Integrating multiple redox-active sites and universal electrode-active features into covalent triazine frameworks for organic alkali metal-ion batteries

The advantages of redox-active polymers with multiple redox-active sites and multiple functions stem from the controllability of organic synthesis, which makes it possible to construct universal organic alkali metal-ion batteries. Herein, triazine-bridged hexaazatrinaphthylene polymer (HATN-CTF) was synthesized and then first served as both cathode and anode materials for lithium organic batteries. Interestingly, we realized the controllable construction of crystalline and amorphous HATN-CTF (cHATN-CTF and aHATN-CTF) and give a systematic study to show the superiority of aHATN-CTF resulted from the more abundant active sites and shortened ion diffusion paths. Most importantly, the integration of hexaazatrinaphthylene core and peripheral triazine moieties endows aHATN-CTF with abundant active centers (C--N and C--C groups), the ability to absorb cations and anions and universal electrode-active features at high/low potential (cathode/anode side), which have been confirmed by the electrochemical analysis, characterizations and theoretical calculations. Further-more, aHATN-CTF also shows potential applications in all-organic symmetric batteries (AOBs), flexible AOBs (FAOBs) and other rechargeable alkali metal-ion batteries. Our findings highlight the importance of redox-active polymers with multiple redox-active sites and multiple electrode-active features and open a new avenue to construct organic alkali metal-ion batteries.

Automated summary

This study successfully constructed universal organic alkali metal-ion batteries by synthesizing redox-active polymers with multiple redox-active sites and multiple functions. The crystalline and amorphous polymers were systematically studied, and it was found that the amorphous polymer with more active sites and shortened ion diffusion paths exhibited superior performance. The integration of different functional groups in the polymer structure enabled it to have abundant active centers, the ability to absorb ions, and universal electrode-active features at high and low potential.