Conformal Polymeric Multilayer Coatings on Sulfur Cathodes via the Layer-by-Layer Deposition for High Capacity Retention in Li–S Batteries

We report on the conformal coating of thickness-tunable multilayers directly onto the sulfur (S 8 ) cathodes by the layer-by-layer (LbL) deposition for the significant improvement in the performances of Li–S batteries even without key additives (LiNO 3 ) in the electrolyte. Poly(ethylene oxide) (PEO)/poly(acrylic acid) (PAA) multilayers on a single poly(allylamine hydrochloride) (PAH)/PAA priming bilayer, deposited on the S 8 cathodes, effectively protected from the polysulfide leakage, while providing a Li + ion diffusion channel. As a result, PAH/PAA/(PEO/PAA) 3 multilayer-coated cathodes exhibited the highest capacity retention (806 mAh g –1 ) after 100 cycles at 0.5 C, as well as the high C-rate capability up to 2.0 C. Furthermore, the multilayer coating effectively mitigated the polysulfide shuttle effect in the absent of LiNO 3 additives in the electrolyte.