Electro-optical performance of inorganic monolithic electrochromic device with a pulsed DC sputtered Li_xMg_yN ion conductor

Lithium magnesium nitride (Li_xMg_yN) thin films were deposited by pulsed DC reactive magnetron sputtering from a LiMg alloy target in the mixture gas of Ar and N₂. The as-prepared Li_xMg_yN films were amorphous. A monolithic inorganic electrochromic device (ECD) based on WO₃/NiO complementary structure was fabricated using the Li_xMg_yN as the ion conductor layer. The addition of a 150-nm thick Si₃N₄ buffer layer between Li_xMg_yN and NiO made coloration and bleaching reversible and stable. Electrochemical and optical characterizations were conducted to evaluate the performance of the ECD. Electro-optical data were recorded for both 1000 chronoamperometric cycles and 1000 voltammetric cycles. Activation and degradation of the electro-optical properties of the ECD were observed.