Freestanding Double-Layer MoO₃/CNT@S Membrane: A Promising Flexible Cathode for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have been regarded as a promising candidate of secondary batteries to satisfy the enormous demand for electric vehicles and energy storage applications. However, Li–S batteries still suffer from severe capacity fading due to the shuttle effect of lithium polysulfides. Here, we develop a freestanding double-layer MoO 3 /carbon nanotube@S (FMC@S) membrane by hydrothermal and suction filtration strategy, without polymer binder and current collector substrate. FMC@S contains a polysulfide blocking layer and an active material layer. Except for S content, the two layers have the same components and are integrated together, so there is no distinct interface between the two layers, which can facilitate ion and electron transport. As a result, the FMC@S cathode delivers promising capacity retention and rate capability. The hierarchical integrated design provides a new strategy to develop high-performance flexible cathodes for Li–S batteries.