Development of Laminated Nickel/Manganese Oxide and Nickel/Niobium Oxide Electrochromic Devices

We report on the prepation, electrical and optical analysis of eIectrodes and prototype electrochromic devices using a solid polymer ion conductor. For these devices we developed electrodes consisting of cobalt-doped nickel oxide, manganese-nickel oxide, and niabium oxide. Optical and voltammetric data was obtained for each electrode. Solid polymer electrolytes were synthesized from modified amorphous poly(ethy1ene oxide) [a-PEO] complexed with a metal silicate. Electrochromic devices were made using cobalt-doped nickel oxide/niobium oxide, and cobalt-doped nickel oxide/manganese-nickel electrode laminations. Optical spectra as a function of voltage was obtained for each device. Our best cobalt-doped nickel oxide/a-PEO/rnanganese-nickel oxide device showed photopic transmittance to be T_p(bleached)=0.76 and T_p(colored)=0.44. The corresponding integrated solar transmittance was T_s(bleached)=0.64, T_s(colored)=0.46. Our best cobalt-doped nickel oxide/a-PEO/niobium oxide device had photopic transmittance of T_p(bleached)=0.65 and T_p(colored)=0.16. The corresponding integrated solar transmittance was T_s(bleached)=0.45 and T_s(colored)=0.15. Of the two devices, the nickel/niobium oxide device had the best combination of electrical and optical properties. Better device properties are expected with improvements in the solid polymer electrolyte and lamination process.