In Situ Fabrication of Graphdiyne Nanoisland Anchored Ti3C2Tx Film to Accelerate Intercalation Pseudocapacitance Kinetics

Abstract

AbstractA 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)–Ti3C2Tx electrode is reported with tunable interlayer spacing, abundant active sites, and extensive charge storage nanochannels. In particular, the GDY–Ti3C2Tx (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–Ti3C2Tx 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.