Enhanced electrochromic performance on anodic nickel oxide inorganic device via lithium and aluminum co-doping

Anodic materials like nickel oxide play a very important role in lithium-ion battery, solar cells and especially electrochromic devices (ECDs). While the optical modulation and cycle stability performance of nickel oxide (NiOx) for electrochromic devices still require improvement. Here, lithium-doping (LiNiOx) and lithium-aluminum co-doping nickel oxide (Al-LiNiOx) thin films are prepared through co-sputtering. Compared with the un-doped nickel oxide films, the optical modulation and cycle stability of the nickel oxide film containing both lithium and aluminum were significantly improved. LiNiOx films show improvement in the transmittance contrast while the transmittance of bleached state decreases. Al-LiNiOx films not only increase optical modulation, but also improve the transmittance of bleached state. Furthermore, ITO/WO3/LiNbO3/Al-LiNiOx/ITO inorganic all-solid-state ECD with good performance was prepared. The transmittance of the ECD in the bleached state reaches 74.5% at 550 nm, the transmittance contrast could be 44%, and the stability of ECD is good. These indicate that lithium-aluminum co-doping could be a good way to improve electrochromic performance.