Citric acid-assisted chemical engineering of Bi2O3 thin films via SILAR for high-performance asymmetric supercapacitors

초록

Energy storage technologies are essential for the development of sustainable and reliable power systems. In this study, a facile citric acid-mediated synthesis of bismuth oxide (Bi2O3) thin films is reported using the simple successive ionic layer adsorption and reaction (SILAR) technique for high-capacity asymmetric supercapacitor applications. A series of Bi2O3 electrodes (BiO-1 to BiO-5) was prepared by varying the citric acid concentration in the cationic precursor solution. A uniform nanoparticle film was observed for the BiO-3 electrode prepared with a citric acid concentration of 0.0375 M. This electrode exhibited excellent electrochemical performance due to enhanced ion/electron transport and the presence of numerous electrochemically active sites. The BiO-3 electrode demonstrated exceptional specific capacitance (Cs) and areal capacitance (Ca) values of 1044 F g- 1 and 1.096 F cm- 2, respectively, at a current density of 3 mA cm- 2, outperforming the other SILAR-derived electrodes. To evaluate its practical applicability, an aqueous asymmetric supercapacitor (AASC) device (BiO3//KOH//MnO2) was assembled using the BiO-3 electrode as the anode and MnO2 electrode as the cathode. The fabricated AASC device delivered a Cs of 124.57 F g- 1 at a current density of 3 mA cm- 2, with a maximum specific energy of 44.29 Wh kg- 1 at a specific power of 3840 W kg- 1, while maintaining an impressive capacitance retention of 84.24% over 2500 charge-discharge cycles. These results highlight the potential of the Furthermore, the fabricated device successfully powered a mini-fan, demonstrating the practical feasibility of

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