO_3固溶体具有相似的电化学和结晶学性质，但LiNiO_2-Li_2MnO_3体系与LiNiO_2-Li_2TiO_3体系不同。0.5是电活性材料。高容量LiNi_&lt；1/3&gt；Mn_&lt；1/3&gt；Co_&lt；1/3&gt；O_2是LiNixMnyCo1-x-y&gt；O2中的典型化合物，可作为固体…材料。LiNi_1/2&Gt；Mn_2&Gt；1/2&Gt；O_2与LiCoO_2之间的关系较大。LiNi_&lt；1/3&gt；Mn_&lt；1/3&gt；Co_&lt；1/3&gt；O_2的电化学性质与制备工艺密切相关，我们发现从初始充电曲线的形状可以预测电池的性能。性能下降的根本原因是由于杂质NiO的存在，形成了性能低于纯LiNi_&lt；1/3&gt；Mn_&lt；1/3&gt；Co_&lt；1/3&gt；O_2，的Li_2MnO_3电活性固溶体。为了阐明Mn和Ti在固溶体形成过程中的区别，对LiNi_(？)在研究过程中，具有岩盐结构的完全钛取代化合物LiNi_lt；1/2&gt；Mn_&lt；1/2-x&gt；TixO_2在50℃时的释放量超过150mAh/g。这一事实表明，具有岩盐结构的优良正极材料是可能的，但由于锂的扩散困难，这种结构一直被认为是不合适的。这一发现将为岩盐型电极材料的发展奠定基础。新材料在室温下的电化学性能表现出较低的重现性，然而，通过与Li_2TiO_3形成固溶体，增强了材料的性能。

It is found that layered LiNiO_2 forms electroactive solid solution with similar layered Li_2MnO_3 in the all composition range. Though low temperature phase Li_2TiO_3 has same structure with Li_2MnO_3, the structure of solid solution between LiNiO_2 and Li_2TiO_3 changes from layered structure to rock salt structure as the increase in Ti content because of enhanced cation mixing. On the other hand, LiCrO_2 forms layered solid solution with Li_2TiO_3. The solid solution with Ni/Ti=1 shows largest capacity of more than 170 mAh/g. It is finally confirmed that LiCrO_2-Li_2MnO_3 and LiCrO_2-Li_2TiO_3 solid solutions have similar electrochemical and crystallographic properties, however, LiNiO_2-Li_2MnO_3 system is different from LiNiO_2-Li_2TiO_3 system in both character.LiNiXMn_yCo_<1-x-y>O_2 with lower Mn content of y<0.5 is electroactive material. LiNi_<1/3>Mn_<1/3>Co_<1/3>O_2 with high capacity is a typical compound among LiNi_xMn_yCo_<1-x-y>O_2 and it will be considered as a solid solu … More tion between LiNi_<1/2>Mn_<1/2>O_2 and LiCoO_2. Electrochemical property of LiNi_<1/3>Mn_<1/3>Co_<1/3>O_2 extremely depends on preparation process, and we have found that the battery performance can be predicted from the shape of initial charge curve. The essential reason for lower performance would be due to the presence of impurity, NiO, as a result, electroactive solid solution with Li_2MnO_3, which shows lower performance than pure LiNi_<1/3>Mn_<1/3>Co_<1/3>O_2, is formed.The research for LiNi_<1/2>Mn_<1/2-x>Ti_xO_2 has been carried out in order to clarify the difference between Mn and Ti in the formation of solid solution. In the course of study, complete Ti substituted compound, LiNi_<1/2>Mn_<1/2-x>Ti_xO_2 with rock salt structure, delivers more than 150 mAh/g at 50 ℃. This fact indicates the possibility of excellent cathode materials with rock salt structure, which has been considered unsuitable because of difficulty in Li diffusion. This finding would lead to the development of rock salt type electrode materials. The new material shows low reproducibility in electrochemical property at room temperature, however, enhanced properties are confirmed by the formation of solid solution with Li_2TiO_3. Less