Ultrathin Two-Dimensional Fe–Co Bimetallic Oxide Nanosheets for Separator Modification of Lithium–Sulfur Batteries

Abstract

The shuttle effect is understood to be the most significant issue that needs to be solved to improve the performance of lithium–sulfur batteries. In this study, ultrathin two-dimensional Fe–Co bimetallic oxide nanosheets were prepared using graphene as a template, which could rapidly catalyze the conversion of polysulfides and inhibit the shuttle effect. Additionally, such ultrathin nanostructures based on graphene provided sufficient active sites and fast diffusion pathways for lithium ions. Taking into account the aforementioned benefits, the ultrathin two-dimensional Fe–Co bimetallic oxide nanosheets modified separator assembled lithium–sulfur batteries delivered an incredible capacity of 1044.2 mAh g−1 at 1 C and retained an excellent reversible capacity of 859.4 mAh g−1 after 100 cycles. Even under high loading, it still achieved high area capacity and good cycle stability (92.6% capacity retention).

Keywords

• two-dimensional materials
• multifunctional separators
• CoFe₂O₄
• lithium–sulfur batteries