Reversible discoloration behavior of Bi2O2Se nanosheets in photoelectrochemical systems

Abstract

Electrochromic materials are substances that undergo the implantation or removal of electrons and ions in response to an electric field, which is redox reactions. These materials can change from one color to another and exhibit a reversible color change after a reverse voltage is applied. In this study, we report a novel material, Bi₂O₂Se, capable of both electrochromic and electrochemical energy storage. We successfully synthesized Bi₂O₂Se nanosheets using a hydrothermal method. Electrochemical tests on the Bi₂O₂Se nanosheets were conducted utilizing a three-electrode system at an electrochemical workstation. Under the influence of an electric field, the Bi₂O₂Se nanosheets transitioned from gray to yellow. This discoloration behavior was reversible upon applying reverse voltage, thereby exhibiting an electrochromic effect. Discharge at a voltage of 0 V after discoloration, resulting in reverse current generation. During this discharge process, the color of the Bi₂O₂Se electrode gradually recovers, exhibiting its energy storage capability. These findings suggest that Bi₂O₂Se nanosheets hold promise for potential applications that integrate both electrochromic functionality and energy storage capabilities. In the near future, they are likely to have a substantial impact on our daily lives.