H⁺-Induced 3D Porous Ti₃C₂T_x Foam Coupled with S Nanoparticles by the Drop Infusion Melting Method as a High Areal Loading Cathode for Li-S with Enhanced Performance

In this work, a Ti₃C₂T_x foam rich in -O functional groups was constructed by the H⁺-induced self-assembly and freeze-drying method, exhibiting a unique oriented three-dimensional porous structure. Subsequently, a S/Ti₃C₂T_x foam composite was prepared using the drop infusion melting method, in which S nanoparticles (30-100 nm) were uniformly anchored to the Ti₃C₂T_x surface through the Ti-S bond, serving as a cathode for lithium-sulfur batteries (LSB). The Ti₃C₂T_x foam exhibits a three-dimensional porous structure with a high specific surface area (42.8 m²/g), which promotes the uniform loading of sulfur (S), constructs fast migration channels for electrons and ions, and alleviates the volume expansion of S. Moreover, the Ti₃C₂T_x foam possesses a three-dimensional porous structure with abundant −O functional groups, which can provide both physical confinement and a chemical adsorption effect for polysulfides, effectively inhibiting the shuttle effect. Consequently, the S/Ti₃C₂T_x foam electrode with a 4.2 mg/cm² S loading exhibits excellent rate performance (1165, 1033, 862, and 646 mAh/g at 0.1, 0.2, 0.5, and 1 C, respectively). Meanwhile, with a 1.8 mg/cm² S loading, the electrode also exhibits good long-term cycling performance (723 mAh/g after 800 cycles, with a capacity retention of 64.9%).