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Sustainable carbon sources for green laser-induced graphene
Publication . Claro, Pedro I. C.; Pinheiro, Tomás; Silvestre, Sara L.; Marques, Ana C.; Coelho, João; Marconcini, José M.; Fortunato, Elvira; Luiz, Luiz H.; Martins, Rodrigo; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; AIP - American Institute of Physics
Since the discovery of laser-induced graphene (LIG), significant advances have been made to obtain green LIG (gLIG) from abundant, eco-friendly, natural, and organic renewable bio-based carbon sources. Recently, some sustainable and cost-effective electronic devices have been designed with gLIG, resulting in diverse solutions to the environmental impact caused by electronic waste (e-waste). However, there are still several challenges that must be addressed regarding the widespread market implementation of gLIG-based products, from synthesis to practical applications. In this review, we focus on sustainable precursor sources, their conversion mechanisms, physical and chemical properties and applications, along with the challenges related to its implementation, showing the future opportunities and perspectives related to this promising new material. Various systems based on gLIG for energy storage, electrocatalysis, water treatment, and sensors have been reported in the literature. Additionally, gLIG has been proposed for ink formulation or incorporation into polymer matrices, to further expand its use to non-carbon-based substrates or applications for which pristine LIG cannot be directly used. In this way, it is possible to apply gLIG on diverse substrates, aiming at emerging wearable and edible electronics. Thus, this review will bring an overview of gLIG developments, in accordance with the European Green Deal, the United Nations Sustainable Development Goals and the new era of internet-of-things, which demands cost-effective electronic components based on the principles of energy efficiency and sustainable production methods.
Healable Cellulose Iontronic Hydrogel Stickers for Sustainable Electronics on Paper
Publication . Cunha, Inês; Martins, Jorge; Gaspar, Diana; Bahubalindruni, Pydi Ganga; Fortunato, Elvira; Martins, Rodrigo; Pereira, Luís; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; Wiley
Novel nature-based engineered functional materials combined with sustainable and economically efficient processes are among the great challenges for the future of mankind. In this context, this work presents a new generation of versatile flexible and highly conformable regenerated cellulose hydrogel electrolytes with high ionic conductivity and self-healing ability, capable of being (re)used in electrical and electrochemical devices. They can be provided in the form of stickers and easily applied as gate dielectric onto flexible indium–gallium–zinc oxide transistors, decreasing the manufacturing complexity. Flexible and low-voltage (<2.5 V) circuits can be handwritten on-demand on paper transistors for patterning of conductive/resistive lines. This user-friendly and simplified manufacturing approach holds potential for fast production of low-cost, portable, disposable/recyclable, and low-power ion-controlled electronics on paper, making it attractive for application in sensors and concepts such as the “Internet-on-Things.”.
Carbon-Yarn-Based Supercapacitors with In Situ Regenerated Cellulose Hydrogel for Sustainable Wearable Electronics
Publication . Carvalho, José Tiago; Cunha, Inês; Coelho, João; Fortunato, Elvira; Martins, Rodrigo; Pereira, Luís; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; ACS - American Chemical Society
Developing sustainable options for energy storage in textiles is needed to power future wearable "Internet of Things" (IoT) electronics. This process must consider disruptive alternatives that address questions of sustainability, reuse, repair, or even a second life application. Herein, we pair stretch-broken carbon fiber yarns (SBCFYs), as current collectors, and an in situ regenerated cellulose-based ionic hydrogel (RCIH), as an electrolyte, to fabricate 1D fiber-shaped supercapacitors (FSCs). The areal specific capacitance reaches 433.02 μF·cm-2at 5 μA·cm-2, while the specific energy density is 1.73 × 10-2μWh·cm-2. The maximum achieved specific power density is 5.33 × 10-1mW·cm-2at 1 mA·cm-2. The 1D FSCs possess a long-life cycle and 92% capacitance retention after 10 »000 consecutive voltammetry cycles, higher than similar ones using the reference PVA/H3PO4gel electrolyte. Additionally, the feasibility and reproducibility of the produced devices were demonstrated by connecting three devices in series and parallel, showing a small variation of the current density in flat and bent positions. An environmentally responsible approach was implemented by recovering the active materials from the 1D FSCs and reusing or recycling them without compromising the electrochemical performance, thus ensuring a circular economy path.
UV-cured self-healing gel polymer electrolyte toward safer room temperature lithium metal batteries
Publication . Siccardi, Simone; Amici, Julia; Colombi, Samuele; Carvalho, Jose Tiago; Versaci, Daniele; Quartarone, Eliana; Pereira, Luis; Bella, Federico; Francia, Carlotta; Bodoardo, Silvia; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; International Society of Electrochemistry (ISE) | Elsevier
Solid polymer electrolytes are considered a useful solution for improving the safety of lithium metal batteries. However, these macromolecular systems show low ionic conductivity and suffer from limited cyclability at room temperature. In this work we propose the UV-induced, solvent-free radical copolymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMEM, MW 500) and 2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate (UpyMa) in the presence of poly(ethylene glycol) diacrylate (PEGDA, MW 575), used as crosslinker. The polymers, after activation in small amount of liquid electrolyte, show high thermal resistance, good lithium-ion conductivity and wide electrochemical window. Moreover, thanks to the quadruple hydrogen bond interaction of UpyMa dimer, the polymers show good self-healing properties both at 50 °C and room temperature. Such prepared polymers possess excellent interfacial stability and allow for stable lithium plating and stripping at room temperature. Last but not least, cycling tests against LFP cathode showed a fair and stable discharge capacity at 0.2C with 80% of capacity retention after 300 cycles. Most importantly, after severely mechanically damaging the electrolyte, it showed great recovery of the electrochemical properties, with a restored capacity of 115 mAh g−1 at 0.2C and room temperature. This work highlights a promising strategy for safer room-temperature self-healing quasi solid-state lithium metal batteries.
PRINTED ECO-MATERIALS FOR FLEXIBLE THERMOELECTRIC DEVICES
Publication . Figueira, Joana Roumeliotis Sampaio; Loureiro, Joana; Pereira, Luís
The Internet of Things is already a reality, driving the need for scientists to develop and integrate cost-effective, biocompatible, flexible, and lightweight solutions for universal connectivity, including sensing features. Additionally, sustainability emphasizes the importance of using eco-friendly materi-als and choosing energy-efficient production techniques.
While often promoted as a green energy source, thermoelectric materials excel in temperature-sensitive applications, being capable of detecting thermal stimuli such as human touch. The combina-tion of sustainable Seebeck coefficient holding materials with printing methods enables scalable and affordable thermal sensors that may be flexible, lightweight and biocompatible, opening the door for wearable applications.
This doctoral research focused on the development of printed thermoelectric sensors using graphite-based materials. Sustainability considerations guided the choice of substrates, solvents, and encapsulating materials. The results show that graphite flakes can be used as purchased, yielding pla-nar, vertical, and planar/vertical thermoelectric architectures, capable of containing multiple elements in series, which increases the signal output. The formulated cellulose-based inks can be printed directly onto untreated flexible substrates (paper and fabric). Sensors were also obtained using silicone elas-tomer-based composites, allowing for significant design flexibility and substrate absence. It was possi-ble to achieve touch sensors with fast response times (bellow 1 s) and to have a VON optimization surpassing 4.5 mV (when connecting multiple elements in series, in ~1.5 cm2) and high SNR values (above 300 for EC/GFlakes and up to 170 for PDMS/GFlakes). Regarding the planar sensors made with EC/GFlakes, the printed elements were evaluated and approved for flexible applications, with curvature radii down to 3.5 mm.
At its core, this research addresses the urgent need for versatile and sustainable sensing solu-tions in the era of the 'Internet of Things', showcasing advancements in the field through innovative material applications and low-energy consumption production techniques.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
PTDC/NAN-MAT/32558/2017