Cathodic dehalogenation polymerization of 2',3',5',6'-tetrafluoro-4,4''-diiodo-1,1':4',1''-terphenyl on zinc metal surface for anode protection

Fluorine-containing poly(p-phenylene) (CityU-42) films on zinc surfaces were directly synthesized using a cathodic dehalogenation C-C coupling strategy. The as-prepared polymers can effectively protect the zinc substrate in aqueous zinc ion batteries (AZIBs). Because CityU-42 is rich in electronegative fluorine group, it can attract the uniform deposition and rapid diffusion of Zn²⁺ on the surface of the anode. Moreover, a large number of benzene rings provide certain mechanical strength, enabling the protective layer to inhibit the growth of dendrites. As a result, the symmetric Zn||Zn cell used CityU-42@Zn can stably cycle for over 1900 h under 5 mA cm^-2 and 1 mAh cm^-2, while the CityU-42@Zn||V₂O₅ full cells maintain high capacity retention after 800 cycles at 5 A g^-1. The results highlight the potential of synthesizing conjugated polymers using cathodic dehalogenation technology, paving the way for further advancement in the field of energy storage technology.