COF containing π-conjugation and precise nitrogen modified cathode enables high-performance lithium–sulfur battery†

Abstract

The covalent organic framework TPE-TPP-COF, containing π-conjugated aromatic tetraldehydes and nitrogen heteroatoms, was obtained under solvothermal conditions. Modification of the cathode with TPE-TPP-COF improved the performance of LSBs even at high sulfur loading (80%). The TPE-TPP-COF/S battery showed 94.6% of its initial coulombic efficiency after 500 cycles at 1C current density, i.e., a coulombic efficiency attenuation rate per cycle of 0.01%. In addition, the TPE-TPP-COF/S cell was observed to display a high rate performance, with a discharge specific capacity of 517.9 mA h g⁻¹ even at a rate of 2C. These results showed that TPE-TPP-COF, as a new model, can provide a new concept for the study of cathodes and provide inspiration for the further development of high-performance batteries.