Multifunctional PANI/Ti₃C₂T_x MXene nanocomposites for enhancing Na-S battery performance

The application of PANI/MXene as an interlayer maintains a capacity retention rate of 94.7% after 500 cycles at a current density of 1C (C = 1675 mAh g⁻¹) in practical sodium-sulfur (Na-S) batteries. In comparison, the cell with MXene interlayer demonstrates a reversible capacity retention rate of merely 71.8% after the same number of cycles, which is lower than the cell with PANI/MXene. The cell with PANI/MXene separator exhibited capacities of 931.2 mAh g⁻¹ and 701.2 mAh g⁻¹ at a current density of 1C and 2C, respectively. When the current density was returned to 1C and 0.5C, the capacities were maintained at 728.5 mAh g⁻¹ and 917.5 mAh g⁻¹, respectively, indicating a capacity recovery rate of 98.4%.The EDX maps reveal a uniform distribution of the key elements that make up the MXene nanosheets, including Ti, C, N, and O alongside with S, which proved the agglomeration of polysulfides species on the separator surface after 500 cycles. The enhanced adsorption of polysulfide chains in PANI/MXene as an interlayer in Na-S batteries could open a new avenue as a promising separator for the next generation of high-performance Na-S batteries.