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.

中文翻译：

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空心微管基于三嗪和苯并二恶唑的共价有机框架，具有海绵状外壳，可充当高性能超级电容器

在本文中，我们报告了基于空心微管三嗪和苯并二恶唑的共价有机骨架（COF）的构建，该骨架通过平面模板2,4,6-的无模板[3 + 2]缩合呈现出海绵状壳。三（4-甲酰基苯基）三嗪（TPT-3CHO）和2,5-二氨基对苯二酚二盐酸盐（DAHQ-2HCl）。合成的COF表现出极高的结晶度，高表面积（约1855 m ²  g ^-1）和超高的热稳定性。有趣的是，对具有海绵状壳的中空微管COF的形成进行了时间依赖性研究，揭示了从最初的带状微晶向中空管状结构的转变，并证实了合成COF的中空性质是受内部控制的。奥斯特瓦尔德熟化，而微晶在外表面的不相互作用是造成肾小管海绵状表面的原因。该COF表现出显着的超级电容器性能：在0.5 A g ^-1的电流密度下具有256 F g ^-1的高比电容，出色的循环稳定性（在1850个循环中保持98.8％的电容）以及43 Wh kg的高能量密度^-1。这种具有海绵状外壳的中空结构COF似乎具有巨大的潜力，可以用作储能应用中的高性能超级电容器。