Phosphorus doping of 3D structural MoS2 to promote catalytic activity for lithium-sulfur batteries

To address the issues of "shuttle effect" of soluble polysulfides and sluggish redox kinetics in the cathodes of lithium-sulfur batteries, the acceleration of the polysulfides conversion via electrocatalysis is a promising solution. As a common electrocatalyst, the catalytic ability of two dimensional (2D) MoS2 is considerably diminished due to agglomeration of nanosheets and insufficient active sites. In this work, a phosphorus-doped three dimensional (3D) network of MoS2-based interlayer sandwiched between the S cathode and the separator is developed. The 3D network could prevent 2D nanosheets from stacking and provide fast diffusion channels for Li ions transfer. Phosphorus doped MoS2 forms stronger Mo-S and Li-P bonds to anchor polysulfides and to promote cleavage of S-S or Li-S bonds of lithium polysulfides to accelerate the polysulfides conversion. As a result, the cell exhibits a high specific capacity of 884.4 mAh g−1 after 100 cycles at 0.1C even under the high sulfur loading condition (3.7 mg cm−2). This work may encourage more efforts on heteroatom doping in electrocatalyst to realize a high performance in lithium–sulfur batteries.