Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyota Jidosha Kabushiki Kaisha

Youji Takeuchi

Yoshio Ukyo

Chikaaki Okuda

Tsuyoshi Sasaki

Osamu Hiruta

Yuichi Itou

Hiroki Kondo

Hiroshi Sawada

Akira Tsujiko

Tomitaro Hara

Sachie Yuasa

Mamoru Mizutani

Masao Kohzaki

Takahito Imamine

A lithium-ion secondary battery with excellent durability is provided using a two-phase coexisting compound as a positive electrode active material. This lithium-ion secondary battery is provided with an electrode body having a positive electrode containing a positive electrode active material and a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte solution containing a lithium salt in an organic solvent. The positive electrode active material is mainly composed of a two-phase coexisting compound containing lithium, and also contains particles of a lithium-transition metal oxide with a layered structure. The particles of the layered oxide have an average particle diameter of 2 &#x3bc;m or less, and the percentage content thereof in the positive electrode active material is 5 mass % or less.

Non-aqueous electrolyte solution type lithium ion secondary battery

The present invention provides a water based lithium secondary battery that can inhibit deteriorations in capacity owing to charge-and-discharge operations and maintain a high capacity even after it is charged and discharged repeatedly. The water based lithium secondary battery includes a positive electrode, a negative electrode, a separatorsandwiched between these, and an aqueous electrolyte solution obtained by dissolving an electrolyte made of a lithium salt in a water based solvent. As the water based solvent, a pH buffer solution is employed. The buffer solution is obtained by dissolving an acid and its conjugate base's salt, a base and its conjugate acid's salt, a salt made from a weak acid and a strong base, a salt made from a weak base and a strong acid, or a salt made from a weak acid and a weak base in water.

Water based lithium secondary battery

A carbon-containing lithium-iron composite phosphorus oxide for a lithium secondary battery positive electrode active material, includes particles being composed of a lithium-iron composite phosphorus oxide having an olivine structure whose basic composition is LiFePO, and being composited with carbonaceous fine particles. A process for producing the same includes the steps of mixing a lithium compound making a lithium source, an iron compound making an iron source, a phosphorus-containing ammonium salt making a phosphorus source and carbonaceous fine particles, thereby preparing a mixture, and calcicing the mixture at a temperature of from 600&#xb0; C. or more to 750&#xb0; C. or less.

Carbon-containing lithium-iron composite phosphorus oxide for lithium secondary battery positive electrode active material and process for producing the same

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Seto, Japan

Youji Takeuchi