POSITIVE ELECTRODE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

• Main Authors: AIDA TAIRA, KATO TOSHIHIRO, SUGANUMA SHINSUKE
• Format: Patent
• Language: English; Japanese
• Published: 09.01.2024
• 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 positive electrode active material capable of further improving battery capacity and cycle characteristic. when a secondary battery is constituted.SOLUTION: A positive electrode material for lithium ion secondary battery includes: a lithium transition metal composite oxide particle; a hexagonal crystal structure which is expressed by the general formula B (Li1+uNixMnyCozMtO2 in which -0.05≤u≤0.50, x+y+z+t=1, 0.3≤x≤0.8, 0.05≤y≤0.55, 0≤z≤0.4, 0≤t≤0.1, and M is one or more additive elements selected from the element group consisting of, Nb, Mo, Ta, Zr, W) and which has a layer structure; and secondary particles formed by aggregation of a plurality of primary particles. When the positive electrode active material is observed using a scanning electron microscope, the ratio of the number of agglomerated particles of five or more secondary particles to the number of secondary particles in an observation visual field is 0.7% or less. The amount of excess lithium contained in the positive electrode active material is 0.08 mass% or less.SELECTED DRAWING: Figure 1 【課題】二次電池を構成した場合に、電池容量とサイクル特性をさらに向上することが可能な正極活物質を提供することを目的とする。【解決手段】リチウム遷移金属複合酸化物粒子からなるリチウムイオン二次電池用正極活物質であって、一般式（Ｂ）：Ｌｉ１＋ｕＮｉｘＭｎｙＣｏｚＭｔＯ２（－０．０５≦ｕ≦０．５０、ｘ＋ｙ＋ｚ＋ｔ＝１、０．３≦ｘ≦０．８、０．０５≦ｙ≦０．５５、０≦ｚ≦０．４、０≦ｔ≦０．１、Ｍは、Ｎｂ、Ｍｏ、Ｔａ、Ｚｒ、Ｗから選択される１種以上の添加元素）で表され、層状構造を有する六方晶系の結晶構造を有し、複数の一次粒子が凝集して形成された二次粒子からなる正極活物質であり、前記正極活物質を走査型電子顕微鏡を用いて観察した際に、観察視野内の二次粒子の数に対する、５個以上の二次粒子が凝集した凝集粒子の数の割合が０．７％以下であり、前記正極活物質に含まれる余剰リチウム量が０．０８質量％以下であることを特徴とする。【選択図】図１