NOVELTY - An electrical device consists of an electric power generation element (21) having a positive electrode having positive electrode active material layer (15) containing positive electrode active material, a negative electrode having negative electrode active material layer (13) containing negative electrode active material, and a separator (17). The coating amount of negative electrode active material layer is 3-11 mg/cm2. The solid solution positive electrode active material contains lithium-nickel-manganese-cobalt complex oxide (III).    USE - Electrical device e.g. lithium-ion secondary battery (claimed) and capacitor is used as driving power supply and auxiliary power supply. Uses include but are not limited to mobile telephone, notebook personal computer, motorbike, passenger car, truck, bus, light car, and electric train.    ADVANTAGE - The electrical device has excellent rate characteristics and high initial stage discharge capacity.    DETAILED DESCRIPTION - An electrical device consists of an electric power generation element having a positive electrode having positive electrode active material layer containing positive electrode active material formed in the surface of a positive electrode electrical power collector (12), a negative electrode having negative electrode active material layer containing negative electrode active material on the surface of an anode collector (11), and a separator. The coating amount of negative electrode active material layer is 3-11 mg/cm2. The negative electrode active material satisfies the relation: ( alpha )(SiOx)+( beta )(carbon material) (I), where SiOx is a mixture of amorphous silicon dioxide particles and silicon particles, x is number of oxygen which satisfies the valence of silicon, alpha and beta is content (wt.%) of components in the negative electrode active material layer, ( alpha )+( beta ) is 80-98 (including 80 and 98), alpha is 3-40 (including 3 and 40), and beta is 40-95 (including 40 and 95). The particle surface of solid solution positive electrode active material contains an element (M) chosen from aluminum, zirconium, titanium, niobium, boron, sulfur, tin, tungsten, molybdenum, and vanadium. The positive electrode active material satisfies the relation: e(solid solution positive electrode active material) (II), where e is 80-98 wt.% which is the content of components in positive electrode active material layer. The solid solution positive electrode active material contains lithium-nickel-manganese-cobalt complex oxide (III), where z is number which satisfies the valency of oxygen, a+b+c+d is 1.5, d is 0.1-0.4 (including 0.1 and 0.4), a+b+c is 1.1-1.4 (including 1.1 and 1.4), and (M)/(a+b+c) is 0.002-0.05 (including 0.002 and 0.05).    DESCRIPTION OF DRAWING(S) - The drawing shows the cross-sectional view of nonaqueous electrolyte lithium-ion secondary battery.    Lithium-ion secondary battery (10)    Anode collector (11)    Positive electrode electrical power collector (12)    Negative electrode active material layer (13)    Positive electrode active material layer (15)    Separator (17)    Electric power generation element (21)