Sanyo Electric Co., Ltd.

Mitsubishi Chemical Corporation

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Taizou Sunano

Hiroshi Minami

Maruo Kamino

Yoshio Kato

Atsushi Fukui

Tatsuya Akira

Shouichiro Sawa

Kouhei Tuduki

Hidekazu Yamamoto

Takeshi Ogasawara

Minoru Kotato

Youichi Ohashi

Yohei Uchiyama

Kei Kobayashi

Toshio Yanagida

Ayano Toyoda

Kaoru Nagata

Norihisa Yamamoto

Akihiro Kawakita

Kazuto Fukuda

Takuya Sunagawa

Tatsuki Hiraoka

Takao Kokubu

Takaya Tochio

Taiki Satow

Koh Masahara

Mai Yokoi

Yasuo Takano

Hidekazu Tamai

Yasunori Watanabe

Masahiro Shiraga

Yasunobu Iwami

Shouichirou Sawa

Fukui Atsushi

Yuki Suehiro

This positive electrode active material for non-aqueous electrolyte secondary batteries comprises: lithium transition metal oxide particles; a metal compound which contains a metal element M and adheres to the surfaces of the lithium transition metal oxide particles; and a lithium metal compound which contains lithium (Li) and the metal element M and adheres to the surfaces of the lithium transition metal oxide particles. In this connection, the metal element M is composed of at least one substance that is selected from among aluminum (Al), titanium (Ti), manganese (Mn), gallium (Ga), molybdenum (Mo), tin (Sn), tungsten (W) and bismuth (Bi).

Positive electrode active material for nonaqueous electrolyte secondary batteries, method for producing positive electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

In a nonaqueous electrolyte secondary battery containing a silicon material as a negative electrode active material, the initial charge-discharge efficiency is improved. Negative electrode active material particles () according to an embodiment each contain a lithium silicate phase () represented by LiSiO(where 0&#x3c;z&#x3c;2) and silicon particles () dispersed in the lithium silicate phase (). In base particles () each containing the lithium silicate phase () and the silicon particles (), preferably, a peak originating from SiOis not observed at 2&#x3b8;=25&#xb0; in an XRD pattern obtained by XRD measurement of the particles.

Negative electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material has improved initial charge/discharge efficiency. A negative-electrode active material particle () according to an embodiment contains a base particle (), which includes a lithium silicate phase () represented by LiSiO{0&#x3c;z&#x3c;2} and silicon particles () dispersed in the lithium silicate phase (). The base particle () has a porosity of 25% or less, preferably 15% or less.

Negative-electrode active material for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery

There is provided a negative electrode active material for a nonaqueous electrolyte secondary battery, the negative electrode active material including a base particle containing Si and SiO, a mixed phase coating that covers a surface of the base particle and contains SiOand carbon, and a carbon coating that covers a surface of the mixed phase coating. The base particle is preferably formed of SiO(0.5&#x2264;X&#x2264;1.5). The mixed phase coating preferably contains carbon dispersed in a phase formed of SiO. The cycle characteristics of a nonaqueous electrolyte secondary battery including negative electrode active material particles containing Si and SiOare improved.

Negative electrode active material for nonaqueous electrolyte secondary battery

Provided are a positive electrode active material capable of suppressing the reduction in capacity of a battery and the generation of gas during storage at high temperature in a charged state and a nonaqueous electrolyte secondary battery including the positive electrode active material. A positive electrode active material particle () includes a lithium transition metal oxide particle () containing a halogen atom and rare-earth compound particles () attached to the surface of the lithium transition metal oxide particle (). The amount of the halogen atom present on the surface of the lithium transition metal oxide particle () is 5 mass percent or less of the total amount of the halogen atom contained in the lithium transition metal oxide particle (). A rare-earth element making up the rare-earth compound particles () is one other than yttrium and scandium.

Positive electrode active material and nonaqueous electrolyte secondary battery

The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle () according to an embodiment includes a lithium silicate phase () represented by LiSiO{0&#x3c;z&#x3c;2} and silicon particles () dispersed in the lithium silicate phase (). The silicon particles () have a crystallite size of 40 nm or less. The crystallite size is calculated using the Scherrer equation from the half-width of the diffraction peak of the Si (111) plane in an XRD pattern obtained by XRD measurement of the negative-electrode active material particle

The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle () according to an embodiment contains a base particle (), which includes a lithium silicate phase () represented by LiSiO{0&#x3c;z&#x3c;2} and silicon particles () dispersed in the lithium silicate phase (). The symmetry determined by an image analysis of a backscattered electron image of a cross section of the base particle () is 1.5 or less. The symmetry refers to the ratio (b/a) of the half width at half maximum b of a peak on the high-gray-scale side to the half width at half maximum a of the peak on the low-gray-scale side in a histogram of color distinction based on 256 gray levels for each pixel of the backscattered electron image.

A negative electrode for nonaqueous electrolyte secondary batteries is provided which includes SiOand allows the cycle characteristics of batteries to be enhanced. A negative electrode according to an example embodiment includes a negative electrode current collector and a negative electrode mixture layer disposed on the current collector. The negative electrode mixture layer includes SiO(0.5&#x2264;x&#x2264;1.5) particles having a carbon coating on a particle surface, carbonaceous active material particles, and a compound having at least one of a carboxyl group and a hydroxyl group and having an average number of etherifying agent moieties present per unit molecule of not more than 0.8. The carbon coating includes a first coating disposed on the surface of the SiOand a second coating disposed on the first coating and including carbon having higher crystallinity than the carbon forming the first coating.

Negative electrode including SiOx particles having carbon coating, carbonaceous active material particles, and compound having carboxyl or hydroxyl group and nonaqueous electrolyte secondary batteries

In a nonaqueous electrolyte secondary battery containing SiOas a negative electrode active material, initial charge/discharge efficiency and cycle characteristics are increased. A negative electrode active material for nonaqueous electrolyte secondary batteries is provided. The negative electrode active material contains particles comprising of SiOx (0.8&#x2264;X&#x2264;1.2). The particles have cracks therein. SiOpreferably contains a lithium silicate phase, a Si-M compound, or an oxide of M (M is at least one selected from the group consisting of Al, Ti, Fe, and Ni). The cracks preferably extend radially from inner portions of the particles.

Negative electrode active material for nonaqueous electrolyte secondary batteries and nonaqueous electrolyte secondary battery containing negative electrode active material

The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle () according to an embodiment includes a lithium silicate phase () represented by LiSiO{0&#x3c;z&#x3c;2} and silicon particles () dispersed in the lithium silicate phase (). A lithium silicate constituting the lithium silicate phase has a crystallite size of 40 nm or less. The crystallite size is calculated using the Scherrer equation from the half-width of a diffraction peak of a (111) plane of the lithium silicate in an XRD pattern obtained by XRD measurement of the negative-electrode active material particle

Negative-electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

A negative-electrode active material for a non-aqueous electrolyte secondary battery containing a silicon material, wherein the negative-electrode active material can constitute a non-aqueous electrolyte secondary battery having high charge capacity, high initial charge/discharge efficiency, and good cycle characteristics. A negative-electrode active material particle according to an embodiment includes a lithium silicate phase represented by LiSiO{0&#x3c;z&#x3c;2} and particles dispersed in the lithium silicate phase. Each of the particles includes a silicon core particle and a surface layer formed of an iron alloy containing Si (FeSi alloy). In an XRD pattern of the negative-electrode active material particle obtained by XRD measurement, a diffraction peak of the FeSi alloy at 2&#x3b8;=approximately 45 degrees has a half-width of 0.40 degrees or more, and a diffraction peak of a Si (111) plane at 2&#x3b8;=approximately 28 degrees has a half-width of 0.40 degrees or more.

The invention provides a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge/discharge cycle characteristics. The nonaqueous electrolyte secondary battery includes a negative electrode including a particulate negative electrode active material (), a positive electrode and a nonaqueous electrolyte. The particulate negative electrode active material () includes a plurality of two-phase regions () in the particle wherein the two-phase regions include a first phase (A) containing silicon and a second phase (B) containing silicon oxide disposed on the periphery of the first phase, the negative electrode active material being such that the ratio of the intensity at 480 cmwavelength to the intensity at 510 cmwavelength in a Raman spectrum obtained by Raman spectroscopy is not more than 0.1 and the ratio of the intensity at 2&#x3b8;=21.6 to the intensity at 2&#x3b8;=28.4 in an X-ray diffraction pattern obtained by X-ray diffractometry is not more than 0.1.

Negative electrode active material for nonaqueous electrolyte secondary batteries and nonaqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material has improved cycle life. A negative-electrode active material particle () according to an embodiment includes a lithium silicate phase () represented by LiSiO{0&#x3c;z&#x3c;2}, silicon particles () dispersed in the lithium silicate phase (), and a metallic compound () (other than lithium compounds and silicon oxides) dispersed in the lithium silicate phase (). The metallic compound () is preferably selected from zirconium oxide, aluminum oxide, zirconium carbide, tungsten carbide, and silicon carbide.

Negative-electrode active material for non-aqueous electrolyte secondary battery, negative electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

A positive electrode for a nonaqueous electrolyte secondary battery that does not undergo a decrease in discharge capacity in low-temperature discharge during charge and discharge after the battery is left standing at high temperature in a charged state, for example. The positive electrode for a nonaqueous electrolyte secondary battery includes a positive electrode active material. The positive electrode active material includes a mixture of lithium nickel cobalt manganate and lithium cobaltate having a compound adhered to part of a surface thereof, the compound containing fluorine and at least one selected from zirconium, magnesium, titanium, aluminum, and a rare earth element; and a ratio of the lithium nickel cobalt manganate relative to a total amount of the positive electrode active material is 1% by mass or more and less than 70% by mass.

Positive electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery that uses the positive electrode

An object is to improve the safety of a non-aqueous electrolyte secondary battery at the time of the internal short circuit. The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The positive electrode includes a current collector and a positive electrode active material layer formed on the current collector. The current collector includes a metal foil having a roughened surface. The negative electrode includes a silicon-containing negative electrode active material. The metal foil is preferably a metal foil containing aluminum. The metal foil preferably has a surface roughness Ra of 0.1 to 2.0 &#x3bc;m.

Growing community of inventors

Tokushima, Japan

Taizou Sunano