Biocompatible rapid few-layers-graphene synthesis in aqueous lignin solutions

Ultrasonic-Assisted Liquid Phase Exfoliation (UALPE) is considered one of the most promising approaches for the scale-up of graphene production. The process is based on the isolation and stabilization of layers of 2D materials, such as graphene: the selection of a proper stabilizing/exfoliating agent is crucial to achieve a stable Few-Layers-Graphene (FLG) dispersion. In the present work we propose the use of alkali lignin (AL) as a polymeric stabilizing agent for the rapid ( ≤3 hours) synthesis of FLG. Sonication time and graphite-to-lignin (Gr/AL) ratios were investigated as the primary operational parameters to identify the optimal working conditions. Spectroscopical characterization of the samples were employed to assess the quality of the synthesized material: the analysis of the Raman and XPS spectra provided insight on the number of layers and the nature of the limited defects introduced with the exfoliation procedure. Low-defectivity FLG was obtained at Gr/AL = 8 and a sonication time of 3 hours. Furthermore, Scan- ning Electron Microscopy and Dynamic Light Scattering were performed to investigate the size of the exfoliated flakes ( ∼400 nm). The procedure proposed represents a rapid route for the synthesis of FLG, which will be further explored for composites in chemiresistive devices

All-Inkjet-Printed Ti3C2 MXene Capacitor for Textile Energy Storage

The emerging wearable electronics integrated into textiles are posing new challenges both in materials and micro-fabrication strategies to produce textile-based energy storage and power source micro-devices. In this regard, inkjet printing (IJP) offers unique features for rapid prototyping for various thin-film (2D) devices. However, all-inkjet-printed capacitors were very rarely reported in the literature. In this work, we formulated a stable Ti3C2 MXene aqueous ink for inkjet printing current-collector-free electrodes on TPU-coated cotton fabric, together with an innovative inkjet-printable and UV-curable solvent-based electrolyte precursor. The electrolyte was inkjet-printed on the electrode’s surface, and after UV polymerization, a thin and soft gel polymer electrolyte (GPE) was obtained, resulting in an all-inkjet-printed symmetrical capacitor (a-IJPSC). The highest ionic conductivity (0.60 mS/cm) was achieved with 10 wt.% of acrylamide content, and the capacitance retention was investigated both at rest (flat) and under bending conditions. The flat a-IJPSC textile-based device showed the areal capacitance of 0.89 mF/cm2 averaged on 2k cycles. Finally, an array of a-IJPSCs were demonstrated to be feasible as both a textile-based energy storage and micro-power source unit able to power a blue LED for several seconds

All-Inkjet-Printed Ti₃C₂ MXene Capacitor for Textile Energy Storage

The emerging wearable electronics integrated into textiles are posing new challenges both in materials and micro-fabrication strategies to produce textile-based energy storage and power source micro-devices. In this regard, inkjet printing (IJP) offers unique features for rapid prototyping for various thin-film (2D) devices. However, all-inkjet-printed capacitors were very rarely reported in the literature. In this work, we formulated a stable Ti3C2 MXene aqueous ink for inkjet printing current-collector-free electrodes on TPU-coated cotton fabric, together with an innovative inkjet-printable and UV-curable solvent-based electrolyte precursor. The electrolyte was inkjet-printed on the electrode’s surface, and after UV polymerization, a thin and soft gel polymer electrolyte (GPE) was obtained, resulting in an all-inkjet-printed symmetrical capacitor (a-IJPSC). The highest ionic conductivity (0.60 mS/cm) was achieved with 10 wt.% of acrylamide content, and the capacitance retention was investigated both at rest (flat) and under bending conditions. The flat a-IJPSC textile-based device showed the areal capacitance of 0.89 mF/cm2 averaged on 2k cycles. Finally, an array of a-IJPSCs were demonstrated to be feasible as both a textile-based energy storage and micro-power source unit able to power a blue LED for several seconds