| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery having high safety, especially high safety in high temperature overcharge by suppressing the oxidation decomposition of an electrolyte solvent on the surface of positive active material particles. <P>SOLUTION: In the nonaqueous electrolyte secondary battery equipped with a positive electrode, a negative electrode, and a nonaqueous electrolyte, a compound containing an alkali metal and fluorine, and at least one kind of element selected from phosphorus, oxygen, and hydrogen is formed in at least one part on the surface of positive active material particles and the interface between the particles. The compound is Li<SB>x</SB>PF<SB>y</SB>O<SB>z</SB>(0<x<4; 0<y<6; 0<z<4), NaHF<SB>2</SB>or KHF<SB>2</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
