Three-dimensional Fe3O4/N-graphene sponge as an efficient organosulfide host for high-performance lithium-organosulfur batteries

The rapid capacity decay and unclear mechanism for the capacity fade limit the practical application of lithium-organosulfur batteries. Herein, we employ dimethyl trisulfide (DMTS) as a model compound to investigate the capacity fading mechanism and propose a solution to improve its cycling stability. Our results reveal that both DMTS and its discharge products (e.g., LiSCH3, LiSSCH3) are soluble in the electrolyte, leading to severe active material migration and loss, which becomes the predominant capacity fading mechanism. A three-dimensional nitrogen-doped graphene sponge decorated with Fe3O4 nanoparticles (3DFNG) is designed as a host for DMTS, which effectively confine the active material, enabling a specific capacity of 822 mA h g(-1) at C/10 rate and good cycling stability for 500 cycles with a capacity decay of as low as 0.09% per cycle. This work is expected to open up a promising direction to realize highly efficient hosts for lithium-organosulfur batteries.