Densely packed carbon nanotube forest on silicon substrate for MEMS supercapacitor applications

Densely packed carbon nanotube (CNT) forest on silicon wafer has been fabricated by combining the process of mechanical press and liquid densification. Advantages from the densely packed CNT forest prototype devices include: (1) 16-fold volume reduction with the same amount of CNT forest as compared to the as-grown CNT forest; (2) preservations of aligned CNT organization and natural contacts to the substrate; (3) improved surface flatness of the CNT films. Possible applications for densely packed CNT forests are in energy storage, sensors and other field and here we demonstrate and characterize CNT forest as electrodes in supercapacitors. Experimental results show this volume densification process has successfully increased the energy density of a prototype supercapacitor by 16 times. The resistance of the CNT electrode has also reduced 25% due to the improved material conductivity. Stable performance has been observed during cyclic charge/discharge tests. As such, the presented method of organized densification in aqueous solution for CNT films provides a unique path for improved performance in MEMS/energy applications.