A Photoresponsive Battery Based on a Redox‐Coupled Covalent‐Organic‐Framework Hybrid Photoelectrochemical Cathode
Wei Wang, Xiang Zhang, Jing Lin, Lei Zhu, Enbo Zhou, Yangyang Feng, Daqiang Yuan, Yaobing Wang
Abstract
Abstract Photoresponsive batteries promise flexible and low‐cost solar‐to‐electrochemical energy storage (SES), but suffer from a limited SES efficiency due to rapid charge recombination and sluggish redox. Here, we present a porous‐shell/core hybrid of covalent organic framework@carbon nanotube. This hybrid ensures long‐lived separated charges (τ ave =3.0 ns) by an electron transfer relay starting from the donor‐acceptor molecules to the nanoscale heterojunction. These charges are further allowed to drive high‐rate redox of −C=O/−C−O − and −C−N/−C=N + with facile kinetics. Equipped with this photoelectrochemical cathode, a photoresponsive aqueous battery shows a 5‐fold enhancement in SES efficiency (1.1 % at 1 sun) over their counterparts. It is unveiled that the electron relay favors the formation of electron‐enriching −C−O− and hole‐enriching −C=N + groups responsible for photoelectrochemical Zn 2+ and OTf − storage cascade; and further, the general photo coupled ions transfer (PCIT) process is proposed. This work presents an inspiring photoelectrochemical cathode design and theoretical insight for photoresponsive batteries.