Mo addition for improved electrochromic properties of V2O5 thick films

Abstract

Transition metal oxides (TMOs) have attracted considerable attention due to their variety of chromogenic properties. Among them, vanadium pentoxide (V2O5) has gained significant interest in respect of multichromism associated with orange, green and blue colors. Herein, we report a simple and easy method for the fabrication of Mo doped V2O5 thick films, leading to improved cyclability. Molybdenum doped vanadium pentoxide powders were synthesized from one single polyol route through the precipitation of an intermediate precursor: molybdenum doped vanadium ethyleneglycolate (Mo doped VEG). The as-synthesized Mo-doped V2O5 exhibits improved electrochromic performance in terms of capacity, cycling stability, and color contrast compared to single-component V2O5 in lithium as well as sodium based electrolyte. The improvement in EC performances lies in films of higher porosity as well as higher diffusion coefficients. To conclude, an electrochromic device combining Mo-V2O5 to WO3.2H2O, via a PMMA-lithium based electrolyte membrane exhibit simultaneously reversible color change from yellow to green for Mo-V2O5 and from blue to yellow white for WO3.2H2O with a cycling stability up to 10 000 cycles.

Towards enhanced durability of electrochromic WO3 interfaced with liquid or ceramic sodium-based electrolytes

“…The simplest case consisting of an aqueous sodium-based electrolyte is limited up to 20 coloration-bleaching switches with CE falling from~90 % at 20 cycles down to 70 % at 100 cycles. This behavior can be improved with the use of a ion-conducting solid cap (CE~90 %) or with an ionic liquid sodium-based [18,25]. Moreover, this study underlines that the degradation of WO 3 cannot be neglected and leads to wrong evaluation of its electrochromic performance in aqueous medium.…”

“…Therefore, the development of EC devices based upon Na-intercalated WO 3 should not be overlooked before detailed investigation is conducted. If WO 3 can readily operate a sodiation-desodiation process using typical three electrodes configuration in aqueous [19][20][21] or non-aqueous [22][23][24][25] electrochemistry, investigations on how to handle the degradation of the amorphous tungsten oxide under potentiodynamic conditions in an aqueous Na + -based medium are lacking. Actually, the degradation in the amorphous case has been suggested [26,27] as originating from very open microstructure with the formation of alkali metatungstate.…”

A Systematic Review of the Most Recent Concepts in Smart Windows Technologies with a Focus on Electrochromics

“…The characteristic feature of vanadium oxide is the existence of several oxidation states that offer the possibility of creating multicolour EC windows/displays. The papers on the electrochromic properties of V 2 O 5 were recently published by Chu et al [64] and Mjejri et al [65].…”

The study of activation impact during formation and testing of Ni(OH)2 electrochromic films in the presence of Al3+ and WO42- ions

“…Among electrochromic materials, there are organic [11,12] and inorganic materials [13,14]. Organic materials include some polymers: polyaniline, polypyrrole, polythiophenes and metal polymers.…”