Highly efficient β-Bi2O3/Bi battery electrodes by reactive annealing from sol-gel precursors

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2025-01, Vol.705, p.135738, Article 135738
• Main Authors: Pellegrino, Giovanna, Mineo, Giacometta, Strano, Vincenzina, Marcellino, Gianluca, Pulvirenti, Luca, Ursino, Federico, Mirabella, Salvatore, Condorelli, Guglielmo G.
• Format: Article
• Language: English
• Subjects: Battery electrode; Bi2O3; Energy storage; Nano-porous thick film; Reactive annealing; Sol-gel
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2024.135738

The need of achieving low-impact and low-cost functional materials through sustainable and efficient methodologies is one of the goals of the current research in the field of materials science and energy storage. In this study, a new facile route for obtaining battery-like electrode Bi-based films is presented. Specifically, ∼1.3 μm-thick β-Bi2O3 films were prepared from oxynitrate via a simple sol-gel/elution process upon titanium foils, followed by annealing in forming gas at 350°C. A multi-technique approach, involving Raman, X-ray Photoelectron Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and optical characterization, demonstrates the formation of a nanocrystalline porous bismuth oxide (20–30 nm in size) consisting of β-Bi2O3 phase with the crucial presence of Bi0. Annealing at 350°C in different environments (i.e. air and N2), do not produce crystalline phases. The reported method improves the synthesis of β-Bi2O3 phase through a ∼1.3 μm-thick film realization and a controlled phase production by reactive annealing at moderate temperatures. Cyclic Voltammetry and Galvanostatic Charge Discharge analyses reveal a double-redox behaviour for the β-Bi2O3 /Bi0 battery electrode with a specific capacity (capacitance) of 195 mA*h/g (350 F/g) at 0.5 A/g. The data highlight the promising usage of sol-gel/elution for the realization of ∼1.3 μm-thick film for energy storage applications. [Display omitted] •A new elution method is settled for the deposition of ∼1.3 μm-thick films from sol-gel.•The reactive annealing in forming gas determines the formation of Bi/β-Bi2O3 at 350°C.•The Bi/β-Bi2O3 nanoporous films show a battery-like behavior in energy storage test.