A study on the electrochemical energy storage mechanism of Bi2O2Se nanosheets

Bismuth selenium oxide (Bi2O2Se), as a typical two-dimensional layered structure material, has been applied widely in electronics, optoelectronics, and electrochemical energy storage devices. However, the inner energy storage mechanism is not yet clear enough for its further development and applications. Herein, Bi2O2Se nanosheets have been prepared by hydrothermal method and used to construct electrodes as the electrochemical energy storage device. After careful analysis and characterization, the energy storage mechanism of Bi2O2Se nanosheets has been revealed. The valence changes process of the bismuth element and the insertion of potassium ion are the main reasons for its high capacity. Additionally, after ultrasonic crushing treatment, the specific capacitance of Bi2O2Se nanosheets electrode is 728 F/g, which has increased by 16.3 % compared with the original Bi2O2Se nanosheets. The enhanced performance can further reflect the correctness of the mechanism explanation. The results obtained establish a data foundation and delineate a pathway for the practical application of bismuth-based compounds within the energy storage sector.