Electrochromic Battery Displays with Energy Retrieval Functions Using Solution‐Processable Colloidal Vanadium Oxide Nanoparticles

Abstract

for developing bistable displays due to their zero-energy consumption while maintaining a colored or colorless state. [3] However, operation of traditional electrochromic displays requires external voltages to trigger the coloration/bleaching processes, which makes the traditional electrochromic displays far from a netzero energy-consumption technology. The majority of the current electrochromic display research has focused on developing nanostructure electrochromic materials for fast switchings [4,5] without paying attention to how to reduce the consumed energy of the electrochromic displays.Recently, we developed a promising Zn-based electrochromic battery technology for smart windows. [6,7] The electrochromic battery exhibits self-coloration behaviors and eliminates the external voltage requirement for triggering the coloration process. The aqueous compatible Zn anode implements a much lower charged/bleached voltage for the electrochromic battery compared to the Li-and Al-based electrochromic batteries. [8][9][10] The lower charged/bleached potential indicates a lower energy consumption during the bleaching process. As such, the Zn-based aqueous electrochromic battery platform is an energy-efficient technology for reducing the energy consumption of electrochromic devices. To date, no reports exist on the utilization of electrochromic battery systems for developing energy-efficient electrochromic displays.Electrochromic materials play an important role in the development of electrochromic battery displays. Transition metal oxides (TMOs) have shown excellent electrochromic properties due to their remarkable multivalence states and the corresponding color evolutions. [11][12][13][14][15] Among the TMOs, vanadium oxide is considered the most promising material for electrochromic displays because of its multicolor behaviors. [16][17][18] However, the low electrical conductivity, significant volume expansion during cycling, and the slow reaction kinetics of bulk vanadium oxide prevent its widespread use. [19,20] In recent years, nanosized vanadium oxides have been studied to mediate these drawbacks because nanostructures provide abundant active sites on the surface and shorten the diffusion paths of ions. [20] Techniques, such as electrodeposition, [19] Electrochromic displays have attracted increased attention owing to their reversible switch of multicolors. However, the external voltage requirement for triggering the color switching makes them far from an optimum energyefficient technology. The newly developed electrochromic batteries eliminate the energy consumption for coloration while they can retrieve the consumed energy for bleaching. Such features make the electrochromic battery technology the most promising technology for energy-efficient electrochromic displays. Here, a scalable method to synthesize colloidal V 3 O 7 nanoparticles is presented, which is compatible with solution-process techniques for aqueous Zn-V 3 O 7 electrochromic battery displays. The Zn-V 3 O 7 electrochromic battery display shows an ...

Transparent Zinc‐Mesh Electrodes for Solar‐Charging Electrochromic Windows

“…A number of electrochromic materials, including the cathodic electrochromic materials (e.g., WO 3 , [13,16] Ti-substituted tungsten molybdenum oxide, [14] V 3 O 7 , [2] and sodium vanadium oxide [17] ) and anodic electrochromic materials (e.g., Prussian blue (PB) [15,18] ), have shown great compatibility to the newlydeveloped ZECDs. Due to the fact that the anodic tinting property enables the windows to be colored during the daytime, PB is considered to be the most promising electrochromic material candidate for solar-charging smart windows.…”

“…[40] Notwithstanding, the cycling durability of this ZECD smart window is comparable to the conventional state-of-the-art electrochromic windows/devices, [41] and ZECD electrochromic windows utilizing a Zn foil as an anode. [2,[13][14][15] Such better cycling durability is attributed to the fast switching times and the low leaching amount of Zn 2+ . The fast switching times reveal that the PB cathode only undergoes a slight structure deformation during cycling, while the low leaching amount of Zn 2+ eliminates the detrimental effect of high Zn 2+ concentration.…”

“…To shed light on the energy efficiency of the 80 cm 2 ZECD smart window during the solar charging and galvanostatic discharge processes, it is important to measure the roundtrip energy efficiency to determine the critical metric relevant to energy retrieval of the ZECD smart windows. [2,13,15] Figure 5. Solar-charging performance of the 80 cm 2 ZECD smart window.…”

Rechargeable Aqueous Zinc‐Ion Batteries with Mild Electrolytes: A Comprehensive Review

“…This device represents an emerging class of versatile electrochromic batteries (or energy storage smart windows), which can effectively increase the energy efficiency of buildings by means of light and electric energy management. [114][115][116] From quite different point of view, Yang et al [46] argue that the low utilization efficiency of C coordinated Fe (� CÀ Fe) should be an important reason for the poor rate performance and relatively low working voltage of Metal-HCFs. In the case of Na + storage in FeHCF,~68 % of the capacity attributes to the redox reaction of � NÀ Fe at~0.1 V vs. Ag/AgCl, while the residual capacity attributed to � CÀ Fe at~0.8 V. [117] Based on the above understanding, Yang et al, for the first time, established a high-voltage scanning strategy to activate � CÀ Fe and improve FeHCF's cycling stability and rate performance.…”

“…Mover, this group also developed a variety of electrochromic ZIBs. [114][115][116] Wen and Wu's group have also proposed a Zn 2 + /Al + dual-cation battery with a composite Al 2 (SO 4 ) 3 /Zn(CHCOO) 2 aqueous electrolyte, a Zn metal anode and an expanded graphite nano-sheet cathode . [139] To prepare the expanded graphite nano-sheets, a graphite/ NH 4 NO 3 /graphite symmetric cell was charged and discharged between 5 and À 5 V successively.…”