POSITIVE ELECTRODE ACTIVE MATERIAL AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

• Main Authors: CHOI MOON HO, YU HYUN JONG, PARK JUNG BAE
• Format: Patent
• Language: English; Japanese
• Published: 25.08.2023
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

To provide a positive electrode active material, capable of preventing deterioration in electrochemical properties and stability thereof.SOLUTION: Provided is a positive electrode active material that is a bimodal-type positive electrode active material including a first lithium composite oxide which is a small particle, and a second lithium composite oxide which is a large particle. When r1 represents a difference (at %) between a content of metal elements contained in a first metal oxide in a first coating layer and a content of metal elements of the same type as the metal elements contained in the first metal oxide, on the surface of the first lithium composite oxide which is not covered with the first coating layer, and r2 represents a difference (at %) between a content of metal elements contained in a second metal oxide in a second coating layer and a content of metal elements of the same type as the metal elements contained in the second metal oxide, on the surface of the second lithium composite oxide which is not covered with the second coating layer, the r1 and the r2 satisfying 0.71<r2/r1.SELECTED DRAWING: Figure 1 【課題】正極活物質の電気化学的特性および安定性等の低下を防止することが可能な正極活物質を提供する。【解決手段】小粒子の第１リチウム複合酸化物および大粒子の第２リチウム複合酸化物を含むバイモーダル（ｂｉｍｏｄａｌ）形態の正極活物質であり、第１コーティング層のうち、第１金属酸化物に含まれる金属元素の含有量と、第１コーティング層で覆われていない第１リチウム複合酸化物の表面のうち、第１金属酸化物に含まれる金属元素と同種の金属元素の含有量との差（ａｔ％）をｒ１といい、第２コーティング層のうち、第２金属酸化物に含まれる金属元素の含有量と、第２コーティング層で覆われていない第２リチウム複合酸化物の表面のうち、第２金属酸化物に含まれる金属元素と同種の金属元素の含有量との差（ａｔ％）をｒ２というとき、前記ｒ１および前記ｒ２は、０．７１＜ｒ２／ｒ１を満たす、正極活物質。【選択図】図１