Patent ID: 7105251

Claim:
A nonaqueous secondary battery comprising a positive electrode containing a material capable of reversibly intercalating and deintercalating lithium, a negative electrode containing a composite oxide containing tin represented by formula (3): SnM 3 c M 4 d O t (3) wherein M 3 represents at least two elements selected from the group consisting of Al, B, P, and Si; M 4 represents at least one element selected from the group consisting of elements of groups 1 to 3 of the Periodic Table, and halogen elements; c represents a number of from 0.2 to 2; d represents a number of from 0.01 to 1; provided that 0.2<c+d<2; and t represents a number of from 1 to 6, a nonaqueous electrolyte containing a lithium salt, and a separator, wherein at least the positive electrode has at least one protective layer comprising organic fine particles and inorganic fine particles.