Water-Transferable, Inkjet-Printed Supercapacitors towards Conformed 3-Dimensional and Epidermal Energy Storage

Name of the conference: Materials Research Society (MRS) Conference)

Date of publication: 1- 6 December 2019

Abstract: The rapid development of Internet-of-Things (IoT) requires the use of embedded electronics into physical components and daily objects which stimulates a tremendous and rapidly grown interest for electronic devices and energy storage systems that are flexible, wearable and conformal. Typical fabrication methods, such as photolithography and winding or stacking, that are commonly used in conventional electronics and energy storage systems respectively, are difficult to be applied as fabrication strategies towards devices with advanced form factors (e.g. three-dimensional (3D), stretchable, conformal). In this study, we demonstrate the fabrication of supercapacitors on 3D objects through inkjet and water-transfer printing. To the best of our knowledge, this is the first reported study on water-transfer printing of an active functional device such as energy storage. Planar supercapacitors constituted from nanoparticle-based silver current collector, nanoparticle-based nickel (II) oxide (NiO) active electrode material and an ionic liquid or surfactant-based saturated magnesium perchlorate /ultraviolet-cured triacrylate polymer-based solid-state electrolyte, were chosen as model materials to explore the feasibility of the proposed concept. To further explore the practical potential of the inkjet-printed supercapacitors with a particular focus on wearable applications, we fabricated an epidermal (or tattoo) printable supercapacitor, that was water-transferred on the skin of a human subject, to potentially serve as the power source for wearable health systems. The 3D and epidermal devices showed areal specific capacitances of up to 52 mF·cm-2 and 27 mF·cm-2 respectively. This new class of water transferable, inkjet-printed, all-solid-state supercapacitors with advanced conformality, offer new alternative approach towards monolithically-integrated/object-tailored power sources that are needed for complex-shaped devices for IoT and flexible/wearable electronic applications.