Symmetric Supercapacitor Application of Anhydrous Gel Electrolytes Comprising Doped Tetrazole Terminated Flexible Spacers

The current research aimed to produce anhydrous gel organic electrolytes with superior performance for high-temperature supercapacitor applications. Within this scope, anhydrous electrolytes were designed by the termination of 1,4-butanediol diglycidyl ether (BDE] with 5-aminotetrazole (AT). The BDE(AT]₂ was further doped with phosphoric acid (PA] and l-Ethyl-3-methylimidazolium tetra-fluoroborate (EMT, as an ionic liquid] at varied ratios. The structure of fabricated electrolytes was elucidated with various spectroscopic techniques, and thermal studies confirmed high thermal stabilities and low glass transition temperatures, suggesting that they could be used in a wide temperature range. Different supercapacitor systems, in combination with carbon-based electrodes and BDE(AT)₂, BDE(AT)₂-0.1EMT, and BDE(AT)₂-PA-0.1EMT electrolytes, were constructed. The supercapacitor device in combination with BDE(AT)₂-PA-0.1EMT electrolyte, showed the highest ionic conductivity value of 1.2×10⁻⁴ S cm⁻¹. The electrode/electrolyte combination demonstrated a maximum specific capacitance (80.4 F g⁻¹), the highest specific energy (2.91 Wh kg⁻¹), and highly effective electrochemical reversibility (up to 2.250 cycles). The supercapacitor device illustrated a better performance at higher temperatures in terms of its specific capacitance value.[Figure not available: see fulltext.].