Optimizing (1‐x) BiFeO ₃ ‐xCaTiO ₃ Perovskites: A Pathway to Efficient Flexible Energy Storage

Abstract New advanced functional material manufacturing and electrode design are the keys to developing the next generation of smart energy storage devices. This study explores the electrochemical performances of (1‐x) BiFeO 3 ‐xCaTiO 3 ( x = 0.4, 0.5, 0.6) (BFO‐CTO) perovskite for flexible electrochemical capacitors (ECs). BFO‐CTO are synthesized via solid‐state reaction, ensuring phase purity, while electrodes are printed on a flexible graphene sheet. X‐ray photoelectron spectroscopy (XPS) confirmed the mixture of metallic bismuth (Bi (0) ) and Bi 2 O 3 (Bi 3+ ), enhancing charge through redox activity and conductivity. The 60BFO‐40CTO composition exhibited a crystalline perovskite structure with high conductivity (14.03 kS.m −1 ) and hydrophilic properties (contact angle 40.3°). This resulted in a high electrochemically active surface area of 1.059 x10 −3 cm 2 and a specific capacitance of 2.79 mF.cm −2 in the symmetric EC. The asymmetric BF6CT4‐G‐EC, configuration achieved approximately an 80% increase in capacitance compared to the symmetric counterpart. It retained ≈90% of its initial capacitance after 6000 cycles, and maintained ≈72% capacity after 3000 cycles under 40° bending. These results highlight the potential of BFO‐CTO perovskites as high‐performance electrode materials for flexible energy storage applications.