Two-step hydrothermal synthesis of hydrangea-like Bi2O2Se with high performance for supercapacitors

• Published in: Materials letters 2024-12, Vol.377, p.137559, Article 137559
• Main Authors: Yang, Shiju, Qian, Libing, Xie, Xiaobin
• Format: Article
• Language: English
• Subjects: 2-step hydrothermal method; Bi2O2Se; Bismuth vacancy; Hydrangea-like; Supercapacitors
• ISSN: 0167-577X
• DOI: 10.1016/j.matlet.2024.137559

[Display omitted] •Bi2O2Se was successfully synthesized by a simple 2-step hydrothermal method.•Bi2O2Se possesses a substantial specific surface area and abundant pore morphology.•The Bi2O2Se compound exhibits a high concentration of bismuth vacancies.•Bismuth vacancies expands the space between [Bi2O2]n2n+ and [Se]n2n– layers.•Bismuth vacancies increase the ion-insertion pseudo-capacitance in Bi2O2Se. The hydrangea-like structure of Bi2O2Se, composed of ultra-thin nanosheets, was prepared by a 2-step hydrothermal method for supercapacitor applications. The unique hydrangea-like structure of Bi2O2Se, characterized by a substantial specific surface area and abundant pore morphologies, facilitated the infiltration of electrolyte. The presence of bismuth vacancies not only enhanced the conductivity, but also increased the spacing between [Bi2O2]n2n+ and [Se]n2n– layers, creating room for K+ insertion/extraction and augmenting the surface-controlled pseudo-capacitance. Consequently, the hydrangea-like Bi2O2Se exhibited a high specific capacitance of 650 F/g at 1 A/g, excellent rate capability of 62 % from 1–20 A/g, and retained 80 % of its initial capacitance after 2000 cycles.