POSITIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY METHOD FOR PREPARING THE SAME AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME

• Main Authors: KIM, HO JUNE, HEO, MIN JI, LEE, JOO SUNG
• Format: Patent
• Language: English; Korean
• Published: 25.01.2019
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

The present invention relates to a positive electrode for a lithium secondary battery, which comprises: a first positive electrode active material including a lithium cobalt-based oxide; and a second positive electrode active material including a lithium composite transition metal oxide including at least two selected from the group consisting of nickel (Ni), cobalt (Co), and manganese (Mn). When a state of charge (SOC) reaching a flat level voltage (CV) during 1C charging of the first positive electrode active material is SOC_1, and the SOC reaching the flat level voltage (CV) during 1C charging of the second positive electrode active material is SOC_2, the relationship between SOC_1 and SOC_2 satisfies the equation 1, SOC_1 < SOC_2 < 1.1 × SOC_1. 본 발명은 리튬 코발트계 산화물을 포함하는 제1 양극 활물질; 및 니켈(Ni), 코발트(Co) 및 망간(Mn)으로 이루어진 군에서 선택된 적어도 2종 이상을 포함하는 리튬 복합 전이금속 산화물을 포함하는 제2 양극 활물질;을 포함하며, 상기 제1 양극 활물질의 1C 충전시 평탄 준위 전압(CV) 도달 SOC(state of charge)를 SOC이라고 하고, 상기 제2 양극 활물질의 1C 충전시 평탄 준위 전압(CV) 도달 SOC(state of charge)를 SOC라고 할 때, 상기 SOC및 SOC의 관계가 하기 식 1을 만족하는 리튬 이차전지용 양극에 관한 것이다. [식 1] SOC< SOC< 1.1×SOC