Interlayer\nHydrogen-Bonded Covalent Organic Frameworks\nas High-Performance Supercapacitors

Abstract

Covalent\norganic frameworks (COFs) have emerged as promising electrode materials\nin supercapacitors\n(SCs). However, their insoluble powder-like nature, poor capacitive\nperformance in pristine form, integrated with inferior electrochemical\nstability is a primary concern for their long-term use in electrochemical\ndevices. Keeping this in perspective, herein we report a redox active\nand hydrogen bonded COF with ultrahigh stability in conc. H₂SO₄ (18 M), conc. HCl (12 M) and NaOH (9 M). The as-synthesized\nCOF fabricated as thin sheets were efficiently employed as a free-standing\nsupercapacitor electrode material using 3 M aq. H₂SO₄ as an electrolyte. Moreover, the pristine COF sheet showcased\noutstanding areal capacitance 1600 mF cm^–2 (gravimetric\n169 F g^–1) and excellent cyclic stability (>100 000)\nwithout compromising its capacitive performance or Coulombic efficiency.\nMoreover, as a proof-of-concept, a solid-state supercapacitor device\nwas also assembled and subsequently tested.