First-principles study: Polyethylene glycol as a promising coating material for Li-S batteries

Lithium-sulfur batteries are deemed to be state-of-the-art secondary. However, some challenging issues like the shuttle of polysulfide prevent their commercial applications. Polyethylene glycol (PEG) was designed as the cathode or separator coating material to meet these challenges. Here, the relevant properties of PEG400 are systemically investigated using density functional theory computations. PEG400 has been showed to exhibit moderate binding energy for all the polysulfides except S8 because of chemical interactions. In particular, PEG400 was modified with N, and it was found that the adsorption effects between soluble Li2Sn and N-doped PEG400 were significantly improved.