Synergistic effects of porphyrin-ring catalytic center and metal catalytic site from crosslinked porphyrin-based porous polyimides cathode host for lithium polysulfides conversion in lithium-sulfur batteries

The construction of three-dimensional (3D) microporous structure cathode host material used in lithium sulfur battery perfectly provides the combination advantages of good physical confinement and chemical immobilization to suppress polysulfide shuttling. Hence, the construction of advanced POPs-based sulfur cathode hosts with hierarchical pore channel, high pore volume, strong polar segments, and catalytic sites is significant and necessary. Herein, a series of crosslinked porphyrin-based porous polyimides (CR-Por-PPIs) with hierarchical structures were fabricated from porphyrin-based tetramine (TAPP), alkynyl dianhydride (PEPHQDA) and metal inorganic salt (Cu, Co, Ni, Pb, Zn) via polymerization and 360celcius treatment. Owing to the well-constructed porous skeleton architectures, CR-Por-PPIs provide hierarchical pore channels and sufficient pore cavities for trapping polysulfides and relieving volume expansion, afford considerable heteroatom N species for buffering shuttle behaviors via strong chemisorption interaction, endow porphyrin ring catalytic center and metal catalytic sites for enhancing redox kinetics. Profiting from the synergistic efforts, S/CR-Por-PPIs composites cathodes show improved long-term cycle capabilities and rate properties. Chelated metal (Cu, Co, Zn) S/CR-Por-PPIs have superior cycling stabilities due to the promoted catalytic property by virtue of the co-existence of porphyrin-ring catalytic center and metal catalytic sites. These findings can help to facilitate scalable acquisition of highperformance cathode materials for lihium-sulfur batteries, and promote their commercialization.

Automated summary

The construction of three-dimensional microporous structure cathode host materials for lithium sulfur batteries can effectively suppress polysulfide shuttling, improving the cycling stability and rate performance. By developing a series of crosslinked porphyrin-based porous polyimides with hierarchical structures, the research team has provided a new approach for scalable high-performance cathode materials for lithium-sulfur batteries.