Enhanced dielectric and ferroelectric response of rGO incorporated K0.5Na0.5NbO3 hybrid system

Abstract

Composite materials offer a wide range of possibilities to enabling advancements in renewable energy storage solutions and efficiency enhancements. The present work investigates the effect of reduced graphene oxide (rGO) incorporation on the structural, impedance, and ferroelectric properties of K_0.5Na_0.5NbO₃ (KNN). Samples were synthesized using electrospinning and conventional solid-state methods. The X-ray diffraction analysis confirmed the formation of a well crystallized perovskite phase structure, with rGO incorporation reducing the crystallite size from 42.57 nm to 31.80 nm indicating structural modifications. Rietveld refinement further confirmed the crystal structures of the ceramics with chi-square χ² values of 2.28 and 1.76 for KNN and KNN/rGO, respectively. Field emission scanning electron microscopy (FE-SEM) analysis showed the large grains indicating enhanced crystallinity or material aggregation due to rGO. The particle size distribution analysis showed the average sizes of 163.62 nm for KNN and 183.51 nm for KNN/rGO. Dielectric studies as a function of temperature and frequency exhibited phase transitions, with an increased dielectric constant (ɛ_r) reaching 23,769 for KNN/rGO while 7600 for KNN at 550 °C in the low frequency region. A typical semicircle response has been showed by the impedance diagrams for KNN and KNN/rGO showing the presence of grain/bulk effect of the material. The ferroelectric behaviour was enhanced by rGO incorporation resulting in increased conductivity and remanent polarizations (P_r), with P_r increased from 4.43 μC/cm² to 6.34 μC/cm² at 100Hz along with increased coercive field (E_c)

The results presented herein indicate that rGO significantly enhances the dielectric, and ferroelectric properties of KNN, making it a promising candidate for advanced energy applications.