Binder-free textile PAN-based electrodes for aqueous and glycerol-based electrochemical supercapacitors

• Autor(a) principal: Barbosa, Ingrid Ariani Belineli
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/85/85134/tde-06102023-140822/
• topic: choline chloride; cloreto de colina; EDLC; EDLC; fibra PAN têxtil; glicerol; glycerol; supercapacitor; supercapacitores; textile PAN-based fibers

Amidst different types of energy storage devices, electrochemical supercapacitors have received considerable attention as they close the gap between electrolytic capacitors and batteries. This work addresses electric double-layer capacitors (EDLCs), a type of electrochemical supercapacitor, and has been divided into two parts. In the former, the production and characterization of activated carbon fiber-felt (ACFF) electrodes derived from textile PAN-based fiber have been provided. In the latter, the electrochemical characterization of EDLCs in aqueous electrolytes (acidic and alkaline) and in three types of glycerol-based electrolytes have been investigated. Binder-free ACFF electrodes have a high specific surface area of 1875 m2 g-1, containing 87% of the total volume of pores as micropores (maximum pore width of 3 nm), and a modal distribution of 1.2 nm. Electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge techniques were carried out in a symmetric two-electrode setup at room temperature. The results showed that ACFF electrodes are suitable for acidic and alkaline aqueous electrolytes as well as the choline chloride-glycerol hybrid electrolyte (ChCl:GLY) at a molar ratio of 3:1. Among aqueous electrolytes, H2SO4 2 mol L-1 had the most satisfactory electrochemical performance in terms of power and energy, followed by KOH 2 mol L-1 and H2SO4 1 mol L-1. Among the glycerol-based electrolytes investigated in this work, ChCl:GLY (3:1) has the most comparable performance to aqueous electrolytes. Although power density is still limited due to high internal resistance, ChCl:GLY (3:1) is heat-resistant and a promising alternative electrolyte for supercapacitors applications, especially given that glycerol is a by-product of FAME (fatty acid methyl ester) biodiesel.