Abstract
A smart supercapacitor shares the same electrochemical processes as a conventional energy storage device while also having electrochromic functionality. The smart supercapacitor device can sense the energy storage level, which it displays in a visually discernible manner, providing increased convenience in everyday applications. Here, we report an electro-optically tunable smart supercapacitor based on an oxygen-rich nanograin WO3 electrode. The nanostructured WO3 electrode is dark blue in color in the charged state and becomes transparent in its discharged state with a high optical modulation of 82%. The supercapacitor has a specific capacitance of 228 F g−1 at 0.25 Ag−1 with a large potential window (1.4 V). It is highly durable, exhibits good electrochemical stability over 2000 cycles, retains 75% of its initial capacitance, and exhibits high coloration efficiency (~170 cm2/C). The excellent electrochromic and electrochemical supercapacitor properties of the electrode is due to the synergetic effect between nanograin morphology and excess oxygen. A smart-supercapacitor fabricated with an oxygen-rich nanograin WO3 electrode exhibits a superb combination of energy storage and highly-efficient electrochromic features in one device that can monitor the energy storage level through visible changes in color.
Original language | English |
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Pages (from-to) | 78-85 |
Number of pages | 8 |
Journal | Solar Energy Materials and Solar Cells |
Volume | 166 |
DOIs | |
State | Published - 1 Jul 2017 |
Keywords
- Electrochromism
- Multi-functional electrode
- Nanograin
- Oxygen-excess tungsten oxide
- Supercapacitor