Electrochromic Device Based On Vanadium Oxide Active Electrode And Salt-based Electrolyte

Category- Advance Materials & Manufacturing/ Electronics & Circuits

Industry:

Manufacture of electronic displays, Flat glass manufacturing; Semiconductor and Related Device Manufacturing.

Applications:

Smart windows; Variable-reflectance mirrors; Electrochromic displays; Low-power optical shutters; Light modulators.

Market report:

The global electrochromic devices market was valued at USD 2.26 billion in 2023, projected to grow to USD 9.5 billion by 2035 with a CAGR of 12.71 %

Electrochromic devices with applications in smart windows, optical displays, and e-papers, enhance energy efficiency and sustainability by significantly reducing energy consumption.
Traditional transition metal oxides, such as tungsten oxide and nickel oxide are used in electrochromic devices for their stability and optical properties. Further, Lithium-based electrolytes dominate the market due to their efficiency; however, these face safety and cost challenges.
Conventional technologies also use corrosive and hazardous electrolytes while having high fabrication costs, and limited cyclic stability due to structural degradation.
There is need for eco-friendly, cost-effective, and safer films and electrolytes that exhibit superior cyclic stability, faster switching times, and multicolor electrochromism.

V₂O₅ thin films (~80 nm) are grown by DC reactive magnetron sputtering at 150 °C, then vacuum-annealed at 400 °C to induce orthorhombic crystallinity and surface roughness (~19.5 nm)
Neutral aqueous electrolytes (1 M NaCl, KCl, CaCl₂) intercalate monovalent/divalent cations; CaCl₂ offers widest potential window, highest ionic conductivity, and best cyclic stability
At 633 nm, films in CaCl₂ deliver ∆T ≈ 36.6 %, coloration efficiency η ≈ 36.6 cm² C⁻¹, response times 8.03 s (colour) and 5.51 s (bleach), operating between –0.25 V and +0.73 V
A 2×2 cm² solid-state EC cell uses V₂O₅/FTO cathode, PVA/CaCl₂ gel electrolyte, and FTO counter-electrode, switching reliably at ±1.8 V for > 1 000 cycles with minimal degradation
Compact, low-voltage, all-solid-state design with non-toxic components and facile sputtering/annealing process underpins scalable production for smart glazing and displays.

Utilizes salt-based electrolytes (e.g., CaCl2) instead of hazardous lithium-based ones, addressing safety and environmental concerns.
Enables transitions between yellow, green, and grey states, unlike traditional devices limited to monochromatic shifts.
Operates efficiently at ±2.5 V, reducing energy consumption compared to other electrochromic technologies.
Exhibits superior cyclic performance, maintaining stability over 1000 cycles, reducing maintenance and replacement costs.
Employs straightforward sputtering techniques with affordable materials, enabling scalability for commercial applications.

Prof. Parasuraman Swaminathan

Department of Metallurgical and Materials Engineering

TRL 4

Technology Validated in Lab

Technology Transfer