TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The lithium transition metal oxide has lithium transition metal oxide of formula: Li1+xNiyCozMn(1-y-z)MaO2 (I), as main component. The negative electrode active material particles contain graphite coated with amorphous carbon.x=more than 0 and less than 0.2;y=more than 0.1 and less than 0.9;z=more than 0.1 and less than 0.4;a=more than 0 and less than 0.03;andM=Zr, Mo, W, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, Al, B or F.Preferred Properties: The long diameter of the primary particles of lithium transition metal oxide based on scanning electron microscope observation is 0.2 mu m or more. The thickness of the shell portion based on scanning electron microscope observation is 0.1 mu m or more. The positive electrode active material particles have through-hole passing through the shell portion. The particle void content of the positive electrode active material particles is 1-80%. An oil absorption amount of the negative electrode active material particles for linseed oil is 50-60 ml/ 100 g. The ratio (Ca/Cc) between a positive electrode capacity (Cc) calculated by the product of a theoretical capacity per unit mass of the positive electrode active material and the mass of the positive electrode active material, and a negative electrode capacity (Ca) calculated by the product of a theoretical capacity per unit mass of the negative electrode active material and the mass of the negative electrode active material is 1.7-1.9. Preferred Components: The electrode component is provided with an elongated positive electrode in which a positive electrode active material layer of specified width is formed over an elongated positive electrode collector along the lengthwise direction of the collector, and an elongated negative electrode in which a negative electrode active material layer of specified width is formed over an elongated negative electrode collector along the lengthwise direction of the collector. The electrode component is a rolled electrode component having the elongated positive electrode and elongated negative electrode layered in insulated state and rolled in the lengthwise direction.