NOVELTY - An electrical device consists of electric power generation element (21) provided with cell layer (19) containing positive electrode, negative electrode and electrolyte layer (17). The positive electrode consists of positive electrode active material layer (13) provided on positive electrode collector (11) and the negative electrode consists of negative electrode active material layer (15) provided on negative electrode collector (12). The layer (13) contains lithium manganate and lithium compound chosen from lithium cobaltate, lithium nickelate and/or lithium iron phosphate.    USE - Electrical device e.g. nonaqueous electrolyte lithium ion secondary battery, electrical double layer capacitor, hybrid capacitor and lithium ion capacitor. Uses include but are not limited to mobile telephone, notebook personal computer, electric vehicle, hybrid electric vehicle, fuel cell vehicle and hybrid fuel cell electric vehicle.    ADVANTAGE - The electrical device has high energy density and improved cycle characteristics.    DETAILED DESCRIPTION - An electrical device consists of electric power generation element provided with cell layer containing positive electrode, negative electrode and electrolyte layer. The positive electrode consists of positive electrode active material layer provided on positive electrode collector and the negative electrode consists of negative electrode active material layer provided on negative electrode collector. The layer (13) contains 0-80 %mass lithium manganate and 20-100 %mass lithium compound chosen from lithium cobaltate, lithium nickelate and/or lithium iron phosphate. The layer (15) contains lithium titanium complex oxide as negative electrode active material. The ratio of capacitance (A) of the positive electrode having electric potential with respect to lithium of 2.5-4.3 V and capacitance (B) of the negative electrode having electric potential with respect to lithium of 2.5-1.0 V, is 0.95 or more.    DESCRIPTION OF DRAWING(S) - The drawing shows the cross-sectional view of the nonaqueous electrolyte lithium ion secondary battery.    Lithium ion secondary battery (10a)    Positive electrode collector (11)    Negative electrode collector (12)    Positive electrode active material layer (13)    Negative electrode active material layer (15)    Electrolyte layer (17)    Cell layer (19)    Electric power generation element (21)