Lithium cobalt oxide
Encyclopedia
Lithium cobalt oxide is a chemical compound
commonly used in the positive electrode
s 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 crystal structure is denoted R
m 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. Each cobalt atom is aligned on a common axis with lithium atoms and separated from each lithium atom by a triangle of oxygen atoms as can be seen in the figures. The threefold rotational axis is termed improper because the oxygen triangles are anti-aligned.
Exposure to soluble cobalt salts can lead to Beer Drinker's Cardiomyopathy
. MSDS sheets list lithium cobalt oxide is a potential human carcinogen but indicate "no data available" under the Acute Toxicity heading. However, unlike cobalt(II) salts, this oxide is insoluble in water. Lithium ion batteries contain lithium cobalt oxide and are considered nonhazardous waste. Safety precautions should be taken when handling it.
The compound's usefulness as an intercalation electrode was discovered in 1980 by John B. Goodenough
's research group at Oxford.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
commonly used in the positive electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
s 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
Powder diffraction
Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials.-Explanation:...
, and EXAFS: it consists of layers of lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
that lie between slabs of octahedra
Octahedron
In geometry, an octahedron is a polyhedron with eight faces. A regular octahedron is a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex....
formed by cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....
and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
atoms. The crystal structure is denoted R
m in Hermann-Mauguin notation, signifying a rhombus-like unit cell with threefold improper rotational symmetryImproper rotation
In 3D geometry, an improper rotation, also called rotoreflection or rotary reflection is, depending on context, a linear transformation or affine transformation which is the combination of a rotation about an axis and a reflection in a plane perpendicular to the axis.Equivalently it is the...
and a mirror plane. More simply, however, both lithium and cobalt are octahedrally coordinated by oxygen. Each cobalt atom is aligned on a common axis with lithium atoms and separated from each lithium atom by a triangle of oxygen atoms as can be seen in the figures. The threefold rotational axis is termed improper because the oxygen triangles are anti-aligned.
Exposure to soluble cobalt salts can lead to Beer Drinker's Cardiomyopathy
Cardiomyopathy
Cardiomyopathy, which literally means "heart muscle disease," is the deterioration of the function of the myocardium for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death or both. Cardiomyopathy can often go undetected, making it especially dangerous to...
. MSDS sheets list lithium cobalt oxide is a potential human carcinogen but indicate "no data available" under the Acute Toxicity heading. However, unlike cobalt(II) salts, this oxide is insoluble in water. Lithium ion batteries contain lithium cobalt oxide and are considered nonhazardous waste. Safety precautions should be taken when handling it.
The compound's usefulness as an intercalation electrode was discovered in 1980 by John B. Goodenough
John B. Goodenough
John Bannister Goodenough is an American professor and prominent solid-state physicist. He is currently a professor of mechanical engineering and materials science at the University of Texas at Austin...
's research group at Oxford.