Ordered porous metal oxide embedded dense carbon network design as high-performance interlayer for stable lithium-sulfur batteries

Abstract

The design of multifunctional interlayer is important for the suppression of lithium polysulfides (LiPSs) shuttle effect in lithium-sulfur (Li-S) batteries. Herein, a multifunctional interlayer fabrication strategy is developed by depositing ordered porous metal oxide embedded with nitrogen-doped carbon nanotubes (NCNT) on the carbon nanofibers (CNFs) skeleton. In this design strategy, three-dimensional ordered macroporous N, Co-doped titanium oxides (N,Co-TiOx) is uniformly deposited on CNFs network, then in-situ growth of NCNT is implemented within the ordered porous oxides framework and CNFs, forming dense-structured adsorption/catalytic multifunctional interlayer (N,Co-TiOx/NCNT@CNFs). The ordered porous N,Co-TiOx together with the implemented NCNT not only provides an effective physical barrier for polysulfides diffusion, but also offers strong chemical interaction with LiPSs adsorption and promoted catalytic conversion kinetics. With these merits, the Li-S battery with N,Co-TiOx/NCNT@CNFs interlayer delivers an impressive rate capability of 638 mAh g-1 at a current density of 5 C. The cell also shows excellent cycling performance with a capacity decay of 0.033 % per cycle after 500 cycles at 1 C. More importantly, the Li-S pouch cells with N,Co-TiOx/NCNT@CNFs interlayer achieve a capacity of 806 mA h g−1 at sulfur loading of 4.0 mg cm−2 after 50 cycles at 0.1 C. This ordered porous metal oxide embedded dense carbon network design provides alternative strategy for the development of high-performance Li-S batteries interlayer.