Synergy of W₁₈O₄₉ and Polyaniline for Smart Supercapacitor Electrode Integrated with Energy Level Indicating Functionality

Abstract

Supercapacitors are important energy storage technologies in fields such as fuel-efficient transport and renewable energy. State-of-the-art supercapacitors are capable of supplanting conventional batteries in real applications, and supercapacitors with novel features and functionalities have been sought for years. Herein, we report the realization of a new concept, a smart supercapacitor, which functions as a normal supercapacitor in energy storage and also communicates the level of stored energy through multiple-stage pattern indications integrated into the device. The metal-oxide W18O49 and polyaniline constitute the pattern and background, respectively. Both materials possess excellent electrochemical and electrochromic behaviors and operate in different potential windows, -0.5-0 V (W18O49) and 0-0.8 V (polyaniline). The intricate cooperation of the two materials enables the supercapacitor to work in a widened, 1.3 V window while displaying variations in color schemes depending on the level of energy storage. We believe that our success in integrating this new functionality into a supercapacitor may open the door to significant opportunities in the development of future supercapacitors with imaginative and humanization features.

Design Considerations for Unconventional Electrochemical Energy Storage Architectures

“…[ 230 ] A hybrid polymer (polyaniline) -transition metal oxide (W 18 O 49 ) has been also proposed recently with smart energy level indicating functionality (i.e., electrochromic response). [ 474 ] Nanostructured metallic oxides have been explored by Wei and Scherer for the realization of electrochromic ultracapacitors. [ 471,475 ] To increase the surface to volume ratio and enhance the ion-intercalation processes the authors used a self-assembled block-copolymer patterning approach to structure the V 2 O 5 and NiO active materials into ordered bicontinuous double-gyroid networks.…”

Deformable and Transparent Ionic and Electronic Conductors for Soft Energy Devices

“…[48] PANI is a widely used conducting polymer in electrochromism and supercapacitors. [205] It exhibits reversible color change from transparent to yellow-green and finally to dark blue-black from −0.2 to +1.0 V versus the saturated calomel electrode. [211] To fabricate stretchable transparent CNT-PANI composites, CVD synthesized CNT sheets were attached to the prestrained PDMS, followed by deposition of PANI through electropolymerization (Figure 14b).…”

“…[202] Moreover, electrochromic materials change their color reversibly by charge insertion/extraction or chemical reduction/oxidation, which is quite similar to the reaction kinetics of electrode materials in supercapacitors or batteries. [203] For this reason, bifunctional electrochromic supercapacitors [204][205][206] and batteries [207,208] have been demonstrated as smart energy devices with the function of presenting their charging states by color change. [209] Therefore, the strategies for STECs and STICs in stretchable transparent supercapacitors can be used to fabricate stretchable transparent electrochromic energy storage devices and electrochromic devices by incorporating electrochromic materials into STECs or STICs.…”

A Review of Metal Oxide Composite Electrode Materials for Electrochemical Capacitors

“…105 The study shows the speci¯c capacitance of 101 F/g and the excellent stability of this hybrid capacitor in concentrated H 2 SO 4 after 2600 cycles. Tian and co-workers 134 have reported a novel smart electrochemical capacitor which delivers new functionalities compared to conventional energy storage devices, employing W 18 O 49 and conducting polymer PANI as composite materials that is able to display multiple color change in response to varying levels of stored energy in aqueous solution of H 2 SO 4 . As can be …”

“…On contrary, the logo becomes blue in color on a transparent background as the electrochemical capacitor is discharged at À0:5 V. These additional features have brought an important breakthrough in next generation of energy storage technology. 134 …”