Four types of orthorhombic olivine LiMPO4 (M:Co, Fe, Ni and Mn) were investigated as high-voltage cathode active materials for lithium secondary batteries. LiCoPO4 exhibited the highest 4.8 V discharge plateau of 100 mAh/g versus Li/Li+ after initial charging to 5.1 V and its energy density was comparable to that of layered rocksalt LiCoO2 (120 mAh/g × 4 V = 480 mWh/g). In contrast, the open circuit voltage profile of LiFePO4 was 160 mAh/g on the 3 V plateau. The Co2+ state in LiCoPO4 was confirmed using HRXRF.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering