Separators Modified Using MoO2@Carbon Nanotube Nanocomposites as Dual-Mode Li-Polysulfide Anchoring Materials for High-Performance Anti-Self-Discharge Lithium–Sulfur Batteries

The commercialization of lithium–sulfur batteries (LSBs) remains difficult owing to the shuttle effect of soluble lithium–polysulfide and the poor redox kinetics of a traditional cell configuration without a sophisticated cathode design. To resolve these difficulties, we developed modified separators with electrically exploded MoO2@carbon nanotube (MoO2@CNT) nanocomposites. The embedded MoO2 nanoparticles demonstrated strong chemical anchoring properties with polysulfides; meanwhile, a porous CNT scaffold supported suppression of the shuttle effect and acted as an upper current collector. In addition, the mesoporous textural properties of a MoO2@CNT nanocomposite provide a suitable lithium-ion pathway with enhanced ionic conductivity and additional active sites for active sulfur during cycling; finally, a high utilization of sulfur is achieved in a reversible manner. The LSBs using the modified separator with the optimized MoO2@CNT nanocomposite exhibit high discharge capacities of 1067 mA h g–1 at 0.2 C after 100 cycles and significant cycling stability at 1 C. Also, an impressive anti-self-discharge feature and improved rate capabilities were achieved through the introduction of a MoO2@CNT nanocomposite. We believe that our approach can be used as a proof-of-concept for further research into effective methods to prepare modified separators with various electrically exploded carbon–metal oxide nanocomposites that can used in high-performance LSBs.