"All in One" Strategy for Achieving Superprotonic Conductivity by Incorporating Strong Acids into a Robust Imidazole-Linked Covalent Organic Framework.
Tian-Xiang LuanPengtu ZhangQiurong WangXin XiaoYijing FengShiling YuanPei-Zhou LiQiang XuPublished in: Nano letters (2024)
The fabrication of solid-state proton-conducting electrolytes possessing both high performance and long-life reusability is significant but challenging. An "all-in-one" composite, H 3 PO 4 @PyTFB-1-SO 3 H , including imidazole, sulfonic acid, and phosphoric acid, which are essential for proton conduction, was successfully prepared by chemical post-modification and physical loading in the rationally pre-synthesized imidazole-based nanoporous covalent organic framework (COF), PyTFB-1 . The resultant H 3 PO 4 @PyTFB-1-SO 3 H exhibits superhigh proton conductivity with its value even highly up to 1.15 × 10 -1 S cm -1 at 353 K and 98% relative humidity (RH), making it one of the highest COF-based composites reported so far under the same conditions. Experimental studies and theoretical calculations further confirmed that the imidazole and sulfonic acid groups have strong interactions with the H 3 PO 4 molecules and the synergistic effect of these three groups dramatically improves the proton conductivity properties of H 3 PO 4 @PyTFB-1-SO 3 H . This work demonstrated that by aggregating multiple proton carriers into one composite, effective proton-conducting electrolyte can be feasibly achieved.