The synergistic adsorption-electrocatalysis research of Mn2P interlayer for durable large-capacity and high-energy-efficiency Li-S batteries

The commercialization of Li-S batteries (LSBs) as next-generation high-energy-density energy storage devices is hindered by the remarkable shuttle effect of soluble lithium polysulfides (LiPSs). In this study, Mn2P-based materials (Mn2P@C) were investigated as an interlayer between S-contained cathode and separator to confine S species in the cathode region. Specifically, the porous structure of amorphous carbon layer has a physical adsorption effect on LiPSs, while Mn2P not only exhibits a strong chemical bonding force with LiPSs but also helps enhance the solid-liquid phase conversion and Li2S nucleation growth kinetics. Benefiting from the desirable modulation of Mn2P@C, the LSBs have good cycling stability (0.04% capacity decay per cycle), favorable rate capability (659.7 mAh g-1 at 5C), and high energy efficiency (81.4% at 5C). The LSBs still show a specific capacity of 490 mAh g-1 even with a high S loading (8.6 mg cm-2) and lean electrolyte (E/S = 6.2 mu L mg-1). Furthermore, the LSBs with Mn2P@C exhibited high resistance to self-discharge. This study shows Mn2P@C's great potential in the field of LSBs with high energy density and efficiency and provides some insights into commercial design and other relevant fields.