NOVELTY - Electrolyte solution comprises magnesium chloride, and does not contain lithium. The electrolyte solution is used for battery comprising a positive electrode (2) containing carbon and silicon, a negative electrode (10) comprising metal electrode containing magnesium, electrolyte solution layer, separator (8) provided between positive electrode and negative electrode, and collector electrode.    USE - Electrolyte solution used for manufacturing electrolyte (all claimed) of secondary battery e.g. all-solid-type lithium secondary battery, zinc-air battery, magnesium air cell, zinc-sealed battery, and magnesium-sealed battery used as power supply of portable device e.g. mobile telephone, personal computer, motor vehicle, and smart grid.    ADVANTAGE - The secondary battery containing the electrolyte solution has energy density increased to 500 mWh/g, high charge/discharge characteristics, high capacity, and high consistency and is lightweight, and safe to use. Airtight is maintained after laminating the unit battery in series. The battery is highly active since it suppresses the generation of heat from the component material of electrolyte, and is economical. Lithium used in lithium secondary battery has excellent flame retardant characteristics and corrosion resistance.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) manufacture of electrolyte solution, which involves measuring magnesium chloride, dissolving measured anhydrous magnesium chloride in pure water, stirring, and homogenizing;    (2) electrolyte (7), which is obtained by mixing aqueous electrolyte solution and water glass, and gelatinizing. The electrolyte is used for battery containing positive electrode containing stabilizer and porous carbon, negative electrode containing metal or alloy (5) for oxidation-reduction reaction, and adjuvant comprising metal compound and/or compounds containing carbon and main component of semiconductor e.g. N-type semiconductor, electroconductive coating material, adhesive agent, and compound containing hydroxyl group; and    (3) manufacture of electrolyte.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of secondary battery.    Positive electrode (2)    Metal or alloy (5)    Electrolyte (7)    Separator (8)    Negative electrode (10)