Direct Solar‐to‐Electrochemical Energy Storage in a Functionalized Covalent Organic Framework

• Published in: Angewandte Chemie International Edition Vol. 57; no. 39; pp. 12716 - 12720
• Main Authors: Lv, Jiangquan, Tan, Yan‐Xi, Xie, Jiafang, Yang, Rui, Yu, Muxin, Sun, Shanshan, Li, Ming‐De, Yuan, Daqiang, Wang, Yaobing
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 24.09.2018
• Edition: International ed. in English
• Subjects: Batteries; bifunctional groups; Charge transfer; covalent organic frameworks; Electric potential; Electrochemistry; Electrode materials; Energy conversion; Energy conversion efficiency; Energy efficiency; Energy storage; Inspection; intramolecular charge transfer; Nondestructive testing; reversible electrochemical reaction; Solar energy; solar energy storage; Voltage; bifunctional groups; reversible electrochemical reaction; covalent organic frameworks; intramolecular charge transfer; solar energy storage
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201806596

A covalent organic framework integrating naphthalenediimide and triphenylamine units (NT‐COF) is presented. Two‐dimensional porous nanosheets are packed with a high specific surface area of 1276 m2 g−1. Photo/electrochemical measurements reveal the ultrahigh efficient intramolecular charge transfer from the TPA to the NDI and the highly reversible electrochemical reaction in NT‐COF. There is a synergetic effect in NT‐COF between the reversible electrochemical reaction and intramolecular charge transfer with enhanced solar energy efficiency and an accelerated electrochemical reaction. This synergetic mechanism provides the key basis for direct solar‐to‐electrochemical energy conversion/storage. With the NT‐COF as the cathode materials, a solar Li‐ion battery is realized with decreased charge voltage (by 0.5 V), increased discharge voltage (by 0.5 V), and extra 38.7 % battery efficiency. A covalent organic framework functionalized with triphenylamine and naphthalenediimide units was used as a cathode. It could synergize photoinduced charge transfer with reversible electrochemical (de)lithiation processes. This leads to decreased charge voltage (by 0.5 V), increased discharge voltage (by 0.5 V), and an extra 38.7 % battery efficiency under illumination.