Invasion of Zinc in BiFeO₃/Bi₂₅FeO₄₀ Perovskite-Structured Material as an Efficient Electrode for Symmetric Supercapacitor

BiFeO3/Bi25FeO40 (BFO) and zinc-substituted BiFeO3/Bi25FeO40/Bi38ZnO(58) (BFZO1, BFZO2, and BFZO3) were successfully synthesized by a hydrothermal method at different concentrations of Zn:Fe. The BFZO1 showed the highest electrochemical behavior than other composites. The X-ray diffraction and Raman analyses of BFZO1 confirmed the formation of zinc-substituted BiFeO3/Bi25FeO(40)/Bi38ZnO58. The structural analysis confirmed the agglomerated flake-like morphology from field emission scanning electron microscopy and transmission electron microscopy. BFZO1 showed a high surface area of 56.59 m(2)g(-1) and a high pore diameter of 6.71 nm, offering a higher specific capacitance of 1087 F g(-1) at a current density of 1 A g(-1) in 3 M KOH as an electrolyte. Furthermore, the symmetric device fabricated from BFZO1 showed the highest specific capacitance of 236 F g(-1), a specific energy of 32 W h kg(-1), and a specific power of 1000 W kg(-1) at a current density of 0.5 A g(-1). The reversibility and cyclic stability of the device showed capacitance retention of 84% and Coulombic efficiency of 91% up to 10,000 cycles at a current density of 3 A g(-1). The resulting BFZO1 delivers excellent electrochemical performance in supercapacitor applications.