A Hollow Microtubular Triazine- and Benzobisoxazole-Based Covalent Organic Framework Presenting Sponge-Like Shells That Functions as a High-Performance Supercapacitor

Ahmed F M El-Mahdy; Ying-Hui Hung; Tharwat Hassan Mansoure; Hsiao-Hua Yu; Tao Chen; Shiao-Wei Kuo

doi:10.1002/asia.201900296

A Hollow Microtubular Triazine- and Benzobisoxazole-Based Covalent Organic Framework Presenting Sponge-Like Shells That Functions as a High-Performance Supercapacitor

Chem Asian J. 2019 May 2;14(9):1429-1435. doi: 10.1002/asia.201900296. Epub 2019 Mar 12.

Authors

Ahmed F M El-Mahdy^{1

2}, Ying-Hui Hung¹, Tharwat Hassan Mansoure^{2

3

4

5}, Hsiao-Hua Yu^{3

4

5

6}, Tao Chen⁷, Shiao-Wei Kuo^{1

8}

Affiliations

¹ Department of Materials and Optoelectronic Science, Center of Crystal Research, National Sun Yat-Sen University, Kaohsiung, 80424, Taiwan.
² Chemistry Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
³ Institute of Chemistry, Academic Sinica, 128 Academic Road, Sec. 2, Nankang, Taipei, 11529, Taiwan.
⁴ Nanoscience and Technology Program, Taiwan International Graduate Program, Academic Sinica and National Taiwan University, Taipei, 11529, Taiwan.
⁵ Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan.
⁶ Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu, 30010, Taiwan.
⁷ Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Zhongguan West Road 1219, 315201, Ningbo, China.
⁸ Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, 807, Taiwan.

PMID: 30817093
DOI: 10.1002/asia.201900296

Abstract

In this paper we report the construction of a hollow microtubular triazine- and benzobisoxazole-based covalent organic framework (COF) presenting a sponge-like shell through a template-free [3+2] condensation of the planar molecules 2,4,6-tris(4-formylphenyl)triazine (TPT-3CHO) and 2,5-diaminohydroquinone dihydrochloride (DAHQ-2HCl). The synthesized COF exhibited extremely high crystallinity, a high surface area (ca. 1855 m² g^-1 ), and ultrahigh thermal stability. Interestingly, a time-dependent study of the formation of the hollow microtubular COF having a sponge-like shell revealed a transformation from initial ribbon-like crystallites into a hollow tubular structure, and confirmed that the hollow nature of the synthesized COF was controlled by inside-out Ostwald ripening, while the non-interaction of the crystallites on the outer surface was responsible for the sponge-like surface of the tubules. This COF exhibited significant supercapacitor performance: a high specific capacitance of 256 F g^-1 at a current density of 0.5 A g^-1 , excellent cycling stability (98.8 % capacitance retention over 1850 cycles), and a high energy density of 43 Wh kg^-1 . Such hollow structural COFs with sponge-like shells appear to have great potential for use as high-performance supercapacitors in energy storage applications.

Keywords: benzobisoxazole; covalent organic frameworks; energy storage; supercapacitors; triazines; tubular structures.