CATHODE ACTIVE MATERIAL, CATHODE, AND SECONDARY BATTERY

• Main Author: ENDO KASUAKI
• Format: Patent
• Language: English; Japanese
• Published: 28.06.2023
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

To provide a secondary battery capable of obtaining an excellent cycle characteristic.SOLUTION: A secondary battery comprises: a cathode containing a cathode active material; an anode; and an electrolyte. The cathode active material contains a lithium cobalt composite oxide expressed by a following expression. By performing charging, a dQ/dV curve at a time of charging expressing a correlation relationship between a voltage and a differential value obtained by differentiating a capacity with the voltage can be obtained, and by discharging, a voltage difference is 0.01 V or more and 0.08 V or less when the dQ/dV curve at the time of discharge expressing the correlation relationship between the voltage and the differential value obtained by differentiating the capacity with the voltage can be obtained. Li1+xCo1-yMyO2-z (M is at least one kind of Ni, Mn, Al, Mg, Zr, V, W, Mo, Cr, Bi, Cu, Ti, Si, Fe, P, F, B, La, Ga, and Cl. x, y, and z satisfy a following equation of 0≤x≤0.1, 0≤y≤0.2, and 0≤z≤0.02.).SELECTED DRAWING: Figure 1 【課題】優れたサイクル特性を得ることが可能である二次電池を提供する。【解決手段】正極活物質を含む正極と負極と電解液とを備え、その正極活物質は、下式で表されるリチウムコバルト複合酸化物を含み、充電されることにより、電圧と容量を電圧で微分した微分値との間の相関関係を表す充電時のｄＱ／ｄＶ曲線が得られると共に、放電されることにより、電圧と容量を電圧で微分した微分値との間の相関関係を表す放電時のｄＱ／ｄＶ曲線が得られた際、電圧差が０．０１Ｖ以上０．０８Ｖ以下である。Ｌｉ1+xＣｏ1-yＭyＯ2-z（Ｍは、Ｎｉ、Ｍｎ、Ａｌ、Ｍｇ、Ｚｒ、Ｖ、Ｗ、Ｍｏ、Ｃｒ、Ｂｉ、Ｃｕ、Ｔｉ、Ｓｉ、Ｆｅ、Ｐ、Ｆ、Ｂ、Ｌａ、ＧａおよびＣｌのうちの少なくとも１種である。ｘ、ｙおよびｚは、０≦ｘ≦０．１、０≦ｙ≦０．２および０≦ｚ≦０．０２を満たす。）【選択図】図１