In Situ Fabrication of Graphdiyne Nanoisland Anchored Ti₃C₂T_x Film to Accelerate Intercalation Pseudocapacitance Kinetics

A key challenge in flexible supercapacitor is balancing the trade-off between high capacity and fast charging ability caused by dense structure-induced sluggish ionic diffusion and storage dynamics. Herein, a hydrogen-rich graphdiyne (GDY)–Ti₃C₂T_x electrode is reported with tunable interlayer spacing, abundant active sites, and extensive charge storage nanochannels. In particular, the GDY–Ti₃C₂T_x (12.6 wt.%) electrode has a remarkable volumetric capacitance (2296 F cm⁻³ at 1 A cm⁻³) and fast charging behavior (1262 F cm⁻³ at 50 A cm⁻³) resulting from the shortened transport pathways, enhanced ionic diffusion rate, and facilitated electrolyte mass transport. Moreover, an all-solid-state supercapacitor (ASSC) delivers a high volumetric energy density of 65.6 mWh cm⁻³, as well as long-term deformable cyclic stability and high capacitance retention properties under harsh conditions. Density functional theory calculations and molecular dynamic simulation demonstrate the fast electronic responsiveness of the GDY–Ti₃C₂T_x heterostructure owning to the stronger H⁺ electrostatic attraction, lower migration resistance, and accelerated intercalation pseudocapacitance kinetics. In situ X-ray diffraction reveals that a stable Ti─O─C bond bridged organic–inorganic heterostructure can tolerate the repeated high-current charge/discharge cycling process. The state-of-the-art ASSC delivers multiple functional outputs and shows great potential for efficient energy supply in practical applications.