Low-temperature vapour phase polymerized polypyrrole nanobrushes for supercapacitors
A low-temperature modified vapour-phase synthesis allows for the deposition of high aspect ratio, conductive and capacitive one-dimensional nanostructures of the conducting polymer polypyrrole onto three-dimensional fibrous substrates. Nanofibrillar polypyrrole resembling nanobrushes can be deposited at temperatures as low as 50 °C without the use of hard templates. When deposited on a conductive substrate such as hard carbon paper, the nanofibers exhibit a three-electrode specific capacitance of 144.7 F g−1 over a 1.2 V window in 1 M lithium perchlorate with good reversibility. Two electrode electrochemical capacitors fabricated using polypyrrole on hard carbon paper exhibit a specific energy ranging from 7 to 13 W h kg−1 based on average electrode active mass with a maximum charging voltage between 0.6 and 1 V. Furthermore, the devices can undergo 200000 cycles while retaining 70% of their initial capacitance when charged to 0.6 V. This work represents a significant advance in the synthesis of nanostructured polypyrrole from the vapor phase.