| 초록 |
Graphene, a monolayer of sp2 hybridized carbon atoms with intriguing properties including a large theoretical specific surface area (2675 m2 g-1), lightweight, high electrical conductivity, mechanical strength, good chemical and thermal stability, has been investigated for a long time as a potential candidate for boosting energy storage devices. So far, an enormous amount of research on graphene-based supercapacitors has been conducted to achieve high performance supercapacitors, including corrugated graphene, curved graphene, graphene fiber, laser-scribed graphene, and crumpled graphene balls. However, most of the current state-of-the-art graphene-based supercapacitors exhibit poor capacitance (100-200 F g-1) below the theoretical gravimetric capacitance (550 F g-1) as a result of insufficient accessible surface area, poor conductivity and low ion diffusion rate. These critical problems have been surmounted by modifying the structure and morphology of graphene-derived materials. One of the possible strategies is the substitution of carbon with p-element heteroatoms (N, S, P and F) in the graphitic lattice to improve the capacitive performance of supercapacitors. Among them, the nitrogen and sulfur co-doped graphene are some of the most promising candidates for electrochemical energy storage devices such as Li-ion battery, supercapacitors, and catalysts for oxygen evolution reactions. We have demonstrated an effective strategy for designing high-performance binder-free supercapacitors based on three-dimensional nitrogen and sulfur co-doped hole-defect graphene hydrogel. Interestingly, both the specific surface area and the electrical conductivity are strongly dependent on the level of N-and S-doping, which is controlled by introducing a hole-defect and results in efficient modulation of the electrochemical behavior of the Nitrogen and Sulfur Co-Doped Graphene Hydrogel. |
