Construction of symmetric supercapacitors using anhydrous electrolytes containing heterocyclic oligomeric structures

Abstract

Summary The anhydrous electrolytes have become an important part of supercapacitors, which provide temperature‐tolerant applications in various electronic devices. This work reports on the fabrication of a wide‐temperature‐range supercapacitor using 3‐amino‐1H‐1,2,4‐triazole (Atri)/1,4‐butanediol diglycidyl ether (BG) and imidazole (Imi)/BG–based electrolytes in active carbon‐based electrodes. The triazole‐terminated BG (BG(Atri)2) and Imi‐terminated BG (BG(Imi)2) were initially synthesized, and then anhydrous electrolytes were produced by doping BG(Atri)2 and BG(Imi)2 with phosphoric acid (H3PO4) and ionic liquid (IL) at different molar fractions. The supercapacitors constructed with the anhydrous BG(Atri)2/H3PO4/0.1IL and BG(Imi)2/H3PO4/0.1IL electrolytes provided maximum specific capacitances (Cs) of 114 and 191 F g−1 at 1 A g−1, respectively. The corresponding electrolytes yielded the highest energy densities of 15.8 and 26.7 Wh kg−1 at the power densities of 1150 and 1225 W kg−1, respectively. The Imi‐terminated electrolyte‐based supercapacitor indicated superior performance and efficiency even after 2300 charge‐discharge cycles by holding 20% of its original capacitance. The temperature dependence of the supercapacitors' capacitances was studied, and they increased from 191 to 266 F g−1 for BG(Imi)2/H3PO4/0.1IL and from 114 to 148 F g−1 for BG(Tri)2/H3PO4/0.1IL as the temperature increased from 25°C to 75°C.

Highly Flexible and Tailorable Cobalt‐Doped Cross‐Linked Polyacrylamide‐Based Electrolytes for Use in High‐Performance Supercapacitors

“…Moreover, the addition of H 3 PO 4 leads to a strong band located near 950 cm −1 due to the P−OH stretching of H 3 PO 4 . The hydrogen bond network formation over functional units such as O−H⋅⋅⋅O−C and O−H⋅⋅⋅N is the necessity for proton conduction which was denoted by band broadening within 3500–2000 cm −1 [42] . Besides, XRD analysis is provided in Figure S1 to understand the complex formation occuring after cobalt doping.…”