Murata Manufacturing Co., Ltd.

Atsushi Ouki

Masaki Kuratsuka

Takashige Fujikawa

Sho Takahashi

Takashi Sato

Tadashi Matsushita

Shinichi Katayama

Takatoshi Munaoka

Ryuji Soeda

Shoichi Nishiyama

Takamasa Ono

Masumi Fukuda

Yosuke Kono

Shinji Hayazaki

Takeo Asanuma

Susumu Endo

Yousuke Shima

Yuya Akiyama

Atsushi Nemoto

Yoshihito Akiyama

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a lithium-nickel composite oxide. The negative electrode includes a lithium-titanium composite oxide. The electrolytic solution includes a carboxylic acid ester. The carboxylic acid ester includes at least one of ethyl acetate, propyl acetate, ethyl propionate, or propyl propionate. A first oxygen spectrum and a second oxygen spectrum are detectable by a surface analysis of the positive electrode by X-ray photoelectron spectroscopy. The first oxygen spectrum has a peak within a range of binding energy that is greater than or equal to 528 eV and less than or equal to 531 eV. The second oxygen spectrum has a peak within a range of binding energy that is greater than 531 eV and less than or equal to 535 eV. A ratio of an intensity of the first oxygen spectrum to an intensity of the second oxygen spectrum is greater than or equal to 0.30 and less than or equal to 0.80. A third oxygen spectrum and a fourth oxygen spectrum are detectable by a surface analysis of the negative electrode by the X-ray photoelectron spectroscopy. The third oxygen spectrum has a peak within a range of binding energy that is greater than or equal to 528 eV and less than or equal to 531 eV. The fourth oxygen spectrum has a peak within a range of binding energy that is greater than 531 eV and less than or equal to 535 eV. A ratio of an intensity of the third oxygen spectrum to an intensity of the fourth oxygen spectrum is greater than or equal to 0.82 and less than or equal to 1.35.

Secondary battery

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes a lithium-nickel composite oxide of a layered rock-salt type.

Positive electrode for secondary battery, and secondary battery

A positive electrode active material for a secondary battery includes a center part and a covering part. The center part includes a layered rock-salt lithium-nickel composite oxide. The covering part covers a surface of the center part and includes a boron compound. The positive electrode active material has a crystallite size of a (104) plane that is greater than or equal to 40.0 nm and less than or equal to 74.5 nm. The crystallite size is calculated by X-ray diffractometry and Scherrer equation. The positive electrode active material has a specific surface area that satisfies a condition represented by −0.0160×Z+1.72≤A≤−0.0324×Z+2.94 where Z is the crystallite size (nm), and A is the specific surface area (m/g). The specific surface area is measured by BET specific surface area measurement method.

Positive electrode active material for secondary battery, and secondary battery

A positive electrode includes first active material particles, second active material particles, and third active material particles, and the second active material particles include an aggregation of second primary particles. The average particle size Dof the first active material particles, the average particle size Dof the second active material particles, and the average particle size Dof the third active material particles satisfy a relationship of D&#x3e;D&#x3e;DA first particle disintegration rate &#x3b1;of the first active material particle and a third particle disintegration rate &#x3b1;of the third active material particle are not more than 20%, and a second particle disintegration rate &#x3b2; of the second active material particle is not less than 70%.

Positive electrode active material, positive electrode, battery, battery pack, electronic device, electric vehicle, power storage device, and power system

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Kyoto, Japan

Atsushi Ouki