Disclosed are a non-aqueous electrolytic solution, which can improve cycle characteristics when a power storage device is used at high temperature and high voltage, and a power device using the same. The non-aqueous electrolytic solution according to the present invention comprises, in addition to a non-aqueous solvent and an electrolyte salt dissolved therein, a compound represented by the following formula (I):

##STR00001## wherein n is an integer of 1 or 2; and when n is 1, L represents a straight or branched unsaturated hydrocarbon group of which at least one hydrogen atom is optionally substituted by a halogen atom, a cycloalkyl group of which at least one hydrogen atom is optionally substituted by a halogen atom, or an aryl group of which at least one hydrogen atom is optionally substituted by a halogen atom; and when n is 2, L represents a saturated or unsaturated divalent hydrocarbon group which optionally contains ether bond(s), or an arylene group.

Disclosed is a process for one-step preparing electrolyte used for lithium-iron(II) disulfide batteries. The process includes the following steps of: adding iodine-containing precursors into an organic solvent in an inert atmosphere, homogeneously stirring, then adding lithium-containing precursors, stirring and reacting, separating solids to obtain an electrolyte used for lithium-iron(II) disulfide batteries. The process involves one-step synthesizing electrolyte used for lithium-iron(II) disulfide batteries. The whole procedures do not introduce water and have a lower cost. The lithium-iron(II) disulfide batteries prepared by using the electrolyte prepared by the process of the present invention have better properties.

An electrolytic solution includes a sulfone and a magnesium salt dissolved in the sulfone, in which the magnesium salt includes magnesium borohydride (Mg(BH.sub.4).sub.2).

Provided are a non-aqueous electrolyte solution including propylene carbonate (PC) and lithium bis(fluorosulfonyl)imide (LiFSI), and a lithium secondary battery including the non-aqueous electrolyte solution. The lithium secondary battery including the non-aqueous electrolyte solution of the present invention may improve low-temperature output characteristics, high-temperature cycle characteristics, output characteristics after high-temperature storage, capacity characteristics, and swelling characteristics.

Non-flammable electrolyte compositions for lithium metal primary batteries and the cells containing these electrolytes are described. The electrolyte compositions comprise one or more partially or fully fluorinated functionalized short chain polyethers with one or more lithium salts, and may include one or more cosolvents, and may have one or more fire retardants added. Said short chain functionalized fluorinated polyethers have much better ionic conductivity than the alkyl terminated fluorinated polyethers or long chain perfluoropolyethers, which provide superior flame resistance without sacrificing overall battery performance. Heat resistant, non-flammable primary lithium cells are also disclosed.

Provided is an electrolyte solution additive including lithium difluorophosphate (LiDFP), a vinylene carbonate-based compound, and a sultone-based compound. Also, a non-aqueous electrolyte solution including the electrolyte solution additive and a lithium secondary battery including the non-aqueous electrolyte solution are provided. The lithium secondary battery including the electrolyte solution additive of the present invention may improve low-temperature output characteristics, high-temperature cycle characteristics, output characteristics after high-temperature storage, and swelling characteristics.

A cell is provided. The cell includes a cell element including a positive electrode, a negative electrode, an electrolyte and a laminate film including an exterior layer, a metal layer, an interior layer, and a welded layer formed of the interior layer; wherein a thickness of the welded layer is larger than 5 m in a flat portion of the interior layer, wherein the welded layer increases in thickness from the flat portion to an end portion of the welded layer, and wherein when a thickness of the laminate film is t, a thickness of the interior layer is p and a thickness of the laminate film in the welded layer is t1, a following equation is satisfied: t2p2+5<t1<t25 (m).

Provided are a non-aqueous electrolyte solution which includes a lithium salt including lithium bis(fluorosulfonyl)imide (LiFSI) and an additive including a vinylene carbonate-based compound and a sultone-based compound, and a lithium secondary battery including the non-aqueous electrolyte solution. The lithium secondary battery including the non-aqueous electrolyte solution of the present invention may improve low-temperature output characteristics, high-temperature cycle characteristics, output characteristics after high-temperature storage, and capacity characteristics.

The problem to be solved is to provide a liquid electrolyte for a fluoride ion battery which allows a larger capacity of the battery. Solving the problem by providing a liquid electrolyte for a fluoride ion battery including a fluoride salt and a solvent to dissolve the fluoride salt, characterized in that the solvent is an aromatic material having an aromatic cation and an anion, and a molar ratio of the aromatic cation to a fluoride ion is more than 1.

Provided are a carbon fluoride modification method, modified carbon fluoride and a lithium/carbon fluoride battery. The modification method comprises: mixing carbon fluoride with a composite solvent, subjecting same to a modification treatment, and then performing solid-liquid separation, so as to obtain modified carbon fluoride, wherein the composite solvent comprises water and an ether solvent. The composite solvent is used to modify carbon fluoride; and under the synergistic effect of water and the ether solvent, unstable components in a carbon fluoride material can be removed by means of reaction, thereby improving the chemical stability of the carbon fluoride material and reducing side reactions of carbon fluoride with an electrolyte solution, and therefore the storage stability of a lithium/carbon fluoride battery is improved. The modification method is simple and feasible, does not need the step of pre-charging, and is easy to implement and suitable for large-scale production.