Hierarchically Structured CsPbBr ₃ @Ti ₃ C ₂ T _<i>X</i> Nanohybrid Frameworks for High-Performance Supercapacitors

Supercapacitors are promising energy-storage devices owing to their rapid charge–discharge capability and sustainability, yet their performance is limited by the lack of stable high-efficiency electrode materials. Among emerging candidates, CsPbBr3 perovskite quantum dots (PQDs) exhibit flexible ionic-electronic conductivity, a narrow band gap, and excellent charge–transport properties, making them attractive for next-generation energy-storage applications. Yet, their poor cycling stability under extended operation limits practical performance. In contrast, MXenes (Ti3C2TX), two-dimensional transition metal carbides, and nitrides possess outstanding metallic conductivity, hydrophilicity, abundant surface terminations, and robust structural stability, although restacking of nanosheets can hinder ion accessibility. Herein, a hierarchical CsPbBr3@Ti3C2TX nanocomposite was synthesized via an in situ hot-injection method to integrate the complementary advantages of both components. The resulting hybrid exhibits a large surface area, enhanced electron-ion transport, and abundant active sites, leading to remarkable electrochemical performance. When tested as a supercapacitor electrode in 5 M KOH electrolyte, it achieved a specific capacitance of 488 F/g at 1 A/g and retained 86% after 4000 cycles at 5 A/g, demonstrating its potential as a durable and high-performance electrode for advanced energy storage applications. TDOS analysis within the PBE framework reveals pronounced interfacial coupling and electronic redistribution in the CsPbBr3@Ti3C2TX nanocomposite yielding to enhanced charge accumulation (Qa = 628 μC/cm2 and Qc = 572 μC/cm2) and quantum capacitance (CQ = 452 μF/cm2), endorsing its potential as a high-performance and durable supercapacitor electrode.