To provide a material suitable for a nonaqueous electrolyte battery having high-temperature durability. An ionic complex of the present invention is represented by any of the following formulae (1) to (3). For example, in the formula (1), A is a metal ion, a proton, or an onium ion; M is any of groups 13 to 15 elements. R.sup.1 represents a C.sub.1 to C.sub.10 hydrocarbon group which may have a ring, a heteroatom, or a halogen atom, or N(R.sup.2). R.sup.2 at this time represents hydrogen atom, alkali metal atom, a C.sub.1 to C.sub.10 hydrocarbon group which may have a ring, a heteroatom, or a halogen atom. R.sup.2 can also have a branched chain or a ring structure when the number of carbon atoms is 3 or more. Y is carbon atom or sulfur atom. a, o, n, p, q, and r are each predetermined integers.

##STR00001##

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).

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.

A battery capable of improving cycle characteristics is provided. An anode includes: an anode current collector, and an anode active material layer arranged on the anode current collector, in which the anode active material layer includes an anode active material including silicon (Si), and including a pore group with a diameter ranging from 3 nm to 50 nm both inclusive, and the volumetric capacity per unit weight of silicon of the pore group with a diameter ranging from 3 nm to 50 nm both inclusive is 0.2 cm.sup.3/g or less, the volumetric capacity being measured by mercury porosimetry using a mercury porosimeter.

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).

An electrochemical cell for an accumulator operating according to the principle of forming an alloy with the active material of the negative electrode during the charge process comprising: a negative electrode comprising, as active material, a material alloyable with an element M, M being a metal element; a positive electrode comprising, as active material, a conversion material; an electrolyte comprising at least one salt of M disposed between the negative electrode and the positive electrode.

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.