Reversible Metal Electrodeposition Research Articles

Design of a dynamically switchable metamaterial solar heating and daytime radiative cooling device based on reversible metal electrodeposition

Abstract The combination of daytime radiative cooling and solar heating can regulate the temperature of buildings in all seasons, which is vital to achieving energy savings. However, achieving a dynamic and efficient switch between radiative cooling and solar heating states is still challenging. The reversible metal electrodeposition is a promising electrochromic (EC) technology that can dynamically manipulate the visible and infrared spectrum by depositing a nanoscale metal layer. By combining it with a delicate nanostructure design, reconfigurable daytime radiative cooling and solar heating states can be achieved. In this work, a metamaterial EC device capable of efficiently switching between high solar reflectance (91.73%) and high solar absorptance (95.41%) via reversible silver layer electrodeposition has been developed. This device consists of a top layer, which is a visible transparent electrode of indium tin oxide covered with an ultrathin platinum film, an electrolyte in the middle, and a metamaterial absorber based on a metal/dielectric multilayered structure at the bottom. Afterward, we analyze the spectrum of each part of the device and carry out a parametric study on the practical performance with different ambient temperatures and convective heat transfer coefficients. The average solar reflectance of the device in the radiative cooling state is 93.41% within the range of 0.3–2.5 μm. In the solar heating mode, the average solar absorptance of the device reaches 95.46%. Numerical simulations show that the device in the cooling mode achieves a temperature drop of 5 °C–9.8 °C and an average cooling power of 140.8 W m − 2 . The device in heating mode achieves a maximum temperature rise of 45 °C and a maximum heating power of 700 W m − 2 . This work provides a feasible design for solar heating and daytime radiative cooling switching devices, which is promising in applications like energy-saving buildings, wearable devices, electric vehicles and other outdoors facilities.

Reversible Nickel Electrodeposition Electrolytes for Dynamic Window Applications

Amid the energy crisis, reducing energy consumption has become a growing field of energy research. When analyzing energy usage, buildings are responsible for 30% of global energy consumption.1 One of the ways to reduce this enormous energy consumption in buildings is to reduce the amount of heating, cooling, and air conditioning needed to provide comfortable work and living spaces. In this regard, dynamic windows are an innovative approach to increasing building energy efficiency as they electronically switch between light and dark states.2 By controlling the transparency of the window, dynamic windows help control the temperature of a space and, therefore, save on average 10% of energy consumption in buildings.3 Reversible metal electrodeposition (RME) provides a method of constructing dynamic windows that possess color neutrality, high switching speed between dark and light states, low cost, and durability over thousands of cycles.4 In recent years, zinc has emerged as a standout metal for application in dynamic windows.2,5 However, the interactions of the deposited zinc film with the surrounding water in the aqueous electrolytes can slowly deteriorate device performance.6 To ameliorate the situation, we are developing dynamic windows with nonaqueous nickel electrolytes, which have many of the advantageous properties of typical RME dynamic windows, but are more robust than analogous zinc systems.

Adaptive infrared radiation modulator using reversible metal electrodeposition with silicon carbide-based fabry-perot cavity

Conventional materials that statically modulate radiation in the infrared (IR) region of the electromagnetic spectrum underpin the performance of many entrenched technologies. The development of their adaptive variants, whereby the IR radiation properties dynamically change as a response to external stimuli, has emerged as an important unfulfilled scientific challenge. Here, by combining the silicon carbide (SiC)-based Fabry-Perot (FP) cavity effect with the traditional reversible metal electrodeposition device (RMED), where the FP cavity is used as a color filter to emit a particular wavelength and the RMED is used to reversibly modulate IR radiation, we develop an adaptive IR radiation modulator with large and uniform IR emissivity tunability (Δε ≥ 0.579) in the 3–14 µm region. A specific structural color which is a function of the SiC thickness can be simultaneously displayed when the modulator is in the low-emissivity mode. By varying the SiC thickness from 100 to 180 nm, a full gamut of colors spanning the entire visible spectrum can be achieved. Additionally, the modulator can exhibit fantastic patterns consisting of different structural colors with simple designs achieved. We believe that our findings may open opportunities for camouflage in multispectral detection and many technologies related to IR radiation management.

Recent Developments of Next-generation Smart Window using Metal Electrodeposition

Due to the energy and environmental crisis, indoor energy efficiency is of great importance. One of the solutions to cope with the problem is adopting a device with energy-saving functionality. From that perspective, smart window technology has received the foremost attention as of great potential, because it could modulate the solar energy stream such as light and heat. In addition to that, smart windows could offer visual aesthetic operation to our daily lives. Despite many technical attempts, no technology has been commercialized abruptly due to the restrictions or disadvantages. One of the rising options is a smart window based on reversible metal electrodeposition, as metal electrodeposits possess high contrast with color neutrality, and high coloration efficiency for privacy state. Since 2017, reversible metal electrodeposition-based smart window technology has been emerging, and advancing in terms of cycling, bistability, and color uniformity. This review aims to summarize the current technological trends and directions for the development of reversible metal electrodeposition-based smart window technologies.

Electrolyte design for zinc dynamic windows with fast switching that cycle more than 11,000 times with high optical contrast

The widespread adoption of electronically adjustable dynamic windows promises to significantly improve the energy efficiency of buildings. In this manuscript, we develop robust dynamic windows based on the reversible metal electrodeposition (RME) of Zn from DMSO electrolytes. We systematically interrogate the role of anions, cations, and polymer additives on electrolyte properties and develop design rules to increase the electrochemical and optical reversibility of these systems. This fundamental understanding allows us to develop an electrolyte that facilitates reversible Zn electrodeposition with unprecedented speed and reversibility with a Coulombic efficiency of 99.5%. We implement this electrolyte into practical two-electrode 25 cm2 dynamic windows and demonstrate that these devices switch more than 11,000 times without degradation in optical performance and without altering the switching speed or voltage profile. This outstanding durability is unprecedented in the field of RME windows and brings metal-based dynamic windows substantially closer to successful commercialization.

Refractive Index Modulation for Metal Electrodeposition-Based Active Smart Window Applications.

One of the remarkable choices for active smart window technology is adopting a metal active layer via reversible metal electrodeposition (RME). As the metal layer efficiently blocks the solar energy gain, even a hundred-nanometer-thick scale, RME-based smart window has great attention. Recent developments are mainly focused on the various cases of electrolyte components and composition meeting technological standards. As metal nanostructures formed through the RME process involve plasmonic phenomena, advanced analysis, including plasmonic optics, which is beyond Beer-Lambert's law, should be considered. However, as there is a lack of debates on the plasmonic optics applied to RME smart window technology, as research is mainly conducted through an exhaustive process. In this paper, in order to provide insight into the RME-based smart window development and alleviate the unclear part of plasmonic optics applied to the field, finite-difference time-domain electromagnetic simulations are conducted. In total, two extremely low-quality (Cr) and high-quality (Mg) plasmonic materials based on a nanoparticle array are considered as a metal medium. In addition, optical effects caused by the metal active layer, electrolyte, and nanoparticle embedment are investigated in detail. Overall simulations suggest that the effective refractive index is a decisive factor in the performance of RME-based smart windows.

Tunable Microwave Absorbing Devices Enabled by Reversible Metal Electrodeposition.

Tunable microwave absorbers have gained significant interest due to their capability to actively control microwaves. However, the existing architecture-change-based approach lacks flexibility, and the active-element-based approach is constrained by a narrowband operation or small dynamic modulation range. Here, a novel electrically tunable microwave absorbing device (TMAD) is demonstrated that can achieve dynamic tuning of the average reflection amplitude between -13.0 and -1.2 dB over a broadband range of 8-18 GHz enabled by reversible metal electrodeposition. This reversible tunability is achieved by electrodepositing silver (Ag) layers with controlled morphology on nanoscopic platinum (Pt) films in a device structure similar to a tunable Salisbury screen, employing Ag electrodeposited on Pt films as the modifiable resistive layer. Furthermore, this TMAD possesses a simple device architecture, excellent bistability, and multispectral compatibility. Our approach offers a new strategy for dynamically manipulating microwaves, which has potential utility in intelligent camouflage and communication systems.

Electrolyte design for reversible metal electrodeposition-based electrochromic energy-saving devices

Reversible metal electrodeposition (RME)-based electrochromic devices have been attracting significant research interest due to their merits of low cost, simple configuration, and high extinction coefficients. As the key component in the electrochromic system, RME electrolytes with various metal ions and additives have endowed the RME device with flexible functionalities in energy-saving applications such as energy-efficient displays, smart windows, and camouflages. However, it is still challenging to research a widespread commercial application before some critical issues can be solved such as poor reversibility, low optical memory of the mirror state, and slow switching speed. Here, we offer a critical review of the recent progress of RME electrochromic devices based on aqueous, organic, ionic liquid, and eutectic electrolytes. Furthermore, the main challenges and perspectives for RME electrolytes are highlighted and discussed.

Pulsed electrodeposition for dynamic windows based on reversible metal electrodeposition

Pulsed electrodeposition for dynamic windows based on reversible metal electrodeposition

Dynamic smart window over the entire solar spectrum using a dry deposited device for sustainable architecture

We developed a dynamic smart window capable of demonstrating transparent, black, and mirror modes across the entire solar spectrum. We demonstrated that the surface-roughness-controlled WO3 film deposited by nano particle deposition system (NPDS) can achieve the black mode with almost zero solar heat transmittance (Tsol). In the Reversible Metal Electrodeposition (RME), device can block heat similar to the mirror mode. NPDS is a unique dry deposition method to enhance the light scattering effect. As a result, the transmittance was measured in the range of the entire solar spectrum (λ ∼ 300 nm–2500 nm), obtaining 0.81% and 0.56% of Tsol for the black and mirror modes, respectively. However, 61% of Tsol was obtained for the transparent mode, confirming stark differences in Tsol. Furthermore, a dynamic smart window of 4 cm2 in size was fabricated to study the temperature change within the model house upon exposure to an infrared lamp to monitor any increase in temperature during transparent, black, and mirror modes. As a result, the temperature increases within the model house during transmittance mode increased by 19.2 °C, while the temperature increases during black and mirror modes slightly by 4.1 °C and 3.8 °C, respectively. The dynamic smart window was able to reduce the indoor temperature by more than 4.7 folds during the black/mirror modes. These findings confirmed that we developed an RME device capable of completely blocking sunlight to minimize indoor temperature change across the entire solar spectrum.

The Progress and Outlook of Multivalent‐Ion‐Based Electrochromism

Electrochromic technology has witnessed numerous achievements in recent years both in research and commercialization. Electrochromic devices (ECD) based on different electrochemical mechanism have been developed for various applications, ranging from smart windows, thermal management, rear views, display, camouflage, etc. Compared to conventional ECDs based on monovalent charge carriers (e.g., H+, Li+), incorporating multivalent ions with rich electrochemistry, high charge density, and small ionic radius has opened new possibilities in novel ECDs. The merits of multivalent ions are harvested in ECDs activated by ion intercalation/deintercalation (e.g., Zn2+, Al3+, Ca2+, Mg2+), reversible metal electrodeposition (e.g., Cu2+, Bi3+, Zn2+), and dynamic metal–ligand interactions (e.g., Cu2+, Fe2+). Herein, the working mechanism, characteristics, and up‐to‐date achievements in multivalent ECDs are summarized and classified accordingly. The applications of multivalent ECDs for smart windows, energy storage, thermal management, multicolor displays, etc., are exemplified. The issues and challenges encountered by multivalent ECDs are emphasized, and the future directions for developing multivalent ECDs are also summarized. The aim of this review is to inspire more efforts in the exploration and the proliferation of multivalent ECDs.

Origin of high optical contrast in zinc-zinc oxide electrodeposits for dynamic windows

The control of solar light and heat emission through windows is an important strategy for increasing the energy efficiency of buildings. Reversible Zn electrodeposition has recently emerged as a promising method for constructing electronically tintable robust dynamic windows. In Zn electrodeposits formed from dimethyl sulfoxide (DMSO) electrolytes during device tinting, we observe extraordinary absorption that is in excess of what is predicted by the Beer-Lambert law for a uniform Zn thin film. The charge required to electroplate these films is abnormally low, significantly less than previously reported dynamic windows based on reversible metal electrodeposition, which facilitates the construction of large-area devices that switch uniformly. Finite-difference time-domain (FDTD) simulations are used to investigate the origin of this enhanced absorption, which arises from plasmonic effects among the Zn nanoparticles and ZnO dendrites in the film. The dielectric ZnO dendrites promote absorption via slit-like Zn-dielectric-Zn structures that from hybrid surface plasmon resonance at metal walls. Through these investigations, we provide design principles to construct low-charge and high-contrast metal and metal oxide-based dynamic windows.

Bi-Cu Electrolytes with Aminocarboxylate Chelators for Reversible Metal Electrodeposition at High pH for Dynamic Windows

Dynamic windows, which possess electronically tunable light transmission, increase both the energy efficiency and aesthetics of spaces such as buildings and automobiles. Although reversible metal electrodeposition affords a promising approach to constructing high-performing dynamic windows, the acidic nature of the aqueous electrolytes frequently used in these windows has prevented their commercialization due to tin-doped indium oxide (ITO) etching. In this manuscript, we design neutral and alkaline electrolytes that support the reversible electrodeposition of Bi and Cu at rates comparable to existing acidic electrolytes. In these electrolytes, Bi3+ and Cu2+ are solubilized by using aminocarboxylate chelating ligands. By evaluating a series of ligands with varying denticities, we demonstrate that N-(2-hydroxyethyl)ethylenedianmine-N,N’,N’-triacetic acid (ED3A-OH) provides the optimal metal ion binding strength that enhances solubility while simultaneously supporting rapid metal electrodeposition. These results allow us to design alkaline ED3A-OH electrolytes that are compatible with ITO even after four weeks of immersion at 85 °C. This manuscript thus demonstrates that chelating ligands can be utilized to design alkaline reversible metal electrodeposition electrolytes that support dynamic windows with robust shelf lives.

Gel polymer electrolyte for reversible metal electrodeposition dynamic windows enables dual-working electrodes for faster switching and reflectivity control

Dynamic windows based on reversible metal electrodeposition are an attractive way to enhance the energy efficiency of buildings and show great commercial potential. Dynamic windows that rely on liquid electrolytes are at risk of short circuiting when two electrodes contact, especially at larger-scale. Here we developed a poly (vinyl alcohol) (PVA) gel polymer electrolyte (GPE) with 85% transmittance, that is, sufficiently stiff to act as a separator. The GPE is implemented into windows that exhibit comparable electrochemical and optical properties to windows using a liquid electrolyte. Furthermore, the GPE enables the fabrication of windows with dual-working electrodes (WE) and a metal mesh counter electrode in the center without short-circuiting. Our dual-WE PVA GPE window reaches the 0.1% transmittance state in 101 s, more than twice the speed of liquid windows with one working electrode (207 s). Additionally, each side of the dual-WE GPE window can be tinted individually to demonstrate varied optical effects (i.e., more reflective, or more absorptive), providing users and intelligent building systems with greater control over the appearance and performance of the windows in a single device architecture.

Understanding and Improving Mechanical Stability in Electrodeposited Cu and Bi for Dynamic Windows Based on Reversible Metal Electrodeposition

AbstractDynamic windows based on reversible metal electrodeposition (RME) can electronically adjust light transmission from ≈70% to <0.1% to improve building aesthetics and energy efficiency by controlling light and heat flow. For RME devices using Cu and Bi, the windows reach “privacy state” (<0.1% transmission) when ≈180 nm of metal is electrodeposited on the transparent conducting electrode. When films with a plated atomic Cu–Bi ratio of ≈2:1 rest in the privacy state, sinusoidal cracks form across the entire film, and the metal delaminates in <1 day. This mechanical failure renders the window unusable as specks of metal are visually unattractive and reduce the dynamic range of the window. The Cu–Bi film is stress free upon deposition, but after 4 h of resting, 38 MPa of tensile stress develops. The tension in Cu–Bi and Cu films combined with the Cu(ClO4)2in the electrolyte results in severe, widespread fractures and delamination due to stress corrosion cracking. In contrast, electrodeposited Bi films have compressive stress, likely due to high self‐diffusion and insertion of atoms into grain boundaries while plating, which results in a Bi‐based dynamic window with crack‐free resting stability that exceeds 9 weeks.

Investigating Formate, Sulfate, and Halide Anions in Reversible Zinc Electrodeposition Dynamic Windows.

Reversible metal electrodeposition (RME) is an emerging and promising method for designing dynamic windows with electrically controllable transmission, excellent color neutrality, and wide dynamic range. Zn is a viable option for metal-based dynamic windows due to its fast switching kinetics and reversibility despite its very negative deposition voltage. In this manuscript, we study the effect of the supporting electrolyte anions for Zn electrodeposition on transparent tin-doped indium oxide. Through systematic additions or removal of components of the electrolytes, we are able to establish a link between the anions and the effectiveness of Zn RME. This insight allows us to design practical two-electrode 25 cm2 Zn dynamic windows that switch to <1% within 20 s. Lastly, we demonstrate that the accumulation of Zn(OH)2 species on the working electrode degrades the optical contrast of Zn windows during long-term cycling. However, the elimination of these species through acid immersion allows the windows to cycle at least 500 times. Reversible Zn electrodeposition in the presence of a polyethylene glycol additive further improves the cycle life to greater than 1000 cycles. Taken together, these studies highlight important design principles for the construction of robust dynamic windows based on Zn RME.

Constructing low N/P ratio sodium-based batteries by reversible Na metal electrodeposition on sodiophilic zinc-metal-decorated hard carbons

Nowadays, the main deficiency in boosting the commercialization of sodium ion battery is the relatively low energy density. Herein, we propose a new way to significantly improve the energy density by constructing low negative/positive (N/P) ratio sodium-based batteries enabled by reversible Na metal electrodeposition on sodiophilic zinc-metal-decorated hard carbons (HC–Zn) anode. HC-Zn is used as a typical insertion anode, and simultaneously as a substrate for Na metal plating, leading to the formation of a composite NaxC-Na metal anode with a hybrid energy storage process. We also provide a general and low-cost method of Zn metal coating on various hard carbons. The compatibility between Zn and Na metal is firstly revealed by molecular dynamics simulations. As a result, HC-Zn electrode exhibits a highly reversibility even at a high-capacity of 1100 mA h g−1 and 5C rate, which can stably cycle 1400 cycles with a high Coulombic efficiency around 100%. Finally, the full cells of HC-Zn anode coupling with sodium vanadyl phosphate cathode with low NP ratio (NP = 0.8 and 0.6) are constructed which display good cycling stability and remarkably improved energy density from 220 Wh/kg of regular NP 1.1 to 286 Wh/kg.

Transparent, High‐Charge Capacity Metal Mesh Electrode for Reversible Metal Electrodeposition Dynamic Windows with Dark‐State Transmission &lt;0.1% (Adv. Energy Mater. 32/2022)

Dynamic Windows In article number 2200854, Michael D. McGehee and co-workers discuss the metal mesh electrode design principles for dynamic windows based on reversible metal electrodeposition that electronically tint from a clear state to a color-neutral privacy state (<0.1% transmission). A durable design is developed using an inert core (stainless steel), a thin electrodeposited Au layer, then an electrodeposited Cu-Bi outer layer. Cover designed by Ehsan Faridi and Ehsan Keshavarzi - Inmywork Studio.

Metal Mesh Design for Dynamic Windows Based on Reversible Metal Electrodeposition

Dynamic windows, which allow electronic control over visible light and solar irradiation, enable responsive environments free of glare and unwanted heat. Electronic control over visible light transmittance and solar heat gain coefficients will allow dynamic windows to be integrated with algorithms to optimize for energy efficiency and comfort. The implementation of this technology increases building energy efficiency by up to 20% compared to traditional, static low-emissivity windows.[ 1] Furthermore, worker productivity can be increased by 2% due to reductions in eye strain, headaches, and drowsiness.[ 2] Dynamic windows based on reversible metal electrodeposition (RME) represent an exciting, new class of electrochromic devices. These RME windows function like a battery by electrochemical movement of metallic ions dissolved in a nearly colorless aqueous electrolyte between a transparent conducting working electrode and a metal mesh or ion-intercalation counter electrode (see Figure). Metals are ideal light-modulators for dynamic windows because they can be color neutral, inert, photostable, and opaque at 20-30 nanometer thicknesses. Our team has most recently demonstrated metal-based dynamic windows that boast a dark state below 0.001% visible light transmittance in less than 10 minutes, an ultrawide range for optical and solar modulation (ΔTvis=0.76 and ΔSHGC=0.56) with uniform and color neutral (C*<5) tinting in prototypes >900 sq. cm.[ 3] To achieve a dark state transmission <0.1%, which has been defined as privacy state, ~150 mC/sq. cm of charge must be shuttled between the working electrode and counter electrode. We first outline the counter electrode design parameters for these high-contrast RME dynamic windows: high transparency, capacity, and surface area while maintaining low haze, sheet resistance, and cost. We show that metal meshes are a leading candidate for the counter electrode material based on these design parameters. Metal meshes also keep the design simple by having the same reversible electrochemical reaction on both electrodes (in opposite directions).We then analyze the material composition of the metal mesh to ensure cycling durability in a Cu-Bi electrolyte. This analysis shows that previously used Cu mesh in as the counter electrode material increases [Cu2+] over cycling (~200 privacy cycles) which results in degradation optically and electrochemically. We then develop a transparent mesh using an inert core with a thin metal coating that enables a high capacity (1.5 C/sq. cm) Cu-Bi layer for a metal mesh counter electrode. Finally, we incorporate this custom designed mesh in an RME dynamic window and demonstrate 250 privacy cycles.Developing a strong understanding of reversibly electroplating metals using multivalent metallic ions with variable sizes yields valuable insight to batteries where reversible plating is critical for operation and durability, particularly with deep cycling.

Design of a widely adjustable electrochromic device based on the reversible metal electrodeposition of Ag nanocylinders

Design of a widely adjustable electrochromic device based on the reversible metal electrodeposition of Ag nanocylinders