A high capacity lithium secondary battery with excellent safety is provided by suppressing expansion of a negative electrode active material during charge and increasing the content of a heat-resistant resin in a separator relative to conventional one. The lithium secondary battery includes: a negative electrode active material that comprises compound particles containing at least one metal element selected from the group consisting of Si, Sn, Al, and Zn; and a separator that has a first porous layer comprising polyolefin and a second porous layer comprising a heat-resistant resin. The separator contains 10 to 60 parts by weight of the second porous layer per 100 parts by weight of the first porous layer.

Lithium Secondary Battery

A subject for the invention is to improve the cycle characteristics of a high-capacity secondary battery containing an active material packed at a high density, by using a particulate active material having a low aspect ratio. The invention relates to a nonaqueous-electrolyte secondary battery comprising a negative electrode and a positive electrode each capable of occluding/releasing lithium, a separator, and a nonaqueous electrolyte solution comprising a nonaqueous solvent and a lithium salt, characterized in that the separator comprises a porous film made of a thermoplastic resin containing an inorganic filler, and at least either of the following is satisfied: the active material contained in the negative electrode is a particulate active material having an aspect ratio of from 1.02 to 3; and the active material contained in the positive electrode is a particulate active material having an aspect ratio of from 1.02 to 2.2.

Nonaqueous electrolyte secondary battery

Composite materials and methods of forming composite materials are provided. The composite materials described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0 % and less than about 90 % by weight silicon particles, and greater than 0 % and less than about 90 % by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases can be a substantially continuous phase. The method of forming a composite material can include providing a mixture that includes a precursor and silicon particles, and pyrolysing the precursor to convert the precursor into one or more types of carbon phases to form the composite material.

Composite materials for electrochemical storage

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 μm and about 30 μm and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

Silicon particles for battery electrodes

The present invention relates to a binder resin composition for an electrode, including a polyamic acid and a solvent, wherein the polyamic acid is (i) a polyamic acid which includes a tetracarboxylic acid component including 10 to 100 mol % of 4,4′-oxydiphthalic acid and 90 to 0 mol % of 3,3′,4,4′-biphenyltetracarboxylic acid and/or pyromellitic acid and a diamine component including an aromatic diamine having 1 to 4 aromatic rings, (ii) a polyamic acid which includes a tetracarboxylic acid component including 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride and a diamine component including 10 to 90 mol % of p-phenylene diamine and 90 to 10 mol % of 4,4′-diaminodiphenyl ether, or (iii) a polyamic acid which includes a tetracarboxylic acid component including 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride and a diamine component including 40 mol % or more of a bis[4-(4-aminophenoxy)phenyl] compound.

Binder resin composition for electrode, electrode mixture paste, and electrode

This invention provides a negative electrode material for a rechargeable battery with a nonaqueous electrolyte, characterized in that the negative electrode material contains polycrystalline silicon particles as an active material, the particle diameter of crystallites of the polycrystalline silicon is not less than 20 nm and not more than 100 nm in terms of a crystallite size determined by the Scherrer method from the full width at half maximum of a diffraction line attributable to Si (111) around 2θ=28.4° in an x-ray diffraction pattern analysis, and the true specific gravity of the silicon particles is 2.300 to 2.320.

Negative electrode material for rechargeable battery with nonaqueous electrolyte, negative electrode for rechargeable battery with nonaqueous electrolyte, rechargeable battery with nonaqueous electrolyte, and process for producing polycrystalline silicon particles for active material for negative electrode material for rechargeable battery with nonaqueous electrolyte

This invention provides a negative electrode material for a rechargeable battery with a nonaqueous electrolyte, characterized in that the negative electrode material contains polycrystalline silicon particles as an active material, the particle diameter of crystallites of the polycrystalline silicon is not less than 20 nm and not more than 100 nm in terms of a crystallite size determined by the Scherrer method from the full width at half maximum of a diffraction line attributable to Si (111) around 2? = 28.4° in an x-ray diffraction pattern analysis, and the true specific gravity of the silicon particles is 2.300 to 2.320.

Negative electrode material for rechargeable battery with nonaqueous electrolyte, negative electrode for rechargeable battery with nonaqueous electrolyte, rechargeable battery with nonaqueous electrolyte, and process for producing polycrystalline sil

PROBLEM TO BE SOLVED: To obtain a lithium secondary battery negative electrode that is the lithium secondary battery negative electrode which has a superior cycle characteristic and in which active material particles containing silicon alloy are used, and a lithium secondary battery using it. SOLUTION: The lithium secondary battery negative electrode is obtained, in which an active material layer containing a binder and the active material particles containing silicon alloy composed of silicon and at least one kind of metal element are arranged on a surface of a current collector consisting of a conductive metal foil, then this is sintered under a non-oxidizing atmosphere, and in which the active material particles have a first phase 2 composed of the alloy of silicon and the metal element and a second phase 1 composed mainly of silicon, while the first phase 2 has a three-dimensional mesh structure in the active material particles, and the second phase 1 is enveloped in the first phase 2. COPYRIGHT: (C)2009,JPO&INPIT

Negative electrode for lithium secondary battery, and lithium secondary cell

Negative electrode material for rechargeable battery with nonaqueous electrolyte, negative electrode for rechargeable battery with nonaqueous electrolyte, rechargeable battery with nonaqueous electrolyte, and process for producing polycrystalline silcon particle as active ingredient of rechargeable battery negative electrode material

PROBLEM TO BE SOLVED: To provide: a negative electrode material for a nonaqueous electrolyte secondary battery, which contains a negative electrode active material for a lithium ion secondary battery, the negative electrode active material being excellent in cycle characteristics while maintaining high initial efficiency and battery capacity of silicon and being reduced in large volumetric changes during charging/discharging; and a nonaqueous electrolyte secondary battery in which the negative electrode material is used.SOLUTION: A negative electrode material for a nonaqueous electrolyte secondary battery of the present invention contains polycrystalline silicon as a negative electrode active material, the polycrystalline silicon being prepared using silane gas as a raw material. In the negative electrode material, polycrystalline particles in which a crystal organization structure of the polycrystalline silicon is a laminated structure of single crystal particles are used, and a polyimide resin is used as a binder.

Takano Yasuo

Papers

Negative electrode material for rechargeable battery with nonaqueous electrolyte, negative electrode for rechargeable battery with nonaqueous electrolyte, rechargeable battery with nonaqueous electrolyte, and process for producing polycrystalline sil

Negative electrode for lithium secondary battery, and lithium secondary cell

Process for producing polycrystalline silicon particle for active material in negative electrode material for nonaqueous electrolyte secondary battery