High performance in electrochromic amorphous WOx film with long-term stability and tunable switching times via Al/Li-ions intercalation/deintercalation.

Lithium ion (Li+) aggregation in the amorphous tungsten oxide (a-WO x) film is the main cause of the electrochromic (EC) device failure. This has hindered a-WO x films goes towards industrialization on behalf of the giant EC performance and long-term reliability. A novel kind of electrolytes consisted of Aluminum ions (Al3+) and Lithium ions (Li+) used for electrochromic sputtered a-WO x films is presented. With the newly designed Al3+/Li+ co-existed electrolytes, the optical transmittance modulation can be largely enhanced compared with Li+, meanwhile, the problem of degradation after long-term cycling for a-WO x induced by Li ions-trapping is able to be solved. Furthermore, the utilization of Al3+ brings slow switching kinetics at the ions extraction step to the films compared with Li+, which supplies a new method to modulate the bleaching rate by applying adjustable Al3+/Li+ ratio of electrolytes and a tunable and controllable switching time is easily achieved in this work. This Al3+/Li+ co-based electrolyte opens a new way to design and control the high contrast, long-lived cycling stability and changeable switching time EC devices based on a-WO x films. [ABSTRACT FROM AUTHOR]