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).

The present invention relates to an electrolyte for a lithium battery and a lithium battery comprising the same. The electrolyte includes a non-aqueous organic solvent, a lithium salt, and a first additive capable of forming a chelating complex with a transition metal and which is stable at voltages ranging from about 2.5 to about 4.8 V.

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.

A lithium primary cell includes an electrode group and a non-aqueous electrolytic solution. The electrode group includes a positive electrode, a negative electrode, and a separator, in which the positive electrode and the negative electrode are wound with the separator interposed therebetween. In the electrode group, an area where the positive electrode and the negative electrode face each other is 250 cm.sup.2 or more and 350 cm.sup.2 or less. The positive electrode includes a positive electrode mixture including manganese dioxide and a boron compound. The negative electrode includes lithium metal or a lithium alloy. The non-aqueous electrolytic solution includes ethylene carbonate. A content of the boron compound in the positive electrode is 0.5 parts by mass or more and 2 parts by mass or less in terms of boron with respect to 100 parts by mass of the positive electrode mixture. A content of the ethylene carbonate in the non-aqueous electrolytic solution is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the manganese dioxide.

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.

A positive electrode active material having high capacity and excellent cycle performance is provided. The positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charge and discharge as compared with those of a known positive electrode active material.

A positive electrode active material having high capacity and excellent cycle performance is provided. The positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charge and discharge as compared with those of a known positive electrode active material.

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.

A positive electrode active material having high capacity and excellent cycle performance is provided. The positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charge and discharge as compared with those of a known positive electrode active material.

An electrolyte composition comprising: a) a solvent comprising: a mixture of at least two saturated cyclic carbonates, at least one of these saturated cyclic carbonates being fluorinated, at least one ether, said at least one saturated cyclic carbonate representing at most 1.5% by weight of the solvent, said at least one ether representing at least 40% by weight of the solvent; b) at least one lithium salt other than lithium difluorophosphate; c) lithium difluorophosphate in an amount representing from 0.1 to 1% by weight relative to the sum of weight of the solvent and weight of said at least one lithium salt. The use of this composition in an electrochemical cell comprising a lithium anode allows increased performance of the cell when it is discharged under a strong current at low temperature, and limited self-discharging when in operation at ambient temperature.