| 초록 |
Sodium-ion capacitors (SICs) combined with the high energy of the battery and the high capacity of the capacitor have been investigated for several years. Sodium-based materials are considered as a next-generation electrode material with its abundant resource and relatively low cost. Especially, sodium pre-intercalated layered metal oxides are attractive because of their unique crystal structure, simple synthesis process, and high specific capacity. However, the poor cyclic stability of layered metal oxides has limited their application. In this study, we synthesized Na0.67Ni0.15Mn0.7Cu0.05Mg0.1O2 (NMCM) and modified the surface of NMCM with sodium phosphate (NMCM@P) to improve cyclic stability. The capacity retention after 5000 cycles was 71.3 % compared to 17.6 % of bare Na0.67Ni0.15Mn0.7Cu0.05Mg0.1O2. This system produced an energy density of 54.6 Wh/kg and a specific power of 3000 W/kg. |
