Effects\nof Electrolyte Salts on the Electrochemical\nPerformance of Aromatic Polyaroxydiazole Anodes for Pseudocapacitors

Poly(4,4′-biophenylene-1,3,4-oxadiazole)\n(b-POD) is an n-type\nconductive polymer (CP) with a high specific capacitance and excellent\nrate performance. However, its practical application in pseudocapacitors\nis hindered by severe cycling performance decay. Electrolytes, as\ncrucial components, significantly influence the electrochemical performance\nof pseudocapacitors. Therefore, selecting an appropriate electrolyte\nis essential for improving the cycling stability of b-POD, as thoroughly\ninvestigated in this study. Larger cations with lower surface charge\ndensities require a smaller driving force for injection into the b-POD\nelectrode, resulting in a more positive doping potential. Particularly,\nBu<sub>4</sub>N<sup>+</sup> with a well-delocalized electronic structure\nforms a weaker interaction force with negatively charged polymer polarons,\nfacilitating its dissociation from the polymer polarons, thereby ensuring\ngood reversibility and excellent cycling stability. In the Bu<sub>4</sub>NBF<sub>4</sub> electrolyte, b-POD exhibits a capacitance\nretention of 93.2% after 10 000 cycles, coupled with a Coulombic\nefficiency close to 100%. Furthermore, it demonstrates outstanding\nrate performance, maintaining a specific capacitance of 272 F g<sup>–1</sup> even at 20 A g<sup>–1</sup>, which is 87.2%\nof the specific capacitance tested at 1 A g<sup>–1</sup>. Finally,\na high-performance asymmetric pseudocapacitor with high energy and\npower densities has been fabricated. This study aims to offer insights\ninto the design of next-generation POD-derived pseudocapacitors.