NOVELTY - Non-aqueous secondary battery comprises a cathode (21), an anode (22), and an electrolytic solution. The electrolytic solution includes a non-aqueous solvent, an electrolyte salt, and a disulfonyl compound (I) and a disulfinyl compound (II).    USE - The non-aqueous secondary battery, preferably a lithium secondary battery is useful in a battery pack, an electric vehicle, an electric power storage system and an electric power tool, and as an electric power supply source in an electronic apparatus (all claimed) including portable electronic apparatuses (such as a video camcorder, a digital still camera, a mobile phone, a notebook personal computer, a cordless phone, a headphone stereo, a portable radio, a portable TV and a personal digital assistant), a mobile lifestyle electric appliance (such as an electric shaver), a memory device (such as a backup electric power source and a memory card) and a medical electronic apparatus (such as a pacemaker and a hearing aid), where the electric vehicle is an electric automobile (including a hybrid automobile), the electric power storage system is a home electric power server for storing electric power for emergency and the electric power tool is an electric drill and an electric saw.    ADVANTAGE - The small, light-weight non-aqueous secondary battery exhibits high energy density, good battery performance, improved charge and discharge cycle characteristics and high-temperature conservation characteristics, and reduces the size and the weight and improves the service life of the electronic apparatus.    DETAILED DESCRIPTION - Non-aqueous secondary battery comprises a cathode (21), an anode (22), and an electrolytic solution. The electrolytic solution includes a non-aqueous solvent, an electrolyte salt, and a disulfonyl compound of formula (I) and a disulfinyl compound of formula (II).    R1, R2 = hydrocarbyl (preferably comprising 1-18C-alkyl, 2-18C-alkenyl, 2-18C-alkynyl, 6-18C-aryl or 3-18C-cycloalkyl)), halogenated hydrocarbyl (where halogens include F, Cl, Br and I), oxygen-containing hydrocarbyl (comprising 1-18C-alkoxy, first ester group of formula (-C(=O)-O-R3), ester carbonate group of formula (-O-C(=O)-O-R4), second ester group of formula (-O-C(=O)-R5) or polyether group of formula (-(R6O)n-R7), halogenated oxygen-containing hydrocarbyl (where halogens include F, Cl, Br and I), or group obtained by bonding two or more of the above groups to one another;    X1, X2 = halo (including F, Cl, Br and I);    R3-R5 = alkyl;    R6 = alkylene;    R7 = alkyl; and    n = greater than or equal to 2.    INDEPENDENT CLAIMS are included for:    (1) an electrolytic solution including the non-aqueous solvent, the electrolyte salt, and the disulfonyl compound (I) and a disulfinyl compound (II);    (2) a battery pack comprising a non-aqueous secondary battery, a control section configured to control operation of the non-aqueous secondary battery, and a switch section configured to switch the operation of the non-aqueous secondary battery according to an instruction of the control section;    (3) an electric vehicle comprising a non-aqueous secondary battery, a conversion section configured to convert electric power supplied from the non-aqueous secondary battery into drive power, a drive section configured to operate according to the drive power, and a control section configured to control operation of the non-aqueous secondary battery;    (4) an electric power storage system comprising a non-aqueous secondary battery, electric devices configured to be supplied with electric power from the non-aqueous secondary battery, and a control section configured to control the supplying of the electric power from the non-aqueous secondary battery to the electric devices; and    (5) an electric power tool comprising a non-aqueous secondary battery, and a movable section configured to be supplied with electric power from the non-aqueous secondary battery.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a non-aqueous secondary battery (cylindrical type) including an electrolytic solution.    Spirally wound electrode body (20)    Cathode (21)    Anode (22)    Separator (23)    Cathode lead. (25)