Kabushiki Kaisha Toyota Jidoshokki

Toyota Jidosha Kabushiki Kaisha

National Institute of Advanced Industrial Science and Technology

Tatsuya Eguchi

Manabu Miyoshi

Atsushi Saito

Yuuhi Sato

Jun Kaneda

Masakazu Murase

Tetsuo Sakai

Jun Yoshida

Takahiro Sugioka

Kazuhiro Suzuki

Shinji Nakanishi

Masanori Harata

Daichi Kosaka

Yuta Ikeuchi

Toshikatsu Kojima

Hiroki Oshima

Akira Kojima

Tomokuni Abe

Takeshi Maki

Yusuke Yamamoto

Hitoshi Aikiyo

Provided is a negative electrode active material that contains silicon clathrate II and that is suitable for a negative electrode of a lithium ion secondary battery. The negative electrode active material includes a silicon material in which silicon clathrate II represented by composition formula NaSi(0&#x2264;x&#x2264;10) is contained and a volume of a pore having a diameter of not greater than 100 nm is not less than 0.025 cm/g.

Negative electrode active material containing silicon clathrate II

The negative electrode includes a current collector, a negative electrode active material layer arranged on a surface of the current collector, and a protective layer arranged on a surface of the negative electrode active material layer. The negative electrode active material layer includes a first negative electrode active material having an aspect ratio defined as 'a'/'b' to fall in a range of from two or more to eight or less when a length of the major axis is defined &#x201c;a&#x201d; and a length of the minor axis is defined &#x201c;b.&#x201d; The protective layer includes a ceramic powder.

Negative electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery

A positive electrode for lithium-ion secondary battery includes: a lithium metallic oxide with a lamellar rock-salt structure including nickel, cobalt, and manganese; and a phosphate/carbon composite including an olivine-type phosphate compound at least some of which is coated with carbon partially. A rate of a volume resistivity of the phosphate/carbon composite to a volume resistivity of the lithium metallic oxide is 0.034 or less. The olivine-type phosphate compound is expressed by a general formula: LiMPO(where 'M' is at least one element selected from the group consisting of Mn, Fe, Co, Ni, Cu, Mg, Zn, V, Ca, Sr, Ba, Ti, Al, Si, B, Te and Mo, and 0&#x3c;'h'&#x3c;2). A content of the phosphate/carbon composite is from 15% by mass or more to 35% by mass or less when a summed mass of the lithium metallic oxide and the phosphate/carbon composite is taken as 100% by mass.

Positive electrode for lithium-ion secondary battery, production process for the same, and lithium-ion secondary battery

To provide a lithium ion secondary battery capable of suppressing thermal run-away when internal short circuiting occurs. The lithium ion secondary battery includes: a positive electrode including a current collector, a positive electrode active material layer that is formed on the current collector and that contains a lithium-containing complex oxide having a layered rock salt structure and being represented by general formula: LiNiCoMnDO(0.2&#x2266;a&#x2266;1; b+c+d+e=1; 0&#x2266;e&#x3c;1; D is at least one element selected from Li, Fe, Cr, Cu, Zn, Ca, Mg, S, Si, Na, K, and Al; 1.7&#x2266;f&#x2266;2.1), and a thermal run-away suppressing layer formed on the positive electrode active material layer and containing a lithium transition metal silicate; and a negative electrode including a negative electrode active material. A ratio of the mass of the lithium-containing complex oxide with respect to the mass of the lithium transition metal silicate in the positive electrode is not lower than 1.5.

Lithium ion secondary battery having positive electrode that comprises thermal run-away suppressing layer on positive electrode active material layer

A parameter for producing a positive electrode having excellent safety, and a positive electrode active material layer satisfying the parameter. The positive electrode active material layer includes a first positive electrode active material, a second positive electrode active material having a lower charge/discharge potential than the first positive electrode active material, and an additive. When the first positive electrode active material tap density is defined as dt, the second positive electrode active material tap density is defined as dt, a true density of the additive is defined as d, a mass percentage of the first positive electrode active material is defined as Wt, a mass percentage of the second positive electrode active material is defined as Wt, a mass percentage of the additive is defined as Wt, and a porosity of the positive electrode active material layer is defined as p, the positive electrode active material layer satisfies (1&#x2212;p)&#xd7;(Wt/dt)/((Wt/dt)+(Wt/dt)+(Wt/d))&#x3c;0.38.

Positive electrode active material layer including first positive electrode active material and second positive electrode active material, and method for producing positive electrode including said positive electrode active material layer

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Kariya, Japan

Tatsuya Eguchi