Engineered\n2D Boron Nitride Flexible Electrodes for\nSupercapacitors

Supercapacitors\npresent a substantial surge forward in renewable\nenergy storage technology. Their remarkable power density and rapid\ncharge and discharge capabilities outstrip those of traditional batteries,\nopening up exciting possibilities for storing renewable energy from\nintermittent solar and wind power sources. So far, high power density\ndevices have been accomplished by combining electric double-layer\ncapacitors (EDLC) with pseudocapacitors such as polyaniline (PANI).\nWe introduce 2D heterojunction hybrid supercapacitors integrating\niron-doped boron nitride (Fe-BN) electrodes with PANI. This Fe-BN/PANI\nhybrid shows excellent stability under mechanical, thermal, and electrochemical\nstresses and forms a flexible, high-efficiency supercapacitor. The\ncapacitance of the hybrid 2D device is 721 F g<sup>–1</sup> at 1 A g<sup>–1</sup> current density in a three-electrode\nsetup. A two-electrode symmetric cell assembly prepared using this\nhybrid system demonstrates energy and power densities of 15.25 Wh\nkg<sup>–1</sup> and 1000 W kg<sup>–1</sup> at 2 A g<sup>–1</sup> current density. Notably, the symmetric cell retains\n81% of its specific capacitance after 10000 charging–discharging\ncycles at 10 A g<sup>–1</sup>, highlighting its potential as\na durable and efficient electrode material for supercapacitors.