Two-Dimensional Material Inks for the In-Space Manufacturing of Advanced Sensors and Energy Storage

The ability to manufacture custom or replacement sensors, components, circuits, and systems using materials and resources available in space will significantly reduce resupply mission costs. However, the development of new and more multifunctional inks for various printing modalities has, in the past few years, boosted interest in advanced device manufacturing. Colloidal nanoparticles have attracted extensive attention because of their unique and distinct properties compared to their bulk counterparts. These nanoparticles serve as compelling foundational components for a wide range of technologies, including energy conversion and storage, sensing, and electronics, among others. Here, we highlight our recent investigations into the use of nanomaterial inks for additive manufacturing of electronic devices with energy harvesting and energy storage applications. First, we demonstrate the scalable synthesis of stable gold nanoparticle inks with low-temperature sintering using simple chemical washing steps. Multi-printer compatible aqueous nanomaterial inks were formulated with standardization of nanomaterial inks achieving resistivity as low as ~10^-6 Ω-m for 400 nm thick films sintered at 250°C. Second, we demonstrate the use of plasma-jet printing (PJP), a gravity-independent, electromagnetic field-assisted printing technology, to deposit colloidal thermoelectric nanoflakes with engineered nanopores onto flexible substrates at room temperature. Our printed films demonstrate an electrical conductivity of 2.5× 10³ S/m and a power factor of 70 µW m^-1 K^-2 at room temperature. Finally, we show synthesis and formulation of Ti3C2Tx MXene ink compatible with aerosol jet printing. The developed ink exhibits consistent printing behaviour with minimal overspray and coffee ring issues on Kapton substrates. Electrochemical studies showed that MXene based printed supercapacitors have an areal capacitance of 26.4 mF/cm^-2 at the scan rate of 5 mV s^-1 in an organic-based electrolyte. Our results provide new perspectives on structure-property-processing correlations in printed 2D nanomaterial devices, with broader implications for reliability of printed and flexible electronics for on demand manufacturing of electronics in space environments.