NOVELTY - A secondary battery has a positive electrode (21), a negative electrode (22), and an insulating layer capable of moving ions and connected with at least one of positive electrode and negative electrode. The insulating layer contains polymers having one or more nitrogen-containing repeating unit (I)-(VI).    USE - Secondary battery is used as power supply for electronic device, electric vehicle, electrical storage apparatus and electric power system (all claimed). Uses include but are not limited to power supply for mobile telephone or portable information terminal, hybrid car, electric motorbike, etc.    ADVANTAGE - The secondary battery has improved cycle characteristics in high-temperature environment.    DETAILED DESCRIPTION - A secondary battery has a positive electrode, a negative electrode, and an insulating layer capable of moving ions and connected with at least one of positive electrode and negative electrode. The insulating layer contains polymers having one or more nitrogen-containing repeating unit of formulae (I)-(V) and -(C(-R6)=N)r- (VI).    R1-R5=H, or functional group having H, C, N, O, and halo e.g. fluorine, chlorine, bromine and iodine;    several R1,R2,R3,R4,R5,R6=cyclic structure;    m-r=repeating unit number;and    R6=functional group having H, C, N, O, S, and halo e.g. fluorine, chlorine, bromine and iodine, at least 1 or more is cyano.    INDEPENDENT CLAIMS are included for the following:    (1) battery pack, which has exterior which includes the secondary battery, and a control portion for controlling the secondary battery;    (2) electronic device, which receives supply of electric power from the secondary battery;    (3) electric vehicle, which has secondary battery, a converter which receives supply of electric power from the secondary battery, and converts into driving force of vehicle, a control apparatus which performs information processing regarding vehicle control based on the information regarding the secondary battery;    (4) electrical storage apparatus, which has the secondary battery, electrical storage apparatus which supplies electric power to the electronic device connected to the secondary battery; and    (5) electric power system, which receives supply of electric power from the secondary battery or with which electric power is supplied to the secondary battery from electric power generating apparatus or a power network.    DESCRIPTION OF DRAWING(S) - The drawing shows the sectional view of secondary battery. (Drawing includes non-English language text)    Battery can (11)    Insulation board (12,13)    Battery cover (14)    Positive electrode (21)    Negative electrode (22)    Separator (23)