Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (3): 952-957.doi: 10.19799/j.cnki.2095-4239.2021.0106

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Electrochromic-supercapacitors based on tungsten oxide and prussian blue

Zhijie BI(), Ning ZHAO, Xiangxin GUO()   

  1. College of Physics, Qingdao University, Qingdao 266071, Shandong, China
  • Received:2021-03-16 Revised:2021-03-26 Online:2021-05-05 Published:2021-04-30
  • Contact: Xiangxin GUO E-mail:bizhijie@qdu.edu.cn;xxguo@qdu.edu.cn

Abstract:

The WO3 is a typical cathodic electrochromic material, which colors in the reduction (cation intercalation) state and fades in the oxidation (cation deintercalation) state. However, Prussian blue (PB) is a typical anodic electrochromic material, which colors in the oxidation (cation de-intercalation) state and fades in the reduction (cation intercalation) state. The electrochromic-supercapacitor was constructed based on the WO3 and PB films due to the matched color changes for WO3 and PB films under different ion-storage states. The WO3 and PB composite films were prepared on the surface of transparent conductive glasses using the pulsed laser deposition and electro-deposition methods. The symmetric electrochromic-supercapacitor was fabricated using WO3 and PB composite films as electrodes. The results showed that the WO3/PB composite film presents superior cycling stability with the areal capacitance retention of 83.8% after 200 cycles. In addition, the supercapacitor presents an optical contrast of 53.2% between the total coloring and bleaching states at 650 nm, which is ascribed to the synergetic color changes for WO3 and PB films under different voltages. Such supercapacitor exhibits different color changes under different charge-discharge states; thus, realizing the indication of energy-storage states through color changes. Our work pushes the combination of electrochromism and energy storage, leading to the visualization of energy-storage states for supercapacitors.

Key words: electrochromic, supercapacitor, tungsten oxide, Prussian blue, bi-functional

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