Improvement of the electrochemical performance of Bi2O3 by electron beam irradiation

The method of preparation is a critical factor affecting the structure and properties of Bi 2 O 3 material. In this work, Bi 2 O 3 was synthesized through calcination (denoted as Bi 2 O 3 –C) and hydrothermal methods (denoted as Bi 2 O 3 –H), utilizing bismuth-based metal–organic framework (Bi–MOF) as the precursor. As an electrode material for supercapacitors, Bi 2 O 3 –H demonstrated outstanding rate performance (515 F g −1 at 50 A g −1 ) and remarkable cycle stability (74% retention after 4000 cycles). Subsequently, the Bi 2 O 3 -H underwent further processing through electron beam irradiation (EBI), resulting in a sample designated as Bi 2 O 3 –I. Following EBI treatment, the crystalline characteristics of Bi 2 O 3 –I and the concentration of oxygen vacancies (OVs) exhibited a significant improvement, thereby augmenting the material's conductivity. Because the positively charged OVs can quickly attract OH − from the electrolyte to the electrode surface, thereby accelerating the REDOX reaction, the current control mechanism of Bi 2 O 3 –I is partially derived from a surface-controlled pseudo-capacitance process. The irradiated Bi 2 O 3 -I electrode demonstrated superior capacitance (990 F −1 at 2 A g −1 ), enhanced rate performance (585 F −1 at 50 A g −1 ), and remarkable cycling stability (83% retention after 4000 cycles).