All‐Printed Green Micro‐Supercapacitors Based on a Natural‐derived Ionic Liquid for Flexible Transient Electronics

Abstract

The fabrication and characterization of green, flexible, and ultra-thin supercapacitors that are able to operate above 1.5 V is reported, using an all-printed fabrication process. The devices are produced by aqueous spray casting of a natural-derived electrolyte ionogel composed by 2-hydroxyethyl cellulose and by the ionic liquid choline lactate, while the electrodes are composed of highly porous nanostructured carbon films deposited by supersonic cluster beam deposition (SCBD). The obtained supercapacitors (device thickness < 10 μm) are stable to bending and they possess power values up to 120 kW kg -1 . The combination of aqueous spray casting and SCBD constitutes a versatile, scalable, and eco-friendly fabrication process able to directly print interconnected elements suitable for transient electronic systems.

Laser-Induced Graphene Supercapacitors by Direct Laser Writing of Cork Natural Substrates

“…Graphene and graphene-like materials have recently received considerable attention due to their unique properties, which make them particularly suitable for energy storage applications. − In an attempt to make such materials more environmentally sustainable, a number of routes have been proposed for the ecofriendly fabrication of graphene, − graphene nanosheets, graphene quantum dots, graphene oxide (GO), and reduced graphene oxide (rGO). , In parallel, carbon-based natural materials derived from abundant and renewable sources are also increasingly used as electrode materials as their biodegradability and potential cost-effectiveness make them attractive candidates for “green” energy storage applications. − For example, electrodes fabricated from tree bark, wood, coconut leaves, sunflower seed shells, , coconut shells, and pistachio nutshells biomass have already been used in supercapacitor devices with reportedly high specific areal capacitances ( C A ) as high as 311 F g –1 in a KOH electrolyte …”

In Situ Monitoring of Scale Effects on Phase Selection and Plasmonic Shifts during the Growth of AgCu Alloy Nanostructures for Anticounterfeiting Applications

“…The kinetics of the formation of single-component clusters on surfaces and their physical properties has extensively been investigated, both by theory and experiments. ,− Besides such single-component clusters, presently alloys or multicomponent-supported clusters receive increasing attention. Prominent supported cluster synthesis methods include chemical methods and vacuum deposition. − Hence, already much effort has been undertaken to synthesize such multicomponent and metallic clusters using different methods such as pyrolysis, sol–gel synthesis, templating, aggregation sources, , and sputter deposition. ,, The nucleation and growth of silver and copper clusters during magnetron sputtering was observed very successfully by X-ray scattering. , Applications of supported clusters range from heterogeneous catalysis and photocatalysis to information technology and solar cells as well as anticounterfeiting. − Here, nanoscale heterostructures and alloying allow for the facile tuning of chemical and optoelectronic properties. , Sputter deposition allows for alloying and high cluster density layers, enabling, for example, an organic shell-free cluster incorporated in layer-by-layer printing processes …”

Recent Development of Integrated Systems of Microsupercapacitors

“…In addition, exploration of biodegradable and environmentally friendly materials for MSCs is one of the important directions for development of safe and nontoxic micropower supplies in vivo [40][41][42][43][44]. Lee et al [21] successfully prepared a biodegradable MSC by using metal electrodes (e.g., Mo, W, and Fe) on poly(lactic-co-glycolic acid) substrate obtained by electron beam evaporation deposition and NaCl/agarose gel as electrolyte.…”