Lithium-sulfur batteries are heralded as the next-generation energy storage systems due to their exceptional theoretical discharge capacity (1675 mAh g^-1) and energy density (2600 W h kg^-1) [1]. However, their commercialization faces significant hurdles: the low electrical conductivity of sulfur and its compounds, substantial volume expansion during cycling, and the lithium polysulfide shuttle effect. These challenges lead to poor electrochemical performance, limited cycle life, and reduced rate capability [2,3].

In our current research aimed at overcoming these major challenges, we have developed a composite based on biomass-derived graphene-like porous carbon and MXene, which we used to modify the separator. The graphene-like porous carbon was produced by carbonizing biomass waste followed by thermochemical activation with potassium hydroxide (1:4). This process yielded carbon with an increased specific surface area of 2200 m²/g and significant mesoporosity, with an average pore size of 2-4 nm [4]. Concurrently, MXene (Ti₃C₂Tx) was synthesized by etching the aluminum layer from a titanium-based MAX phase. The chemical composition, morphological features, and microstructure of the prepared materials were thoroughly investigated using various techniques, including SEM, TEM, Raman spectroscopy, XPS, and XRD. The obtained composite was applied to a commercial Celgard separator using the doctor blade technique, with polyvinylidene fluoride dissolved in N-methyl-2-pyrrolidone as a binder.

As a result of the C/MXene separator modification, the assembled lithium-sulfur cell delivered an initial discharge capacity of 1620 mAh g⁻¹ at 0.2 C and maintained a capacity greater than 1050 mAh g⁻¹ after 100 cycles, with an average Coulombic efficiency of 97%. Further electrochemical tests of the cells are currently under investigation.

Acknowledgments

This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP13067625).