Patent ID: 6692665
Filing Date: 2004-02-17
Classification: C01G,C01P,H01M,Y02E

Abstract:
A lithium manganese oxide spinel, comprising:lithium, manganese and a metal element other than lithium and manganese; wherein said lithium manganese oxide spinel satisfies formula (A): (xâˆ’1)+y+z=2â€ƒâ€ƒ(A); wherein x, z and y represent molar ratios of lithium, manganese and said metal element other than lithium and manganese, respectively; wherein x=1 to 1.5, y=0.005 to 0.5, and z is a balance; wherein said lithium manganese oxide spinel has a ratio (I0ppm/I500ppm) of a main peak intensity at 5Â±40 ppm to a main peak intensity at 525Â±40 ppm which falls within formula (B): I0ppm/I500ppm&lE;0.65y+0.02â€ƒâ€ƒ(B); wherein each main peak intensity is obtained from an NMR spectrum measured by 7Li-NMR measurement using a 4-mm Magic Angle Spinning (MAS) probe; wherein a &pgr; pulse echo method is employed as a pulse sequence; wherein said 7Li-NMR measurement proceeds at a resonance frequency of 155.43 MHz; a measuring range of 1 MHz; at a MAS spinning number of 15 kHz; at a measuring temperature of 25Â° C.; using a 0.1 M aqueous solution of LiCl as a chemical shift reference for 0 ppm; wherein said &pgr; pulse echo method comprises a 90-degree pulse, a waiting time &pgr;, a 180-degree (&pgr;) pulse, a waiting time &pgr; and an observation; wherein a measuring pulse in said pulse echo method has a width of 1 &mgr;s for 90 degrees, and of 2 &mgr;s for 180 degrees; a delay time &pgr; of 67 &mgr;s which is a reciprocal of said MAS spinning number of 15 kHz; and a repeating period of 64 sec; wherein said NMR spectrum is subjected to peak dividing using a Lorentz fitting function; and an offset baseline correction; wherein fitting of said NMR spectrum is conducted with the assumption that there is one main peak at each of 5Â±40 ppm and 525Â±40 ppm, treating other bands as side bands, to obtain said main peak intensity.