Ni3Sn2/nitrogen-doped graphene composite with chemisorption and electrocatalysis as advanced separator modifying material for lithium sulfur batteries

We have designed a two-dimensional layered Ni3Sn2/nitrogen-doped graphene composite as separator modifying material for lithium-sulfur batteries. This composite not only has strong chemical adsorption effect on polysulfide, but also promotes the rapid transformation of polysulfide, thus improving the cyclic stability of lithium sulfur batteries. [Display omitted] 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 Ni3Sn2/nitrogen-doped graphene (NG) composite asseparator modifying material for lithium-sulfur batteries. The Ni3Sn2formed by dual metal salts Ni(NO3)2·6H2O and SnCl2·2H2O can adsorb polysulfide and catalyze its transformation to improve the electrochemical reaction kinetics. Moreover, the layered NG can not only disperse the Ni3Sn2particles, but alsoensure rapid electron transfer. Therefore, the lithium-sulfur battery with the Ni3Sn2/NG modified separator shows excellent electrochemical performance. At a current rate of 1 C, the lithium-sulfur battery with the Ni3Sn2/NG modified separator can provide a high initial discharge capacity of 1022.1 mAh g−1and maintain a reversible specific capacity of 758.3 mAh g−1after 400 cycles.