Nitrogen-Doped Borane Cluster Network for High-Performance Supercapacitors Under Universal pH Conditions

Supercapacitors have garnered considerable attention as next-generation energy storage systems due to their high-power density, rapid charge-discharge kinetics, and long operational lifespan. In this study, we report the design and development of a nitrogen-doped activated borane (ActB), a porous borane cluster-based network, synthesized through the controlled cothermolysis of arachno-B₉H₁₃(NEt₃) and [Et₃NH][nido-B₁₁H₁₄] in toluene. The resulting polymeric materials integrate electron-rich nitrogen sites with the unique 3D boron cluster architecture, offering a synergistic platform for enhanced electrochemical performance. Electrochemical evaluation in a three-electrode system revealed a high specific capacitance of 607 F g^-1 at 0.5 A g^-1, with remarkable cycling stability, retaining 95% of the initial capacitance after 15,000 charge-discharge cycles. When configured into an asymmetric supercapacitor device using activated carbon as the negative electrode, the system achieved a specific capacitance of 354 F g^-1, along with an energy density of 25.6 Wh kg^-1 and a power density of 486.2 W kg^-1 at a current density of 0.5 A g^-1. The device also demonstrated long-term reliability, retaining 88% of its initial capacitance after 15,000 cycles. The outstanding performance is attributed to the integration of redox-active nitrogen functionalities and the inherent stability and tunability of the borane-based framework. This work establishes nitrogen-doped borane cluster polymers as a promising new class of electrode materials for high-performance supercapacitors and broader electrochemical energy storage applications.