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 H3PO4 and elucidate its proton conduction mechanism. Herein, a highly stable covalent triazine frameworks (CTFs) based on H3PO4 is reported. The more pyridinic nitrogen CTFs contain, the higher proton conductivity is. Compared with H3PO4@CTF-L with less pyridinic nitrogen, H3PO4@CTF-H has a higher proton conductivity of 1.6x10(-1) S cm(-1) at 150 degrees 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 NtriazineMIDLINE HORIZONTAL ELLIPSISH+MIDLINE HORIZONTAL ELLIPSISH2PO4- pairs by pyridinic nitrogen of CTFs. The outstanding long-term stability is mainly attributed to the ultra-strong triazine skeleton structure of CTFs.