Electrochromic Adaptability of NiO<i><sub>x</sub></i> Films Modified by Substrate Temperature in Aqueous and Non‐Aqueous Electrolytes
Yilin Ding, Mengying Wang, Mengying Wang, Zheyue Mei, Lei Liu, Jiaming Yang, Xiaolan Zhong, Mei Wang, Mei Wang, Xungang Diao
Abstract
Abstract Depending on adjusting substrate temperature during film depositing, a series of NiO x films has been prepared by magnetron sputtering. The electrochromic (EC) advantage of NiO x films modified by substrate temperature is verified. Moderate heating substrate can improve surface charge transfer (from ≈30 to ≈40 mC cm −2 ) and energy storage capacity (45% increment) without damaging other performance effectively. Considering the different electrochemical mechanisms in varied electrolytes, the EC performance of NiO x films in two electrolytes is discussed. In KOH electrolyte, NiO x films at 300 °C substrates show prominent optical modulation (≈81%) and high charge capacity (≈40 mC cm −2 ). 300 °C heating compensates for the shortage of poor stability and tedious activation. In LiClO 4 ‐PC electrolyte, NiO x films can undergo long‐term cycles compared with aqueous conditions, the coloration efficiency keeps high level (≈80 cm 2 C −2 ) which means small charge quantities can drive a wide transmittance range. The cyclic discrepancy in two electrolytes can be ascribed to diverse reacted modes between electrolyte ions and NiO x films. In aqueous KOH electrolyte, EC process and activated state strongly relies on Ni 2+ distribution on films surface, while NiO x experiences two phases oxidation to get thorough coloration in PC‐Li based electrolyte.