All-solid-state supercapacitor using a Nafion® polymer membrane and its hybridization with a direct methanol fuel cell

An all-solid-state supercapacitor is fabricated and optimized using a Nafion® membrane and an ionomer. The device shows good capacitance (ca. 200Fg^-1) as demonstrated by cyclic voltammograms (CVs) and charge-discharge curves. The supercapacitor exhibits a relatively stable capacitance during l0,000 cycles of operation. A hybrid system comprising a direct methanol fuel cell (DMFC) and an all-solid-state supercapacitor has been designed and tested. It is confirmed that the power discharged by the supercapacitor is transferred effectively to the DMFC. The power of the hybrid is immediately improved by 30% compared with that of a DMFC alone operating at 25°C. The possibilities of using this system for high energy and high instantaneous power devices and integrated fabrication processes are discussed.