A conductive sulfur-hosting material involving ultrafine vanadium nitride nanoparticles for high-performance lithium-sulfur battery

A three-dimensional nitrogen doped porous carbon/vanadium nitride nanoparticles (3DNPC/VN) as a sulfur-hosting material for lithium-sulfur battery has been successfully synthesized by a facile method. Within this method, the 3D nanoporous carbonaceous framework is obtained by a one-step carbonization of sodium citrate. The ultrafine VN nanoparticles with typical size of 5-10 nm are prepared by a common condition of 700 degrees C heat-treatment under flowing N-2, and they are uniformly dispersed in the pores of carbon skeleton, as shown in the TEM images. The VN nanoparticles here play important roles of enhancing electronic conductivity, anchoring polysulfides and catalyzing reaction reversion. At a rate of 1C, the 3DNPC/VN-S cathode exhibits a discharge specific capacity of 734 mAh g(-1) for the initial cycle and a reversible capacity of 615 mAh g(-1) after 300 cycles, achieving a high capacity retention rate of 83.8%. Even at a high rate of 8 C, the discharge capacity of the 3DNPC/VN-S cathode can still reach 687 mAh g(-1), indicating an excellent rate performance. Therefore, this novel strategy is effective on designing a high-performance lithium-sulfur battery. (C) 2019 Elsevier Ltd. All rights reserved.