Triazine covalent organic framework (COF)/θ-Al₂O₃ composites for supercapacitor application

Currently, the preparation of high-performance electrode materials is urgently needed for supercapacitors. As a new kind of organic porous material, covalent organic frameworks (COFs) with an ordered pore structure, a high specific surface area and designability, have shown great potential application value as electrode materials for supercapacitors. However, their potential application in supercapacitors is limited by the poor conductivity of COFs. Here, we in situ grew the highly crystalline triazine-based covalent organic framework DHTA-COF on a modified θ-Al₂O₃ substrate to obtain the composites Al₂O₃@DHTA-COFs. Some of the obtained Al₂O₃@DHTA-COF composites can maintain some degree of crystallinity, good stability and a vesicular structure. Compared to the precursors θ-Al₂O₃ and DHTA-COF, the 50%Al₂O₃@DHTA-COF composite has superior electrochemical properties as electrode materials for supercapacitors. Under the same conditions, the specific capacitance values of 50%Al₂O₃@DHTA-COF (261.5 F g^-1 at 0.5 A g^-1) are 6.2 and 9.6 times higher than the values of DHTA-COF and θ-Al₂O₃-CHO, respectively. Additionally, the 50%Al₂O₃@DHTA-COF electrode material exhibited long-term cycling stability even after 6000 charge-discharge cycles. The study can provide some reference for the development of COF-based composite materials for energy storage.