3D printing supports on-demand manufacturing and the design of both small and large devices. Owing to the range of functional materials that can be used as inks it has diverse application potential. A research group led by Professor Itaru Honma of the Tohoku University Institute of Multidisciplinary Research for Advanced Materials has developed a novel ink by mixing an ionic liquid comprising conductive protons (i.e., hydrogen ions), inorganic nanoparticles, and photo-curing resin, which is burn resistant and exhibits excellent safety properties. Additionally, the team succeeded in developing a conductive proton film (an insulator that conducts protons, which can be used as an electrolyte for batteries and capacitors) that can be applied not only to 3D printing but also to solid-state power storage devices.

In this study, the researchers focused on the mechanism by which the viscosity of ionic liquids changes to form a gel upon mixing with inorganic nanoparticles. Utilizing the fact that the photocurable resin solidifies when the ejected ink is irradiated with an ultraviolet lamp, and so provides a fixed shape, the conductive proton films were also used as the basis for a pseudo-solid electrochemical capacitor. The results suggest that combining ionic liquids with inorganic nanoparticles to form materials may provide a new and fruitful pathway for developing novel technologies for manufacturing wearable and flexible devices.

Development of a conductive proton ink compatible with 3D printing.