Self-assembled 3D graphene-based aerogel with Au nanoparticles as high-performance supercapacitor electrode

Construction of porous three-dimensional (3D) heterostructured materials is promising for establishing high-performance energy-storage devices, enabling large surface area, facilitated ion and electron transport, and synergistic effects between multi-components. Here, we report a simple and cost-efficient freeze-casting method to improve the electrochemical performance of porous 3D graphene aerogel (GA) embedded with gold nanoparticles (3D Au/GA). The as-synthesized 3D Au/GA was broadly characterized by XRD, Raman, XPS, SEM, and TEM. Morphology observations show that 3D-porous cellular structure of GA with uniform distribution of 20 nm Au nanoparticles on the surface of GA. Based on structural merits, the electrochemical performance of as-synthesized porous 3D Au/GA was exemplified as electrode materials for supercapacitor with a high specific capacitance of 554 F g(-1) at 5 mVs(-1), excellent cycling stability with capacitance retention of 91.06% after 10,000 cycles, and exhibits significantly specific energy of 10.7 W h kg(-1) at a specific power of 203.5 W kg(-1). This could be ascribed to the synergetic effect of conducting Au and the unique 3D porous, cellular structure of GA. In addition, the developed electrode materials are used to fabricate a symmetric solid-state supercapacitor (SSC) device for demonstrating the practical applicability, and it was able to light a commercial LED. Our method opened a new direction to synthesize porous 3D GA with various nanoparticle decorations for numerous applications as energy storage devices, catalysis, sensors, biomedical, and environmental applications.