摘要
Recently, the awareness of energy crisis and environmental protection have remarkably increased. In this regard, supercapacitors have attracted significant attention due to their high-power performance and long cycle life. Herein, we propose the design and fabrication of a supercapacitor which possesses a hierarchical structure constructed by reduced graphene oxide (rGO) and oyster shell powder (OSP). The presence of OSP can prevent re-stacking of rGO during hydrothermal, as a result, build the basis of hierarchical structure for Fe 2 O 3 deposition. Depending on the amount of OSP, the Fe 2 O 3 nanoparticles with different morphologies of small particle, rod, needle, and large particle can be obtained via the hydrothermal process. Because of the synergistic effects contributed by rGO, OSPs, and Fe 2 O 3 , the as-synthesized rGO/Oyster/Fe 2 O 3 composite electrode exhibits an excellent specific capacitances of 473.9 F g −1 and 214.1 F g −1 at the scanning rates of 5 and 100 mV s −1 , respectively. Furthermore, an aqueous asymmetric supercapacitor, having the structure of rGO/Oyster/Fe 2 O 3 /Na 2 SO 3 //AC-MnO 2 /Na 2 SO 4 , shows a high operating voltage of 2.2 V, and performs a high energy density of 31.2 W h kg −1 at a power density of 2200 W kg −1 .