| 초록 |
Layered lithium nickel-rich oxides, Li[Ni1-xMx]O2 (M = metal), have attracted significant interest as the cathode material for rechargeable lithium batteries due to their high capacity, excellent rate capability, and low cost. However, their low thermal-abuse tolerance and poor cycle life, especially at elevated temperature, prohibit their use in practical batteries. Here, we report on a new concentration-gradient cathode material for rechargeable lithium batteries based on a layered lithium nickel cobalt manganese oxide. In this material, each particle has a central bulk that is rich in nickel and a manganese-rich outer layer with decreasing Ni concentration and increasing Mn and Co concentrations as the surface is approached. The former provides high capacity, while the latter improves the thermal stability. Our concentration-gradient material also showed superior performance in thermal-abuse tests compared with the bulk composition Li[Ni0.8Co0.1Mn0.1]O2 used as reference. |
