Multifunctional Ti3C2Tx MXene/carbon nanotube interlayer as a polysulfide electrocatalyst with a high sulfur loading cathode in pre-lithiation Si/S batteries

Abstract

A significant area of current research is on the advancement of high-capacity anodes that exhibit outstanding high-rate cycling performance for the next generation of sulfur-based batteries. This study introduces an innovative method for fabricating Ti₃C₂T_x MXene/CNT interlayers through the application of sonication and filtration techniques. In this investigation, carbon nanotubes (CNTs) were employed due to their remarkable mechanical strength and superior electrical conductivity for the high-rate performance of Ti₃C₂T_x coating on glass fiber separators. By integrating the horizontal Ti₃C₂T_x layers and establishing a conductive network on the surface, CNTs reinforce the internal structure and mitigate the shuttle effect in pre-lithiation Si–S batteries. Following 500 cycles, the pre-lithiation S–S battery featuring a Ti₃C₂T_x MXene/CNT interlayer retains approximately 85% of its capacity. Thanks to the distinctive architecture of Ti₃C₂T_x/CNT, the battery achieves a reversible capacity of 1047 mAh g⁻¹ at a rate of 0.5 C and an impressive capacity of 1207.3 mAh g⁻¹ at a rate of 0.2 C. The capability of the Ti₃C₂T_x/CNT to recover to 1027 and 1091 mAh g⁻¹, respectively, when the current rate is suddenly altered from 1.0 C to 0.5 C and 0.2 C, demonstrates the structural integrity of the interlayer and its effective lithium polysulfide (LiPS) adsorption properties.