Interlayer hydrogen-bonded covalent organic frameworks as high-performance supercapacitors

Covalent organic frameworks (COFs) have emerged as promising electrode materials in supercapacitors (SCs). However, their insoluble powder like nature, poor capacitive performance in pristine form, integrated with inferior electrochemical stability is a primary concern for their long-term use in electrochemical-devices. Keeping this in perspective, herein, we report a redox active and hydrogen bonded COF with ultrahigh stability in conc. H2SO4 (18 M), conc. HCl (12 M) and NaOH (9 M). The as-synthesized COF fabricated as thin sheets were efficiently employed as a free-standing supercapacitor electrode material using 3 M aq. H2SO4 as an electrolyte. Moreover, the pristine COF sheet showcased outstanding areal capacitance 1600 mFcm-2 (gravimetric 169 Fg-1) and excellent cyclic stability (> 1,00,000) without compromising its capacitive performance or coulombic efficiency. Moreover, as a proof-of-concept, a solidstate supercapacitor device was also assembled and subsequently tested