Electrochromic Adaptability of NiOx Films Modified by Substrate Temperature in Aqueous and Non-Aqueous Electrolytes

Depending on adjusting substrate temperature during film depositing, a series of NiOx films has been prepared by magnetron sputtering. The electrochromic (EC) advantage of NiOx films modified by substrate temperature is verified. Moderate heating substrate can improve surface charge transfer (from approximate to 30 to approximate 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 NiOx films in two electrolytes is discussed. In KOH electrolyte, NiOx films at 300 degrees C substrates show prominent optical modulation (approximate to 81%) and high charge capacity (approximate to 40 mC cm(-2)). 300 degrees C heating compensates for the shortage of poor stability and tedious activation. In LiClO4-PC electrolyte, NiOx films can undergo long-term cycles compared with aqueous conditions, the coloration efficiency keeps high level (approximate to 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 NiOx films. In aqueous KOH electrolyte, EC process and activated state strongly relies on Ni2+ distribution on films surface, while NiOx experiences two phases oxidation to get thorough coloration in PC-Li based electrolyte.