One-pot synthesis of highly conductive nickel-rich phosphide/CNTs hybrid as a polar sulfur host for high-rate and long-cycle Li-S battery

Abstract

Lithium sulfur battery has been identified as a promising candidate for next storage devices attributing to ultrahigh energy density. However, non-conductive nature of sulfur and shuttling effect of soluble lithium polysulfides are intractable remaining problems. Herein, we develop a highly conductive nickel-rich Ni12P5/CNTs hybrid with high specific surface area as sulfur host to address these issues. The polar nature of Ni12P5/CNTs can significantly relieve the shuttle effect by means of a strong affinity towards lithium polysulfides and enhance kinetics of polysulfides redox reactions. In addition, the Ni12P5/CNTs with a superior conductivity (500 S·m−1) and high surface area of 395 m2·g−1 enables the effective electron transfer and expedited interfacial reaction. As a result, Ni12P5/CNTs hosted sulfur cathode exhibits high rate capability (784 mAh·g−1 at 4 C) and stable cycling performance with a negligible capacity fading of 0.057 % per cycle over 1,000 cycles at 0.5 C. This work paves an alternative way for designing high performance sulfur cathodes involved metal-rich phosphides.