Patent ID: 6730435
Filing Date: 2004-05-04
Classification: H01M,Y02E,Y10T

Abstract:
An active material for non-aqueous secondary battery wherein the active material can be doped/undoped with an alkali metal ion; the active material is a compound particle comprising three or more of constituting elements, and contains an element A selected from Li, Na, K, Mg, Ca, Sr, Ba, B, Al, Ga, In, Si, Zr, Sn, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ag and Zn as one of the constituting elements; the particle has a region where the concentration of element A is decreasing continuously in the direction of from the particle surface to the particle core; and the ratio (d/D) of the mean width (d) of this region towards a depth direction extending from the surface toward the center of the particle to the mean radius (D) of the particle is 0.001