Two-dimensional covalent organic frameworks with p- and bipolar-type redox-active centers for organic high-performance Li-ion battery cathodes. Issue 31 (1st August 2022)

• Record Type: Journal Article
• Authors: Gong, Lei; Yang, Xiya; Gao, Ying; Yang, Gengxiang; Yu, Zonghua; Fu, Xianzhang; Wang, Yinhai; Qi, Dongdong; Bian, Yongzhong; Wang, Kang; Jiang, Jianzhuang
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 31(2022)
• Page Start: 16595
• Page End: 16601
• Publication Date: 2022-08-01
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta03579k
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A bipolar-type 2D COF has been fabricated through the condensation of TPPDA and Cu-TFPP. The COF cathode with p- and bipolar-type redox-active centers exhibits good performance for Li-ion batteries. Abstract : Redox-active covalent organic frameworks (COFs) are considered to be promising cathode materials for various secondary batteries. In particular, the combination of building blocks containing p-type/bipolar-type redox-active centers with p-type/bipolar-type linkages into the COF skeleton is supposed to have advantages in outputting a high redox potential with increased capacities and good cycling stability, which, however, has not been reported, to the best of our knowledge. Herein, a bipolar-type 2D COF, namely TPPDA-CuPor-COF, has been fabricated through the condensation of tetraphenyl- p -phenylenediamine (TPPDA) with copper-5, 10, 15, 20-tetrakis(4-formylphenyl)-porphyrin (Cu-TFPP). In TPPDA-CuPor-COF, the TPPDA moieties enable a p-type doping reaction while the Cu-TFPP moieties are able to act as bipolar-type active centers, favorable for a high redox potential and increased content of redox-active groups. Thus, in combination with the unhindered ion/electron diffusion paths caused by its stable and crystalline porous structure, the TPPDA-CoPor-COF cathode gives a high capacity of 142 mA h g −1 with a high average output voltage of 2.7 V vs. Li/Li + at 60 mA g −1, excellent rate performance, and good cycling stability in LIBs, revealing the promising application of TPPDA-CuPor-COF as a cathode material for secondary batteries. In addition, the bipolar redox mechanism for the TPPDA-CuPor-COF cathode has been demonstrated by density functional theory (DFT) calculations and ex situ X-ray photoelectron spectroscopy (XPS) during its electrochemical process.