Synergistic adsorption-trapping in conductive polymer modulated MXene anodes enables stable sodium storage

Sodium-ion batteries (SIBs) demand anode materials that achieve both fast kinetics and high capacity. Ti 3 C 2 T x MXene exhibits great potential in SIB applications due to its excellent conductivity and abundant surface functional groups. However, challenges such as low specific capacity and sluggish Na + transport kinetics still remain. In this study, a novel conductive polymer engineered MXene composite was proposed. PEDOT: PSS was utilized to enhance the Na + storage capacity and kinetics simultaneously for MXene. Specifically, the sulfonate groups of PSS provide strong binding energy with Na + , facilitating the desolvation process. The PEDOT with abundant S/O atoms provides more active sites for Na + storage. Meanwhile, an efficient electron transport pathway was constructed relying on the delocalized electron, contributing to outstanding rate performance. By deeply experimental verification and theoretical calculations, an “adsorption-trapping” Na + storage mechanism was summarized in this composite. The electrode demonstrates a reversible capacity of 110 mAh g −1 maintained over 800 cycles at 1000 mA g −1 current density. This study provides new insights into the rational design of MXene-polymer composites and advances the application of polymeric materials in electrode systems.