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Sustainable functionalized fiber-based structures for application in electronic and electrochemical systems
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Sustainable fiber-based structures for application in electronic and electrochemical systems
Publication . Carvalho, José Tiago Macedo de; Pereira, Luís; Martins, Rodrigo
The main goal of this PhD project was to develop fiber-based energy storage devices, commonly also known as textile-based electrochemical energy storage devices (TEESDs), namely supercapacitors (SCs). By incorporating sustainable processes and materials, two main architectures of fiber-based 1D and 2D, were explored and integrated into textiles.
The developed 1D fiber-shaped supercapacitors (FSCs) combine stretch-broken carbon fiber yarns (SBCFYs) as both current collector and active material, paired with an in-situ regenerated cellu-lose-based ionic hydrogel (RCIHs) as electrolyte. The SBCFYs and cellulose can be recovered for reuse, allowing the fabrication of new 1D FSCs without significant loss in electrochemical performance, even after 2 years and 5 months, owing to the hydrophilic nature of cellulose and stability of the SBCFYs.
The hybridization of SBCFYs was further explored with V2O5, MnO2 and MoS2 as active mate-rials with a particular focus on MoS2. Hydrothermal synthesis using conventional- and microwave-as-sisted heating (CAH, MAH) was conducted. MAH hybridized SBCFYs demonstrate 95.7 % capacitance retention after 3000 cyclic voltammetry (CV) cycles. Moreover, both hybridized SBCFYs displayed capacitive behavior even after 60 days of being synthesized through both approaches.
The 2D architecture was explored by utilizing screen-printing with commercially available inks, including silver, carbon, and PEDOT:PSS, as current collectors and active materials. An impregnated cotton fabric with cornstarch-based electrolyte (CotCSBE) was applied, providing an adhesive and ro-bust interface between the symmetric parts of the device. The influence of the number of PEDOT:PSS printed layers on devices performance was investigated, achieving capacitances of 5.51±0.44 mF·cm-2 at 5 mV·s-1, with 81.93 % retention after 10,000 galvanostatic charge-discharge (GCD) cycles for four layers. The potential of using reduced graphene oxide (rGO) and laser induced graphene (LIG) as both current collectors and active materials in the 2D architecture was also considered.
The fabricated 1D and 2D SCs exhibited versatility on different prototypes. Six woven FSCs connected in series light up three red LEDs. Additionally, five FSCs, hybridized via MAH, connected in series and hand-stitched onto a cotton fabric, demonstrated their ability to power a humidity and temperature sensor for up to 6 minutes. Six printed and textile-based 2D SCs, also connected in series, continually powered a watch for 1 hour.
MoS2 decorated carbon fiber yarn hybrids for the development of freestanding flexible supercapacitors
Publication . Carvalho, José Tiago; Correia, Afonso; Cordeiro, Neusmar J. A.; Coelho, João; Lourenço, Sidney A.; 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; Nature Publishing Group
Academic and industrial efforts have focused on developing energy storage devices for wearable and portable electronics using low-cost, scalable, and sustainable materials and approaches. In this work, commercially available stretch-broken carbon fiber yarns (SBCFYs) were hybridized with mixed phases of 1 T and 2H MoS2 nanosheets via conventional and microwave-assisted heating (CAH, MAH) without the use of binders to fabricate symmetric freestanding 1D fiber-shaped supercapacitors (FSCs). Electrochemical characterization performed in a three-electrode configuration showed promising results with specific capacitance values of 184.41 and 180.02 F·g−1, at 1 mV·s−1 for CAH and MAH, respectively. Furthermore, after performing 3000 CV cycles at 100 mV·s−1, the capacitance retention was 79.5% and 95.7%, respectively. Using these results as a reference, symmetric 1D FSCs were fabricated by pairing hybridized SBCFYs with MoS2 by MAH. The devices exhibited specific capacitances of approximately 58.60 ± 3.06 F·g−1 at 1 mV·s−1 and 54.81 ± 7.34 F·g−1 at 0.2 A·g−1 with the highest power density achieved being 15.17 W·g−1 and energy density of 5.06×10–4Wh·g−1. In addition, five 1D FSCs were hand-stitched and connected in series onto a cotton fabric. These supercapacitors could power a temperature and humidity sensor for up to six minutes, demonstrating the practicality and versatility of the prepared 1D FSCs for powering future electronic systems.
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Fundação para a Ciência e a Tecnologia
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OE
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COVID/BD/153262/2023