Ultrasound-assisted fabrication of a new nanocomposite electrode of samaria and borazon for high performance supercapacitors

•A novel samaria/borazon (O3Sm2/BN) nanocomposite was prepared by simple sonochemical method.•The nanocomposite was used as an electrode material for supercapacitors.•High capacitance of 414 Fg−1 was achieved at 0.25 Ag−1.•Superior cyclability with capacity retention of 92.5% in 5000 cycles. The fabrication of hetero structured materials with supercapacitor applications for industrial use remains a key challenge. This work reports a new supercapacitor material with high capacitance, comprising samaria and borazon (O3Sm2/BN) synthesized ultrasonically (40 ± 3 kHz, 200 W). The successful synthesis, probable interfaces between O3Sm2 and BN and thermal stability of the nanocomposite were studied by UV–Vis. and FT-IR spectroscopies, X-ray diffraction (XRD) and thermo gravimetric analyses (TGA). The morphology of nanocomposite was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Elemental mapping analysis and energy dispersive X-ray analysis (EDAX) confirmed the elements present in the material. This supercapacitor material shows a maximum discharge capacitance of 414 Fg−1 at 0.25 Ag−1 and an exceptional retention of specific capacitance (92.5%) in 5000 cycles. Such nanocomposite with better specific capacitance and charge/discharge rates makes it a right candidate as next generation supercapacitor, which certainly finds applications in various unconventional energy storage devices.