Improving lithium-sulfur battery performances by using conjugative porous polymer as the sulfur support: the case of N-containing porous aromatic framework 41

摘要

N-containing porous aromatic framework 41 (PAF-41) with hierarchical porous structure has been readily synthesized through AlCl3 catalyzed Scholl reaction by using triphenylamine as the monomer. The extended skeleton of PAF-41 is constructed by N-bridged biphenyl groups to generate a consecutive conjugative electronic structure. The hierarchical porous skeleton and the presence of N atoms effectively confine the electroactive species by synergistic physisorption and chemisorption to alleviate the shuttle effect that is induced by the soluble polysulfides. These features render the sulfur impregnated PAF-41 (SPAF-41) improved lithium-sulfur battery performances, especially the cycling stability. SPAF-41 composite cathode with high sulfur loading of 72wt% exhibits enhanced rate capability and excellent cycling performance. The cell delivers a high capacity of 725.8mAhg(-1) at 0.5 degrees C in the first cycle and sustains a reversible capacity of 491.4mAhg(-1) after 500 charge-discharge cycles. A low decay rate of 0.06% per cycle is achieved. The well conductive PAF-41 support bestows the cell high Coulombic efficiency of 97.36%.