Nonaqueous electrolyte secondary cell and method of manufacturing the same
AssigneeSanyo Electric Co., Ltd.
InventorsShinya Miyazaki, Nobumichi Nishida
Life of this patent
Estimating the term…
Abstract
The present invention provides a nonaqueous electrolyte secondary cell having a positive electrode comprising mainly of a positive electrode active material, a negative electrode, and a nonaqueous electrolyte. The positive electrode active material is a lithium-containing transition metal composite oxide of a hexagonal crystal system that includes a compound represented by the general formula LiCo1-xMxO2, where M is at least one species selected from the group consisting of V, Cr, Fe, Mn, Ni, Al, and Ti, and x is a decimal number in a range 0<x<1, magnesium, and halogen. In a nonaqueous electrolyte secondary cell having such a construction, the high-temperature characteristics are improved without reducing the cell capacity.
Claims5
A nonaqueous electrolyte secondary cell comprising:
- a positive electrode comprising mainly of a positive electrode active material;
- a negative electrode;
- and
- a nonaqueous electrolyte,
- wherein the positive electrode active material is a lithium-containing transition metal composite oxide of a hexagonal crystal system, the composite oxide comprising:
- a compound represented by a general formula LiCo1-xMxO2, where M is at least one species selected from the group consisting of V, Cr, Fe, Mn, Ni, Al, and Ti, and x is a decimal number in a range 0<x<1;
- magnesium;
- and
- halogen;
- wherein a halogen content in a total amount of the positive electrode active material is in a range of 0.0007 to 5 mass %;
- and
- wherein the magnesium is in an amount necessary to lower the pH of filtrate to below 9.8, the filtrate collected after dispersing the positive electrode active material in water.
A method of manufacturing a nonaqueous electrolyte secondary cell, comprising the steps of:
- preparing a lithium-containing transition metal composite oxide of a hexagonal crystal system containing magnesium and halogen, by mixing a lithium source, a cobalt source, a magnesium source, and a halogen source and calcining the sources, a halogen content in a total amount of the positive electrode active material being in range of 0.0007 to 5 mass %, the magnesium being in an amount necessary to lower the pH of filtrate to below 9.8, the filtrate collected after dispersing the positive electrode active material in water;
- preparing a positive electrode using a positive electrode active material containing the composite oxide;
- preparing an electrode assembly by arranging the positive electrode and a negative electrode with a separator disposed therebetween;
- and
- sealing, after enclosing the electrode assembly and a nonaqueous electrolyte solution in a cell outer casing, openings of the cell outer casing.
Dependencies are inferred from the claim text.