CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, CATHODE FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY

• Main Authors: ARAI NANA, MAKIDERA MASAMI
• Format: Patent
• Language: English; Japanese
• Published: 20.06.2023
• Subjects: BASIC ELECTRIC ELEMENTS; CHEMISTRY; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; ELECTRICITY; INORGANIC CHEMISTRY; METALLURGY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

To provide a cathode active material for lithium secondary battery capable of obtaining a lithium secondary battery of which the initial discharge capacity is high and the discharge capacity is hardly reduced even if charge/discharge is repeatedly performed.SOLUTION: The present invention relates to a cathode active material for lithium secondary battery containing a plurality of particles each containing a lithium metal composite oxide having a layered structure, wherein the lithium metal composite oxide contains at least Li, Ni, Al and an element M and satisfies conditions (1) and (2). (1) Regarding a ratio R1 of an atom number of Al with respect to a total atom number of Ni, Al and M obtained for each particle by measuring surfaces of the plurality of particles using SEM-EDX, a relative standard deviation of the ratio R1 in the plurality of particles is more than 28.5 and equal to or less than 70. (2) Regarding a ratio R2 of the atom number of Al with respect to the total atom number of Ni, Al and M obtained for each particle by measuring the surfaces of the plurality of particles using the SEM-EDX, a relative standard deviation of the ratio R2 in the plurality of particles is more than 13 and equal to or less than 50.SELECTED DRAWING: None 【課題】初期放電容量が高く、繰り返し充放電を行っても放電容量が低下し難いリチウム二次電池を得ることができるリチウム二次電池用正極活物質の提供。【解決手段】層状構造を有するリチウム金属複合酸化物を含む複数の粒子を含有し、リチウム金属複合酸化物は、少なくともＬｉ、Ｎｉ、Ａｌ及び元素Ｍを含有し、下記（１）及び（２）の条件を満たす、リチウム二次電池用正極活物質。（１）複数の粒子の表面をＳＥＭ－ＥＤＸで測定することで粒子毎に得られる、Ｎｉ、Ａｌ及びＭの総原子数に対するＡｌの原子数の割合Ｒ１について、複数の粒子における割合Ｒ１の相対標準偏差は、２８．５より大きく７０以下である。（２）複数の粒子の断面をＳＥＭ－ＥＤＸで測定することで粒子毎に得られる、Ｎｉ、Ａｌ及びＭの総原子数に対するＡｌの原子数の割合Ｒ２について、複数の粒子における割合Ｒ２の相対標準偏差は、１３より大きく５０以下である。【選択図】なし