Self-supported VN arrays coupled with N-doped carbon nanotubes embedded with Co nanoparticles as a multifunctional sulfur host for lithium-sulfur batteries

Abstract

Rational design and synthesis of advanced sulfur host materials has been regarded as an effective strategy to address the critical challenges of lithium-sulfur (Li-S) batteries including shuttle effect of lithium polysulfides (LiPSs), sluggish reaction kinetics, and huge volume change of sulfur. In this work, we demonstrate the rational construction of a multifunctional sulfur host grown on carbon cloth consisting of self-supported porous VN arrays coupled with MOF-derived N-doped carbon nanotubes embedded with tiny Co nanoparticles (named CC/VN/Co@NCNTs). This unique electrode design possesses a series of advantages such as high electrical conductivity, strong physical/chemical confinement of LiPSs, favorable catalytic activity, fast reaction kinetics, effective volumetric accommodation, good mechanical stability and high sulfur loading. As expected, when evaluated as self-standing and binder-free cathode for Li-S batteries, the CC/VN/Co@NCNTs/S exhibits a high initial discharge capacity of 1130.4 mAh g−1 at 0.1C and maintains 864.1 mAh g−1 after 100 cycles, along with outstanding rate performance (625.3 mAh g−1 at 5C) and superior long-term cycling stability with a low capacity decay rate of 0.063% per cycle at 1C for 500 cycles. Moreover, the CC/VN/Co@NCNTs/S delivers high reversible capacities of 847.6, 668.3, and 581.1 mAh g−1 at 0.1C after 100 cycles at different high sulfur loadings of 2.8, 5.2, and 7.8 mg cm−2, respectively. The present work might provide an effective strategy to directly construct multifunctional sulfur host materials on current collectors for high-performance Li-S batteries.