| 초록 |
Ni-Co hydroxide/graphene hydrogel nanocomposites are fabricated using a two-step method and further explored as a binder-free electrode for high-performance asymmetric supercapacitor. First, freestanding graphene hydrogel is prepared at low temperature using by reducing agent. Second, Ni-Co hydroxide nanoneedles embedded in graphene hydrogel are synthesized using a simple hydrothermal method. The freestanding property of graphene hydrogel allows it to be used as a binder-free electrode, which can improve the energy density of the asymmetric supercapacitor. The composite shows an excellent capacity of 544 C g-1 at 2 A g-1 in a three-electrode system. Moreover, the binder-free asymmetric supercapacitor achieves excellent performance with an energy density of 32.74 Wh kg-1 at a power density of 320 W kg-1. Therefore, the Ni-Co hydroxide/graphene hydrogel nanocomposites have immense potential as electrochemically active materials for the development of high-performance supercapacitor. |
