LASER INDUCED GRAPHENE MODIFICATION WITH METAL OXIDES FOR HIGH ENERGY DENSITY MICROSUPERCAPACITORS

• Autor(a) principal: Abreu, Rodrigo Miguel Diogo de
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/159104
• topic: LIG-MSC; paper-based devices; MnO2; flexible electronics; manual drop casting; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

Laser-induced graphene (LIG) on paper is a promising material for flexible micro-supercapacitors (MSC) due to its simple and cost-effective processing. However, common production procedures of MSC are restrained to the production of carbon-based electrodes which exhibit relatively low energy densities. Metal oxides exhibit faradaic pseudocapacitance due to reversible redox reactions at the electrode-electrolyte interface resulting in higher energy storage capacity compared to carbon-based electrodes used in electric double-layer capacitors. Manganese oxide (MnO2) exhibits excellent electrochemical stability, its low cost, abundant, and environmentally friendly which contributes to its attractiveness. In this work, an optimized, cost-effective, reproducible, approach is presented for the preparation of manganese oxide decorated LIG-MSC structures via a one-step direct laser writing (DLW) after a manual drop-casting of manganese acetate on chromatography paper. The developed strategy relies on soaking the paper in a 1 M manganese acetate prior to the laser processing. Manganese acetate is converted into MnO2, along with LIG production, which will improve LIG-MSC energy density. A comparison between planar interdigitated and sandwich architectures was conducted to ensure the best performance design. LIG on paper with MnO2 exhibits sheet resistance (53 Ω sq−1 ) and an optimized electrode/electrolyte interface was obtained by the proposed method. When used as a MSC in an planar interdigitated design, this LIG-MSC with manganese oxide resulted in a specific capacitance of 12.30 mF cm−2 (0.05 mA cm−2 ). Furthermore, the devices exhibit excellent cycling stability with 1385.85 μF cm -2 (> 10,000 cycles), good energy density with 0.004 Wh cm -2 (at a power of 0.07 W cm - 2 ). Thus, this work suggests manganese oxide based LIG-MSC can be used as energy storage devices for flexible, low-cost, and portable electronics. Additionally, due to their flexible design and architecture, they can be easily adapted to other circuits and applications with different power requirements.