Sumitomo Chemical Company, Limited

Tanaka Chemical Corporation

Kimiyasu Nakao

Kenji Takamori

Hiroyuki Kurita

Daisuke Yamashita

Yuichiro Imanari

Jun-ichi Kageura

Takashi Arimura

Yusuke Maeda

Kyousuke Doumae

Ryota Kobayashi

Takaaki Masukawa

A positive electrode active material for lithium secondary batteries which is able to doped/undoped with lithium ions and contains at least Ni, in which a ratio P/Q (atom %/mass %) of a concentration P (atom %) of sulfur atoms being present in a surface of the positive electrode active material to a concentration Q (mass %) of sulfuric acid radicals being present in the whole positive electrode active material is more than 0.8 and less than 5.0, and the Q (mass %) is 0.01 or more and 2.0 or less.

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

The present invention provides a positive electrode active material for lithium secondary batteries including: secondary particles obtained by aggregating primary particles capable of being doped and de-doped with lithium ions, in which the secondary particles have pores, and pore distribution obtained by a mercury intrusion method satisfies requirements (1) and (2) below:

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

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.

A positive electrode active material, which has a crystallite size &#x3b1;/crystallite size &#x3b2; ratio (&#x3b1;/&#x3b2;) of 1 to 1.75 or less, wherein the crystallite size &#x3b1; is within a peak region of 2&#x3b8;=18.7&#xb1;1&#xb0; and the crystallite size &#x3b2; is within a peak region of 2&#x3b8;=44.6&#xb1;1&#xb0;, each determined by a powder X-ray diffraction measurement using Cu-K&#x3b1; ray, and has a composition represented by formula (I) below:Li[Li(NiCoMnM)]O&#x2003;&#x2003;(I)wherein 0&#x2264;x&#x2264;0.2, 0.3&#x3c;a&#x3c;0.7, 0&#x3c;b&#x3c;0.4, 0&#x3c;c&#x3c;0.4, 0&#x2264;d&#x3c;0.1, a+b+c+d=1, and M is at least one metal selected from the group consisting of Fe, Cr, Ti, Mg, Al and Zr.

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

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Fukui, Japan

Kimiyasu Nakao