Agrawal, Bhavi Sharma, Aditya Chae, Keun Hwa Varshney, Mayora Brajpuriya, Ranjeet Kumar Won, Sung Ok Kumar, Shalendra 2026-02-03T09:00:18Z 2026-02-03T09:00:18Z 2026-02-02 2026-02 2352-152X https://pubs.kist.re.kr/handle/201004/154164 The correlations among the Bi stoichiometry, secondary phase formation, electronic structure, and electrochemical behaviour have been established in sol-gel auto-combustion prepared Bi1+xFeO3 (x = 0.00–0.10) nanocrystals. A quantitative phase analysis, from Rietveld refined X-ray diffraction (XRD) patterns, conveyed a minimum secondary phase segregation, ~ 4.1 %, in Bi1.05FeO3. The Bi3+ and Fe3+ ions have been confirmed in the Bi1+xFeO3 samples through Fe L-edge and Bi N-edge X-ray absorption spectroscopy (XAS) spectra. The O K-edge XAS spectra indicated a reduction in unoccupied Bi 6sp states and, thus, endorsed the band gap energy decrease, from 2.1 eV to 1.93 eV, and oxygen ion vacancy formation. Electrochemical studies revealed that Bi1.05FeO3 exhibited the highest capacitance of 222.2 F/g and 117.3 F/g in 1 M KOH and 1 M NaOH electrolytes, respectively. An asymmetric supercapacitor device, a Swagelok cell (Bi1.05FeO3//activated carbon, 1 M KOH), has offered a high energy density of 124.9 Wh/kg (at a power density of 1750 W/kg) with 88 % capacitance retention after 10,000 cycles. English Elsevier BV Structure-controlled electronic structure and electrochemical energy storage mechanisms in Bi-rich BiFeO3 based asymmetric supercapacitor devices Article 10.1016/j.est.2025.120230 1 Journal of Energy Storage, v.147 Journal of Energy Storage 147 N scie scopus 001660974400007 2-s2.0-105027147797 Energy & Fuels Energy & Fuels Article LOW-TEMPERATURE SYNTHESIS X-RAY-ABSORPTION BISMUTH FERRITE MULTIFERROIC PROPERTIES MAGNETIC-PROPERTIES SPECTROSCOPY DESIGN Hybrid supercapacitors Bismuth ferrite XAS Energy density