What About Electrochemical Behaviors for Aurivillius-Phase Bismuth Tungstate? Capacitive or Pseudocapacitive

Researchers mainly explore the mechanism of pseudocapacitance through studying electrode materials with Faraday pseudocapacitive behavior. Here, we found that Bi2WO6, a typical layered perovskite material with Aurivillius phase, showed nearly ideal pseudocapacitive behavior. The cyclic voltammetry curve is approximately rectangular in shape, with no redox peaks, which is similar to that of carbon materials. And the shape of the galvanostatic charge-discharge curve is close to an isosceles triangle. In addition, kinetic analysis demonstrated that the electrochemical process of the A-Bi2WO6 electrode is mainly controlled by the surface, not diffusion. The A-Bi2WO6 electrode material presents great volumetric specific capacitance of 466.5 F cm-3 at 0.5 A g-1. These electrochemical properties confirm that Bi2WO6 material can serve as an ideal support material to study the pseudocapacitive mechanism, and it is the first material with perovskite-like structure that exhibits pseudocapacitive behavior.