Synthesis of porous N deficient graphitic carbon nitride and utilization in lithium-sulfur battery

• The porous structured N deficient g-C 3 N 4 (NDCN) material was fabricated through a facile polycondensation method. • Stronger interaction between lithium polysulfide and NDCN was demonstrated. • Excellent electrochemical properties were observed for the lithium sulfur battery. Lithium-sulfur battery (LSB) is a very promising candidate in the next generation battery systems due to its high specific capacity (1675 mA h g −1 ) and low cost. Novel host materials, which are designated to suppress the dissolution of lithium polysulfides (LiPS) into electrolyte, play critical roles to solve the long-term cycling problem in LSB. Herein, the porous structured N deficient g-C 3 N 4 (NDCN) material is developed to construct advanced cathode in LSB through a simple fabrication strategy. The obtained NDCN exhibits a unique 3D architecture with abundant macro- and meso -pores to host S and facilitate ion transport, while the abundant active sites provide strong adsorption towards LiPS. As a result of these above merits, LSB based on S@NDCN cathode delivers an excellent long-term cycling stability with a decay rate of 0.045% per cycle over 300 cycles at 1C.