Effect of independently controllable electrolyte ion content on the performance of all-solid-state electrochromic devices

[Display omitted] •All-solid-state ECDs glass/ITO/NiO/Ta2O5/Li/WO3/ITO are prepared by e-beam and resistive evaporation method.•The all-solid-state ECDs can control the content of electrolyte ion independently.•The all-solid-state ECDs exhibit excellent electrichromic properties.•The effect of Li content on electrochromic performance is investigated. All-solid-state electrochromic devices (ECDs) with new structure glass/ITO/NiO/Ta2O5/Li/WO3/ITO, which can independently control the content of electrolyte ion by using lithium (Li) metal as the electrolyte, are fabricated by e-beam and resistive evaporation method. In this ECD, tungsten oxide (WO3) and nickel oxide (NiO) are used as the electrochromic and complementary layer, respectively, and tantalum oxide between WO3 and NiO acts as the ion conductor layer. ECDs with different thickness of Li, measured by quartz crystal deposition monitor, are prepared to investigate the effect of Li content on the electrochromic performance. The electrochemical and optical performance are characterized and the results demonstrate that the thickness of Li electrolyte has a great influence on the transmittance modulation, response time and cycle stability of the device. The ECD with 40 nm Li shows the best electrochromic performance includes the high optical modulation, superior cycle stability (optical modulation reaches 52.6% after 500 cycles) and large coloration efficiency (97.9 cm2·C−1) at wavelength of 550 nm. The ECDs displays remarkable potential for application in the field of smart windows.