On-Chip Micro-supercapacitors Based on Nanoporous-Gold/ MnO2 Hybrid Electrodes
MnO2-based pseudocapacitive electrodes have been considered as a promising candidate because of their high theoretical specific capacitance (1,370 F/g), environmentally friendly nature and low cost of raw materials. The main drawback of MnO2 is that the poor conductivity may limit the charge/discharge rate for high-power applications. However, Lang et al. have show that hybrid structures made of nanoporous gold and nanocrystalline MnO2 have enhanced conductivity, resulting in a specific capacitance close to the theoretical value (~1,145 F/g). The nanoporous gold not only plays a role as a double-layer capacitor, but also promotes electron transport through the MnO2 and benefits fast ion diffusion between the MnO2 and the electrolytes. Besides, the excellent mechanical properties enable nanoporous gold to be amenable to micro-fabrication processes. The high specific capacitances and charge/discharge rates offered by such nanoporous gold/MnO2 hybrid structures make them promising candidates as electrodes in micro-supercapacitors.
Herein, we make our efforts in preparing high-performance nanoporous gold/MnO2 hybrid electrodes by electrodepositon method and fabricating micro-supercapacitors in interdigitated planar form. Our electrodeposited nanoporous gold/MnO2hybrid electrodes also have a specific capacitance close to the theoretical value (>1,000 F/g). The preparation and performance of hybrid electrodes and micro-supercapacitors will be presented.
1. Lang, X.Y., et al., . Nature Nanotechnology, 2011. 6(4): p. 232-236.
2. Jin, H.J. and J. Weissmüller, Science, 2011. 332: p. 1179-1182.