Bridging Monolayer MXenes With PEDOT:PSS for High‐Mass‐Loading Ultrahigh‐Rate Supercapacitors

ABSTRACT Supercapacitors with high mass loadings (>10 mg cm ^{– 2} ) typically struggle to deliver ultrahigh‐rate performance because of sluggish mass and charge transport. This challenge is further exacerbated when using 2D electrode materials, which tend to undergo random self‐restacking driven by weak interlayer interactions. Here, we report a unilaminating and bridging strategy to construct ordered poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)–bridged Ti ₃ C ₂ T _x MXene (sMX‐PP) by finely modulating these weak interactions. The bridging mechanism arises from hydrogen bonding and electrostatic interactions between PEDOT:PSS and single‐layer Ti ₃ C ₂ T _x , effectively preventing restacking and promoting ion/electron transport. As a result, the sMX‐PP electrode with a high mass loading of 11.2 mg cm ⁻² delivers a specific capacitance of 165 F g ⁻¹ at an ultrahigh current density of 100 A g ⁻¹ . Furthermore, asymmetric supercapacitors assembled with activated carbon retain 58% of their capacitance as the current density increases from 3 to 70 A g ⁻¹ . This work provides a feasible approach to mitigating the performance degradation of MXene electrodes under simultaneous ultrahigh‐rate and high‐mass‐loading conditions, thus advancing the practical deployment of supercapacitors in ultrahigh‐power applications.