Hydrogen Bond Activation by Pyridinic Nitrogen for the High Proton Conductivity of Covalent Triazine Framework Loaded with H3PO4

Under high temperature anhydrous conditions, it is still a formidable challenge to improve the performance of proton-conducting materials based on H3 PO4 and elucidate its proton conduction mechanism. Herein, a highly stable covalent triazine frameworks (CTFs) based on H3 PO4 is reported. The more pyridinic nitrogen CTFs contain, the higher proton conductivity is. Compared with H3 PO4 @CTF-L with less pyridinic nitrogen, H3 PO4 @CTF-H has a higher proton conductivity of 1.6×10-1 S cm-1 at 150 °C under anhydrous conditions, which does not decay after about 18 months exposure in air. The high proton conductivity is associated with the formation and breaking of the activated Ntriazine ⋯H+ ⋯H2 PO4- pairs by pyridinic nitrogen of CTFs. The outstanding long-term stability is mainly attributed to the ultra-strong triazine skeleton structure of CTFs.