Artificial three-dimensional inverse opal cathode host materials for lithium sulfur batteries

Abstract

Lithium-sulfur batteries (LSBs) are regarded as promising energy storage devices due to their high theoretical capacity. However, LSBs face great challenge in commercial uses due to their “shuttle effect”. In this work, a composite material consisting of N and O heteroatoms dispersed on three-dimensional macroporous glycine anhydride (3DMPGA) inverse opal structure is designed and synthesized by the one-step method. Compared with high temperature graphitization, low temperature pyrolysis of 3DMPGA consumes less energy. And precursor glycine is renewable, which is significant for reducing carbon emissions. The results show that 3DMPGA has an ordered porous inverse opal structure and uniform heteroatoms distribution. Lithium polysulfides are not only stored in the pores with spatial confinement but also anchored on the surface of pores via chemical adsorption, confirmed by adsorption tests and density functional theory calculation, respectively. The initial capacity of the 3DMPGA cathode at 0.5C is 848 mAh g−1, and the average attenuation rate for 300 cycles is only 0.14%. At a higher C-rate, the enhanced electrochemical performance of 3DMPGA is more obvious due to the dual-effect on mitigating the “shuttle effect”.