Multifunctional separator engineering with nanodiamond doped-rGO/MoO3 composites for high-performance lithium-sulfur batteries

Developing the battery separators has been an important strategy to improve the performance of lithium-sulfur batteries (LSBs). Here, we propose an innovative strategy involving the incorporation of oxygen-terminated nanodiamonds (OND) into the LSBs, and develop reduced graphene oxide-molybdenum trioxide composite doped with ONDs as a functional material for modifying polypropylene separator (OND-MoO 3 @rGO/PP). OND doping optimizes the structure of the MoO 3 @rGO composite, resulting in a larger specific surface area and a rich pore size distribution. The LSB with OND-MoO 3 @rGO/PP achieves an initial discharge-specific capacity of 1550.9 mAh g −1 at 0.2 C. The capacity fading rate per cycle after 700 cycles is just 0.072 % at 1 C. At a sulfur loading of 2.93 mg⋅cm −2 , the LSB with OND-MoO 3 @rGO/PP still delivers an initial discharge-specific capacity of 1174.5 mAh g −1 at 0.2 C, indicating that the OND-MoO 3 @rGO/PP separator demonstrates effective mitigation of the polysulfide shuttle effect and capacity fading during cycling in LSBs. The study offers a novel separator modification for developing high-performance LSBs. • Oxygen-terminated diamond-doped MoO 3 @rGO (OND-MoO 3 @rGO). • OND-MoO 3 @rGO were synthesized by a two-step hydrothermal-calcination method. • OND doping optimizes the structure of the MoO 3 @rGO. • Polypropylene separator modified with OND-rGO@MoO 3 (OND-MoO 3 @rGO/PP). • The cell with OND-MoO 3 @rGO/PP capacity fading rate after 700 cycles is 0.072 % at 1 C.