Sumitomo Chemical Company, Limited

Tanaka Chemical Corporation

Takaaki Masukawa

Yuichiro Imanari

Hiroyuki Kurita

Daisuke Yamashita

Kenji Takamori

Hiroyuki Ito

Yasutaka Iida

Jun-ichi Kageura

Jun-Ichi Kageura

Kimiyasu Nakao

The object of the present invention is to provide a positive electrode active material usable for a lithium ion battery capable of high charge/discharge cycle performance and high discharge capacity. The positive electrode active material for a lithium secondary battery has a layered structure and comprises at least nickel, cobalt and manganese. Further, the positive electrode active material satisfies requirements (1) to (3) below: (1) a primary particle size of 0.1 &#x3bc;m to 1 &#x3bc;m, and a 50% cumulative particle size Dof 1 &#x3bc;m to 10 &#x3bc;m, (2) a ratio (D/D) of volume-based 90% cumulative particle size Dto volume-based 10% cumulative particle size Dof 2 to 6, and (3) a lithium carbonate content in a residual alkali on particle surfaces of 0.1% by mass to 0.8% by mass as measured by neutralization titration.

Positive electrode active material for lithium secondary batteries, positive electrode for lithium secondary batteries, and lithium secondary battery

A positive electrode active material for a lithium secondary cell, having a layered structure and comprising at least nickel, cobalt and manganese, the positive electrode active material satisfying requirements (1), (2) and (3) below: (1) a composition represented by a composition formula: Li[Li(NiCoMnM)]O, wherein 0&#x2264;x&#x2264;0.10, 0.30&#x3c;&#x3b1;&#x2264;0.34, 0.30&#x3c;&#x3b2;&#x2264;0.34, 0.32&#x2264;&#x3b3;&#x3c;0.40, 0&#x2264;&#x3b4;&#x2264;0.10, &#x3b2;&#x3c;&#x3b3;, &#x3b4;+&#x3b1;+&#x3b2;+&#x3b3;=1, M represents at least one metal selected from the group consisting of Fe, Cu, Ti, Mg, Al, W, Zn, Sn, Zr, Ga and V; (2) a secondary particle diameter of 2 &#x3bc;m or more and 10 &#x3bc;m or less; and (3) a maximum peak value in a pore diameter range of 90 nm to 150 nm in a pore diameter distribution determined by mercury porosimetry.

Positive-electrode active material for lithium secondary cell, positive electrode for lithium secondary cell, and lithium secondary cell

Provided is a positive electrode active material which is useful for a lithium secondary battery having a battery resistance lower than that of the conventional positive electrode active material below freezing point. The positive electrode active material for a lithium secondary battery contains at least one element selected from a group consisting of nickel, cobalt and manganese, the positive electrode active material having a layered structure and satisfying all of the following requirements (1) to (3): (1) a primary particle size is 0.1 &#x3bc;m to 1 &#x3bc;m and a secondary particle size is 1 &#x3bc;m to 10 &#x3bc;m; (2) in an X-ray powder diffraction measurement using CuK&#x3b1; radiation, a crystallite size in the peak within 2&#x3b8;=18.7&#xb1;1&#xb0; is 100 &#x212b; to 1200 &#x212b; and a crystallite size in the peak within 2&#x3b8;=44.6&#xb1;1&#xb0; is 100 &#x212b; to 700 &#x212b;; and (3) in a pore distribution obtained by a mercury intrusion method, a pore peak exists in a range where the pore size is 10 nm to 200 nm and a pore volume in the said range is 0.01 cm/g to 0.05 cm/g.

Positive electrode active material for lithium secondary battery, positive electrode, and secondary battery

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Fukui, Japan

Takaaki Masukawa