Porphyrinic conjugated microporous polymer anode for Li-ion batteries

Porphyrin-based molecules have attracted considerable interests for using as anodes in Li-ion batteries, because of their large π-conjugated aromatic structures, abundant active sites with multi-electron redox activities, and narrow HOMO–LUMO gaps. Herein, a porphyrinic conjugated microporous polymer was prepared through the Sonogashira-Hagihara cross-coupling reaction of Br-functionalized porphyrinic monomer and alkynyl-based monomer. Due to the existence of abundant active sites, rich porosity, narrow bandgap, and inhibition of dissolution in electrolyte, this porphyrinic porous polymer can be used as anode material for Li-ion batteries, and achieves high specific capacity of 1200 mAh g−1 at 1 A g−1, and capacity retention of 242% after 5000 cycles at 3 A g−1. This excellent performance can bear comparison with that of the state-of-the-art organic anode materials. The ex situ X-ray photoelectron spectroscopy tests reveal all of the porphyrin center, benzene ring and alkynyl parts of the porous polymer can be acted as active sites for Li insertion during the cathodic process.