In‐Situ Triphasic Engineering of Few‐Layer Borophene/Graphene Hybrid with a Binary MOF for Flexible and High‐Performance Sodium‐Ion Supercapacitor

Abstract Advancing high‐performance, compact, and flexible energy storage devices is essential for the progress of next‐generation wearable electronics. In this study, a ternary hybrid electrode is fabricated by integrating few‐layered Borophene nanosheets with amine‐functionalized reduced graphene oxide (Amine‐rGO), followed by the in‐situ growth of NiCo‐MOF. The synthesized composite takes advantage of the rigidity and high surface area of Borophene, the pseudocapacitive behavior of NiCo‐MOF, and the structural flexibility and electrical conductivity of amine‐rGO to enhance overall electrochemical performance. A flexible interdigitated Na‐ion hybrid capacitor is constructed employing the amine‐graphene/Borophene (AGB) composite as the anode and AGB/NiCo MOF as the cathode, with a PVA–NaOH gel electrolyte. The device delivers an output of 1.4 V, reaching a high volumetric energy density of 4.92 mWh cm −3 at a power density of 78.3 mW cm −3 , and sustains 1.85 mWh cm −3 at 1566.4 W cm −3 . It retains 86% of its original capacitance after 20 000 cycles and remains electrochemically stable under repeated mechanical bending and twisting, highlighting its mechanical durability. Moreover, the device showcases practical functionality by lighting a red light‐emitting diode (LED). This study establishes an efficient and scalable approach for employing few‐layered Borophene nanohybrids in flexible Na‐ion interdigitated supercapacitors with enhanced volumetric energy and power densities.