Highly efficient electro-optically tunable smart-supercapacitors using an oxygen-excess nanograin tungsten oxide thin film

Abstract

Next-generation electronic technology requires the use of advanced energy storage devices with integrated functionality to fulfill key application requirements. A smart supercapacitor shares the same electrochemical processes as a conventional energy storage device in addition to electrochromic functionality. It can sense the energy storage level and can display it in a noticeable manner, which results in added convenience to everyday applications. In this study we have developed a smart supercapacitor that uses tungsten oxide nanograin thin film to provide the combined advantages of energy storage and electrochromism. The nanostructured tungsten oxide is dark blue in the charged state and becomes transparent in its discharged state; and it has a specific capacitance of 228 Fg −1 at 0.25 Ag −1 with a quite large potential window of 1.4 V. It is highly durable, exhibits good electrochemical stability over 2000 cycles, retains a significant charge storage of 75%; and exhibits a high coloration efficiency of ~170 cm 2 /C with an optical modulation of 82%. The smart-supercapacitor fabricated with this material exhibits a superb combination of 2 energy storage and electrochromic features in one device to monitor the energy storage level through visible changes in color.

Nanoflake NiMoO4 based smart supercapacitor for intelligent power balance monitoring

“…A literature survey on the present status of the smart supercapacitor technology, based on TMOs and complex compounds, is presented in Figure 1, together with our results [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The wavelength on the horizontal axis is associated with the color of the electrode materials in the colored state.…”

“…Electrosorption or intercalation processes occur on the surface of an electrode accompanying an electron chargetransfer between electrolyte and electrode, and this reversible reaction often changes the color of the electrode (known as electrochromism) [5]. Devices having such dual functionality are called smart supercapacitors [5,[6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Smart supercapacitors store energy as a normal supercapacitor and sense the level of energy stored by changing visual color.…”

“…Well-known materials such as WO 3 and its complex compounds, polyaniline (PANI), carbon nanotubes (CNT), and nickel oxide (NiO) have been investigated as smart supercapacitors. Attempts have been made to fabricate nanostructured materials to enhance the electrochemical reaction and efficiency using different techniques such as Rf-magnetron sputtering, electrodeposition, hydrothermal, thermal evaporation, spin coating, and chemical vapor deposition [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The techniques used for the synthesis of nanostructured materials need a long time and a sophisticated experimental setup.…”

Review on Recent Progress in the Development of Tungsten Oxide Based Electrodes for Electrochemical Energy Storage

“…Inamdar et al. prepared smart SCs by using an oxygen‐rich nanograin WO 3 electrode fabricated through radiofrequency (RF) magnetron sputtering . Excess oxygen played a very significant role in the formation of distorted tunnel structures in all directions.…”

“…prepared smart SCs by using an oxygen-rich nanograin WO 3 electrode fabricated through radiofrequency (RF) magnetron sputtering. [82] Excess oxygen played av ery significant role in the formation of distorted tunnel structures in all directions. These tunnelstructures were beneficial for the accommodation of more electrolyte ions and for enhancing the capacitive performance.…”