MoP nanoparticles encapsulated in N-doped carbon nanotubes as sulfur host for advanced lithium-sulfur batteries

Abstract

The low electrical conductivity of sulfur, strong volume expansion, shuttle effect, and sluggish redox reactions in Li-S batteries limit their practical application. MoP nanoparticles encapsulated in nitrogen-doped carbon nanotubes (MoP/NC NTs) were synthesized using MoO 3 nanorods as templates via a polypyrrole coating, heat-carbonization, MoO 3 partial reduction, ammonia washing, and phosphorization. The MoP/NC NTs had a hollow nanostructure with a high specific surface area, which can alleviate the volume expansion of the cathode and the shuttle effect of polysulfides. The encapsulated MoP nanoparticles can anchor the polysulfides and enhance the redox reaction kinetics. Thus, the MoP/NC NTs combined with sulfur (MoP/S/NC NTs) exhibited 440.8 mAh·g −1 over 500 cycles at 1.0 A·g −1 with a decay rate of 0.06% per cycle. The density functional theory calculations and X-ray photoelectron spectroscopy results confirmed that MoP/NC NTs could anchor polysulfides and alleviate the shuttle effect by chemical interactions. This study supplies a novel route to prepare nanoparticle-embedded in N-doped carbon nanotubes for advanced Li-S battery.