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|Section2= |Section3= }} Lithium cobalt oxide (LiCoO2) is a chemical compound commonly used in the positive electrodes of lithium-ion batteries. The structure of LiCoO2 is known theoretically and has been confirmed with techniques like x-ray diffraction, electron microscopy, neutron powder diffraction, and EXAFS: it consists of layers of lithium that lie between slabs of octahedra formed by cobalt and oxygen atoms. The space group is in Hermann-Mauguin notation, signifying a rhombus-like unit cell with threefold improper rotational symmetry and a mirror plane. More simply, however, both lithium and cobalt are octahedrally coordinated by oxygen. These octahedrons are edge-sharing, and tilted relative to the layered structure. The threefold rotational axis (which is normal to the layers) is termed improper because the triangles of oxygen (being on opposite sides of each octahedron) are anti-aligned. Batteries produced with LiCoO2 cathodes, while providing higher capacity, are more reactive and have poorer thermal stability than chemistries such as the newer lithium-nickel-cobalt-aluminum-oxide types. This makes LiCoO2 batteries susceptible to thermal runaway in cases of abuse such as high temperature operation (>130 °C) or overcharging. At elevated temperatures, LiCoO2 decomposition generates oxygen, which then reacts with the organic electrolyte of the cell. This is a safety concern due to the magnitude of this highly exothermic reaction, which can spread to adjacent cells or ignite nearby combustible material. The compound's usefulness as an intercalation electrode was discovered in 1980〔 〕 by John B. Goodenough's research group at Oxford. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lithium cobalt oxide」の詳細全文を読む スポンサード リンク
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