Exploring the battery-like pseudocapacitive behavior of bismuth ferrite-N doped rGO composites

Abstract

Perovskite bismuth ferrite (BiFeO₃) has emerged as a promising material for battery-supercapacitor hybrid (BSH) devices, owing to the redox activity of Bi³⁺ and Fe³⁺ ions. Integrating BiFeO₃ with two-dimensional (2D) materials effectively mitigates phase decomposition during charge-discharge cycles, thereby improving both performance and stability. In the present study, BiFeO₃/N-rGO composite is prepared using a one-pot hydrothermal method and is used as the electrode material to understand its energy storage behavior. The composite exhibited a crystallite size of 21 nm with suppression of Raman vibrational modes of BFO (4A₁+9E) with I_d/I_g ratio of 0.97, indicating successive anchoring of BFO onto the sheets of N-rGO exhibiting particle-on-a-sheet morphology. Subsequent investigation into the composite material's potential to store charge reveals that it behaves like a battery-like pseudo-capacitor, displaying a specific capacitance of 186, 328, and 440 Fg^-1 (in 0.5 M KOH, 1 M KOH, and 2 M KOH, respectively) at a current density of 1 Ag^-1 with a capacity value reaching up to 45, 65 mAhg⁻¹ (1 M KOH and 2 M KOH, respectively). Whereas the symmetric device constructed has an increase in power density from 591 to 2620 WKg^-1 with capacitance reaching up to 35 Fg⁻¹. During cyclic stability testing over 1500 cycles, the material retained 24 % of its initial capacitance and exhibited a coulombic efficiency of 51 %. Further, results from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirm that the material possesses a redox behavior indicating a strong faradaic/diffusion-controlled process, indicating both supercapacitor and battery-like behavior. The results demonstrate that it could be widely applied to establish a supercapattery device which will offer a promising alternative to traditional batteries for sustainable and high-performance applications.