Transparent metal oxide interlayer enabling durable and fast-switching zinc anode-based electrochromic devices

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Growing energy and environmental concerns necessitate advanced multifunctional devices.
• Electrochromic devices (ECDs) show promise for dual-functional electrochromic-energy storage (ECES) applications due to their similarity to secondary batteries.
• Prussian blue (PB) is a common electrochromic material for ECES devices but suffers from poor stability and limited capacity.

Purpose of the Study:

• To enhance the structural stability and capacity of Prussian blue (PB) for electrochromic energy storage (ECES) devices.
• To improve the optical modulation and switching kinetics of PB-based ECES devices.
• To develop a novel transparent metal oxide interlayer for advanced ECES applications.

Main Methods:

• Incorporation of a transparent nickel oxide (NiO) nanosheet interlayer into Prussian blue (PB) films.
• Fabrication and characterization of NiO/PB nanocomposite films.
• Assembly and testing of a prototype zinc anode-based electrochromic device using the NiO/PB film.

Main Results:

• The NiO/PB nanocomposite film demonstrated a high areal capacity (50 mA h m⁻²) and excellent electrochemical stability.
• The NiO/PB film achieved a large optical modulation (73.2%), fast switching times (1.4 s color, 2.6 s bleach), and high coloration efficiency (54.9 cm² C⁻¹).
• A prototype device showed self-bleaching capability and retained 92% optical modulation after 1000 cycles, with a large-area demonstration (100 cm²).

Conclusions:

• The transparent NiO interlayer effectively enhances the performance and durability of PB-based ECES devices.
• The developed NiO/PB nanocomposite offers a promising pathway for constructing high-performance, dual-functional electrochromic energy storage devices.
• This approach provides a foundation for designing novel multifunctional ECES devices with improved stability and kinetics.