New flexible separators for modification of high-performance lithium–sulfur batteries

High energy density lithium-sulfur batteries (LSBs) are regarded as a promising yet challenging advancement in battery technology. The frequent movement of polysulfide intermediates and sluggish solid-solid reaction kinetics commonly result in irreversible sulfur depletion, diminished coulombic efficiency, and restricted operational lifespan. The development of functional separators for LSBs is recognized as a highly effective approach to address these issues. The construction of functional separators has the potential to effectively mitigate the shuttle effect of polysulfides and promote the uniform deposition of lithium ions, thereby facilitating the formation of dendrite-free anodes. This paper provides a comprehensive overview of the modification techniques commonly employed for enhancing the performance of LSB. These techniques include the utilization of monatomic catalysts, transition metal oxides, transition metal carbides, transition metal sulfides, transition metal nitrides, transition metal borides, transition metal phosphides, transition metal selenides, heterostructures of transition metal compounds, as well as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). Additionally, recent advancements in this field are integrated to address existing limitations and propose further enhancements. Furthermore, it integrates recent advancements in order to address the deficiencies and enhancements of functional diaphragms. The conclusion of the article emphasizes the superior commercial potential of the new flexible separator compared to the traditional polyolefin separator, indicating a promising direction for the future development of functional separators in order to enhance the performance of LSBs.