NiSn/nitrogen-doped graphene composite with chemisorption and electrocatalysis as advanced separator modifying material for lithium sulfur batteries.

Lithium-sulfur batteries have been widely studied because of their advantages of abundant reserves, environmental friendliness, low cost andhighspecific capacity. However, the volume expansionand the low electrical conductivity of sulfur, and the shuttle effect of polysulfides limit their application. Herein,wesynthesizea two-dimensional layered NiSn/nitrogen-doped graphene (NG) composite asseparator modifying material for lithium-sulfur batteries. The NiSnformed by dual metal salts Ni(NO)·6HO and SnCl·2HO can adsorb polysulfide and catalyze its transformation to improve the electrochemical reaction kinetics. Moreover, the layered NG can not only disperse the NiSnparticles, but alsoensure rapid electron transfer. Therefore, the lithium-sulfur battery with the NiSn/NG modified separator shows excellent electrochemical performance. At a current rate of 1 C, the lithium-sulfur battery with the NiSn/NG modified separator can provide a high initial discharge capacity of 1022.1 mAh gand maintain a reversible specific capacity of 758.3 mAh gafter 400 cycles.