Outstanding long-cycling lithium−sulfur batteries by core-shell structure of S@Pt composite with ultrahigh sulfur content

Abstract

Here we proposed a novel approach to greatly enhance the electrochemical performance of Li–S batteries by designing a composite electrode material composed of a core-shell structure of S@Pt composite (sulfur content, 85%) grown on the S surface. The platinum (Pt) nanosheets provide physical barrier and strong chemical binding to anchor LiPSs and improve the electronic conductivity of S. Significantly, by introducing carbon nanofibers (CNFs) as the interlayer, we achieved outstanding Li–S battery with a high initial discharge capacity of 1040 mAh g−1 at 1.0C and a reversible capacity of 742 mAh g−1 after 350 cycles, demonstrating its excellent long-term cycling stability with a low capacity decay rate of 0.08% per cycle. According to the density functional theory (DFT) calculations, we proposed that the superior performance is attributed to the cooperative effects of the strong interfacial interaction between Pt (111) surface and the S8 molecule, and very low reaction energy of decomposition, −6.4 ​eV.

Keywords

• Lithium-sulfur batteries
• Wet chemistry
• High sulfur content
• Pt nanoshell
• Carbon fibers layer