Towards a thin films electrochromic device using NASICON electrolyte

Abstract

The optimisation of the morphology of WO 3 thin films allowed a more efficient electrochromic colouring using Na + ions than H + ones. Therefore, sodium superionic conductor (Na 3 Zr 2 Si 2 PO 12 , NASICON) films may be used as electrolyte in inorganic electrochromic devices. In this paper, the structure, chemical composition, morphology and electrochromic properties of WO 3 , ZnO:Al and Na 3 Zr 2-Si 2 PO 12 thin films were studied to develop a novel type of electrochromic device. WO 3 , ZnO:Al and Na 3 Zr 2 Si 2 PO 12 thin films were deposited using reactive magnetron sputtering of tungsten, zinc and aluminium and Zr-Si and Na 3 PO 4 targets, respectively. For transparent conductive oxide coatings, a correlation was established between the deposition parametres and the film's structure, transmittance and electrical resistivity. Classical sputtering methods were not suitable for the deposition of NASICON films on large surface with homogenous composition. On the other hand, the use of high-frequency pulsed direct current generators allowed the deposition of amorphous films that crystallised after thermal annealing upon 700°C in the Na 3 Zr 2 Si 2 PO 12 structure. Amorphous films exhibited ionic conductivity close to 2×10 −3 S cm −1 . Finally, preliminary results related to the electrochromic performance of NASICON, WO 3 and indium tin oxide devices were given.

Atomic Layer Deposition of Sodium Phosphorus Oxynitride: A Conformal Solid-State Sodium-Ion Conductor

“…to confirm the film stoichiometry, thus preventing a direct comparison. Sputtered NASICON (Na 3 Zr 2 Si 2 PO 4 ) has been reported for applications in CO 2 sensors and electrochromic devices. , Horwat et al reported a room-temperature ionic conductivity of 3.1 × 10 –5 S/cm for amorphous as-deposited films (1000 nm). Bang et al reported an ionic conductivity of 0.29 S/cm at 200 °C with an activation energy of 0.55 eV for an annealed crystalline NASICON film (2000–2500 nm).…”

“…A polymer electrolyte film (100–200 μm) was shown to enable a solid-state SIB, but its thickness and organic nature prevent direct comparison to an inorganic thin-film SSE. Additionally, it was only demonstrated that thin-film solid Na + conductors were deposited by magnetron RF sputtering, − which require large thicknesses (>1000 nm) and are not compatible with 3D high-aspect-ratio structures. For the realization of next-generation SIBs, further research attention is required on the development of thin-film Na-ion conductors.…”

Electrochromic and magnetic ionic liquids

“…6 The conducting surfaces are covered by the electrochromic material, consisting of chemicals capable of forming an electrochromic layer due to a strong colour contrast upon oxidation/reduction. Preparation of a high ionic conductive electrolyte 7 is generally the most challenging component of these devices. Ionic liquids (ILs) 8 are known to have some of the properties required for a good electrolyte: high ionic conductivity, large electrochemical windows, 9 excellent thermal and chemical stability and in addition they exhibit a negligible vapour pressure 10 and ability to solubilize organic, inorganic and polymeric materials.…”

Toward Next‐Generation Smart Windows: An In‐depth Analysis of Dual‐Band Electrochromic Materials and Devices

“…Moreover, there's an escalating interest in pioneering novel electrolytes. These innovations, including Al 3+ -based, [11,12,94] Zn 2+ -based, [95][96][97][98][99] and Na + -based electrolytes, [100,101] not only offer potential enhancements to dual-band electrochromic performance but also present an avenue to circumvent the challenges associated with costly lithium ore and detrimental acid corrosion.…”