Reliable, High-Performance Electrochromic Supercapacitors Based on Metal-Doped Nickel Oxide

Abstract

Herein, high-performance, reliable electrochromic supercapacitors (ECSs) are proposed based on tungsten trioxide (WO3) and nickel oxide (NiO) films. To maximize device performance and stability, the stoichiometric balance between anode and cathode materials is controlled by carefully adjusting the thickness of the anodic NiO film while fixing the thickness of WO3 to ∼660 nm. Then, a small amount (≤10 mol %) of metal (e.g., copper) is doped into the NiO film, improving the electrical conductivity and electrochemical activity. At a Cu doping level of 7 mol %, the resulting ECS exhibited the highest performance, including a high areal capacitance (∼14.9 mF/cm2), excellent coulombic efficiency (∼99%), wide operating temperature range (0–80 °C), reliable operation with high charging/discharging cyclic stability (>10,000 cycles), and good self-discharging durability. Simultaneously, the change in transmittance of the device is well synchronized with the galvanostatic charging/discharging curve by which the real-time energy storage status is visually indicated. Furthermore, the practical feasibility of the device is successfully demonstrated. These results imply that the ECS fabricated in this work is a promising potential energy storage platform and an attractive component for future electronics.

Advanced developments in nonstoichiometric tungsten oxides for electrochromic applications

“…As a result, the stored energy could be utilized to derive other functional devices. Tremendous progress has been made in smart electronics and dual/multifunctional windows for practical applications in which the WO 3 & NiO 436 -based EC supercapacitor have been widely demonstrated. 437 The dual-function EC supercapacitors served as either an energy storage device or electrical power source simultaneously, displaying its real-time capacity in the color state.…”

“…437 A small amount of doping less than 10 mol % significantly enhanced the EC performance. 436 Moreover, smart windows with unique novel multifunctional features extend their utility. Metal oxides become opaque upon ion extractions such as oxides of nickel, and iridium or PEDOT/PSS materials.…”

Electrochromic Properties of the Vanadium Pentoxide Doped with Nickel as an Ionic Storage Layer

“…The process of metal-doping of the electrochromic oxide shows high-performance and reliability has been proposed on tungsten trioxide (WO 3 ) and nickel oxide (NiO) film [11,12]. The chromic mixed metal oxide films often show more natural colors than intrinsic ones in their coloring states.…”

Recent progress on novel current collector electrodes for energy storage devices: Supercapacitors

“…Charging/discharging cycle and performance of tungsten and nickel oxides‐based electrochromic supercapacitor device used to power a mini fan and simultaneously exhibit a color change (adapted from S. Y. Kim, Yun, et al, 2020)…”