Three‐dimensional knotting of W₁₇O₄₇@PEDOT:PSS nanowires enables high‐performance flexible cathode for dual‐functional electrochromic and electrochemical device

Abstract

An efficient integration of electrochromic and electrochemical devices into one flexible entity enables both energy storage and energy-saving dual-functionalities.For this purpose, achieving both high electrochromic and electrochemical performance is the key aspect. Herein, a new 3D architecture is successfully made by knotting W 17 O 47 @PEDOT (poly(3,4-ethylenedioxythiophene)):PSS (poly (styrenesulfonate)) nanowires with NaWO 3 nanoknots, and interestingly, the 3D W 17 O 47 /(NaWO 3 -knots)@PEDOT:PSS cathode thus-made simultaneously exhibits a large optical modulation (79.7% at 633 nm), an ultra-long cycling life (76% of original optical modulation retained after 12 400 cycles), and a high areal capacitance (55.1 mF cm À2 at 0.1 mA cm À2 ). Our density functional theory (DFT) calculations demonstrate that the much improved dual-functional performance is correlated to the raised electronic conductivity and ion adsorption at the W 17 O 47 / (NaWO 3 nanoknots) interface, together with the ion adsorption of PEDOT:PSS in the 3D-knotted architecture. As a proof-of-concept application, different-sized flexible dual-functional electrochromic/electrochemical devices (FDEDs) were assembled and investigated for various application scenarios, including a smart window (15 cm  10 cm), a wearable wristband (20 cm  2.5 cm), and a smart eyeglass.The smart window made of the FDED enables a large temperature difference of 27.6 C confirm-tested in model houses, where the energy source also powers three light-emitting diodes (LEDs). The understandings of the key governing principles in the electrodes and dual-functionalities provide a timely foundation for the new generation flexible multifunctional devices.

Rapidly Photocurable Solid‐State Poly(ionic liquid) Ionogels For Thermally Robust and Flexible Electrochromic Devices

“…To counteract the rather sluggish kinetics of WO 3 in solid state electrolyte, a thin layer of PEDOT:PSS has been coated onto WO 3 (denoted as P-WO 3 ) to promote electron transportation as suggested in previous studies. [52][53][54] On the counter electrode, non-electrochromic TiO 2 nanoparticles, which are known to lower working voltage and prolong cycling stability, were adopted as the charge-balancing layer (Figure S9, Supporting Information). [55] In this study, sandwich ECDs were fabricated through a combination of self-wetting process and in situ photo polymerization (Figure 3a).…”

Electrochromic-Induced Rechargeable Aqueous Batteries: An Integrated Multifunctional System for Cross-Domain Applications

“…In concept, MERABs are designed to integrate electrochromic and aqueous batteries into one entity with the expectation of executing multiple tasks simultaneously [ 43 ]. With this objective, MERABs have brought an emerging and profound understanding of design principles and operating mechanisms, together with the progress in targeted interdisciplinary applications (Fig.…”

“…However, a slow switching speed and limited color-tuning versatility are two main challenges faced for such EBMs because of the poor electronic conductivity and structural flexibility. Over the past couple of decades, three main strategies have been proposed to address these problems.i ) Size effect: ranging from zero-dimensional dots to one-dimensional nanowires/rods, two-dimensional nanosheets, and three-dimensional (3D) hierarchical structures [ 4 , 21 , 43 , 49 , 50 ]. Quantum dots (QDs) with ultra-small sizes can be used to harvest vigorous quantum confinement effect and greatly decrease the interfacial diffusion barrier for ions.…”

Amorphous and Porous Tungsten Oxide Films for Fast‐Switching Dual‐Band Electrochromic Smart Windows

“…[ 1,2 ] Hence, it is imperative to develop energy‐efficient widows to improve the energy efficiency of buildings. [ 3–24 ] Dual‐band electrochromic smart windows capable of the spectrally selective modulation of visible (VIS) light and near‐infrared (NIR), [ 25–30 ] as a recent energy‐efficient technology, can significantly lower the building energy consumption in lighting, heating, and cooling through the smart regulation of solar light and solar heat into the buildings. [ 31–37 ] They can also provide the occupants with increased visibility and thermal comfort to improve their health, happiness, and productivity.…”