Positive electrode material and method for manufacturing the same, battery using the positive electrode material and method for manufacturing the same, and electronic device using the battery

Abstract

A positive electrode material has diffraction peaks at 2θ=13.1°±0.2°, 14.0°±0.2°, and 18.4°±0.2° in X-ray diffraction (2θ=5° to 90°) using synchrotron radiation having a wavelength of 1 Å, has a monoclinic crystal structure belonging to a space group P2 1 /c, and is represented by a composition formula Li 2−2x Co 1+x P 2 O 7 (−0.2≤x≤0.2).

What is claimed is: 
     
         1 . A positive electrode material
 having diffraction peaks at 2θ=13.1°±0.2°, 14.0°±0.2°, and 18.4°±0.2° in X-ray diffraction (2θ=5° to 90°) using synchrotron radiation having a wavelength of 1 Å,   having a monoclinic crystal structure belonging to a space group P2 1 /c, and   represented by a composition formula Li 2−2x Co 1+x P 2 O 7  (−0.2≤x≤0.2).   
     
     
         2 . The positive electrode material according to  claim 1 , wherein in the crystal structure, the number of oxygen atoms coordinated to a Co atom is 4 to 5. 
     
     
         3 . The positive electrode material according to  claim 1 , wherein a=8.2 Å, b=13.5 Å, c=9.7 Å, and β=148° are satisfied as lattice constants. 
     
     
         4 . A method for manufacturing a positive electrode material
 having diffraction peaks at 2θ=13.1°±0.2°, 14.0°±0.2°, and 18.4°±0.2° in X-ray diffraction (2θ=5° to 90°) using synchrotron radiation having a wavelength of 1 Å,   having a monoclinic crystal structure belonging to a space group P2 1 /c, and   represented by a composition formula Li 2−2x Co 1+x P 2 O 7  (−0.2≤x≤0.2), the method comprising   heat-treating a mixture of a lithium source, a cobalt source, and a phosphoric acid source.   
     
     
         5 . The method for manufacturing a positive electrode material according to  claim 4 , wherein the heat treatment is performed at a temperature of 420° C. or higher and 520° C. or lower. 
     
     
         6 . The method for manufacturing a positive electrode material according to  claim 4 , wherein the heat treatment is performed in an inert atmosphere. 
     
     
         7 . A battery comprising:
 a positive electrode containing a positive electrode material;   a negative electrode; and   an electrolyte disposed between the positive electrode and the negative electrode, wherein   the positive electrode material   has diffraction peaks at 2θ=13.1°±0.2°, 14.0°±0.2°, and 18.4°±0.2° in X-ray diffraction (2θ=5° to 90°) using synchrotron radiation having a wavelength of 1 Å,   has a monoclinic crystal structure belonging to a space group P2 1 /c, and   is represented by a composition formula Li 2−2x Co 1+x P 2 O 7  (−0.2≤x≤0.2).