Toyota Jidosha Kabushiki Kaisha

Prime Planet Energy & Solutions, Inc.

Shinsuke Matsuhara

Kazuhisa Takeda

Hiroto Asano

Yutaka Oyama

Shuhei Takeshita

Kiyohiko Nakano

Yusuke Araki

Provided is a graphite-based negative electrode active material that can impart both high output characteristics and high cycle characteristics to a nonaqueous electrolyte secondary battery. The graphite-based negative electrode active material disclosed herein is made up of particles having, in a cross-sectional view, a flat central portion made up of graphite, and a porous accumulation portion made up of accumulated graphite, on both sides of the flat central portion. The graphite that makes up the flat central portion is present more densely than the graphite that makes up the porous accumulation portion.

Graphite-based negative electrode active material

The present disclosure provides a negative electrode active material that can realize excellent low temperature characteristics. An negative electrode active material for a lithium ion secondary battery disclosed herein includes a carbon material that is able to reversibly occlude and release lithium ions and a carbon coating layer that is formed on a surface of the carbon material, and the carbon coating layer contains carbon atoms and phosphorus atoms. In addition, in the carbon coating layer, when a peak of a P2p spectrum measured through X-ray photoelectron spectroscopy (XPS) is subjected to waveform separation, it has a peak at a position at which the binding energy is 131 eV.

Negative electrode active material and lithium ion secondary battery including negative electrode active material

A method of producing a lithium ion secondary battery disclosed here, includes a process of preparing an electrode body which includes a positive electrode and a negative electrode and in which the negative electrode contains a negative electrode material containing graphite having open pores and SiOdisposed in the open pores; a process of producing a battery assembly including the electrode body and a non-aqueous electrolytic solution containing LiPFwith a concentration of 1 mol/L or more; a process of initially charging the battery assembly; and a process of performing an aging treatment on the initially charged battery assembly in an environment of a temperature of 50&#xb0; C. or higher.

Method of producing lithium ion secondary battery and negative electrode material

A lithium ion secondary battery includes at least a positive electrode, a negative electrode, and an electrolyte solution. The negative electrode includes a negative electrode current collector and a negative electrode mixture layer. The negative electrode mixture layer is formed on a surface of the negative electrode current collector. The negative electrode mixture layer includes graphite particles, inorganic filler particles, lithium titanate particles, and a water-based binder. The inorganic filler particles have an average primary particle size that is &#xbd; or less of an average primary particle size of the graphite particles. The lithium titanate particles have an average primary particle size of 1 &#x3bc;m or less. A ratio of an average primary particle size of the lithium titanate particles with respect to an average primary particle size of the inorganic filler particles is one or less.

Lithium ion secondary battery and method of producing the same

A negative electrode which includes graphite particles and which is capable of imparting superior input resistance characteristics to a nonaqueous lithium-ion secondary battery is provided. The negative electrode of a nonaqueous lithium-ion secondary battery disclosed herein includes graphite particles as negative electrode active materials and a supported material being supported by the graphite particles. The graphite particles have phenolic hydroxy groups. The supported material has surface hydroxy groups. A ratio of an amount B (mmol/g) of the surface hydroxy groups in the supported material to an amount A (mmol/g) of the phenolic hydroxy groups in the graphite particles is 30 or more and 150 or less.

Negative electrode of nonaqueous lithium-ion secondary battery and nonaqueous lithium-ion secondary battery using same

A nonaqueous electrolyte secondary battery includes a flat wound electrode body that includes a positive electrode sheet, a negative electrode sheet, and a separator sheet, and a nonaqueous electrolyte. The wound electrode body includes a filling layer containing a thermal polymerization product of a resin having electrolyte solution swellability between the negative electrode sheet and the separator sheet.

Nonaqueous electrolyte secondary battery and method of producing the same

A negative electrode material includes at least a graphite particle and a first metal oxide. The graphite particle includes at least one open pore. The graphite particle has a porosity not lower than 13% and not higher than 66%. The first metal oxide adheres to an inner wall of the open pore. The first metal oxide is lithium ion conductive and electron conductive. The first metal oxide is not smaller than 0.5 part by mass and not greater than 20 parts by mass with respect to 100 parts by mass of graphite particle.

Negative electrode material, lithium ion secondary battery, method of manufacturing negative electrode material

According to the present invention, there is provided a negative electrode material for a lithium secondary battery, including a negative electrode active material including a carbon material and having an I/Iratio of XPS of 0.2 to 0.74, and a coating portion disposed on a surface of the negative electrode active material. The coating portion has a boron atom and a crosslinking site having a bonding portion of C&#x2014;O&#x2014;C and interposed between the boron atom and the negative electrode active material. In an XPS spectrum, when an area of the peak of the 1s electron orbital of the boron atom is denoted by Ab and an area of the peak of the C&#x2014;O&#x2014;C bonding portion is denoted by Ac, the ratio Ac/Ab of the peak area Ac to the peak area Ab is 0.11 or more and 0.51 or less.

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Miyoshi, Japan

Shinsuke Matsuhara