Tailoring electrochemical capacitor energy storage using direct write dispenser printing

We present a direct-write, dispenser printing method for additively fabricating solid-state, thick film carbon supercapacitors directly onto any substrate in room temperature, ambient conditions. This proves to be a flexible method for integrating electrochemical energy storage components onto a device and tailoring its performance to a specific application's demands. The capacitors are made using MCMB (mesocarbon microbead) electrode material in a PVDF (polyvinylidene fluoride) gel binder. The gel is able to encapsulate BMIM⁺BF₄^- (l-butyl-3-methylimidazolium tetrafluoroborate) ionic liquid electrolyte, and effectively forms solid-state films. From both galvanostatic and electrochemical impedance measurements, printed capacitors exhibited an average capacitance of 0.50 mF/cm². These tools were also used to evaluate the long-term cycle life of the capacitors, their power and energy density relationship, and compare transport properties.