A Solar Responsive Battery Based on Charge Separation and Redox Coupled Covalent Organic Framework

摘要

Solar-responsive battery holds great promise in solar-to-electrochemicalenergy storage, but is impeded by the lack of efficient photoelectrochemicalcathodes.Herein, a crystalline mesoporous (≈4.0 nm) covalent organicframework (TA-PT COF) with repeating units consisting of covalently linkedtriphenylamine (TPA) and perylenetetracarboxylic diimide (PTCDI) is presented.The repeating unit functions as both a donor–acceptor pair and adual-redox site to realize a molecule-level coupling of intramolecular chargeseparation (τCS = 136.2 ps, τCR = 949 ps) and reversible redox chemistry(C=O/CO?, TPA/TPA+). Equipped with this photoelectrochemical cathode,a reversible aqueous solar-responsive battery delivered a reliable voltageresponseof 376 mV, an extra round-trip efficiency of 35% and a good lightdurability (500 cycles). A photo-coupled electron/mass transfer mechanismof photoelectrons for Zn2+ storage and holes for OTf? storage is furtherrevealed, shedding light on a new photoelectrochemical cathode designbased on charge separation and redox-coupled COF for efficient solar-responsivebatteries.