Ni2P composite ZIF-67 derivatives and carbon nanotubes for high-performance lithium-sulfur batteries

Abstract

Lithium-sulfur batteries have high energy density, low cost, and environmental friendliness. They may become one of the most promising advanced energy storage devices. However, the poor electrical conductivity of elemental sulfur and discharge end-products and the infamous shuttle effect have hindered further development of lithium-sulfur batteries. To address these issues, in this work, we synthesized a unique hollow network structured material (Co-NC@CNTs@Ni2P) as a host material for sulfur by a simple hydrothermal method. Ni2P nanoparticles have a strong ability to trap polysulfides, ZIF-67-derived porous carbon (Co-NC) can confine sulfur in an ordered pore structure to alleviate the volume expansion problem, and the addition of modified CNT improves the poor electrical conductivity of the active material. The results show that the Co-NC@CNT@Ni2P/S composite has a high capacity and good cycle stability and the first discharge capacity at a 0.1 C current density reaches 1420.2 mAh/g.