NiO Nano-Sheets Electrochromic Device Switching Speed
Solution Overview
Problem
Conventional nickel oxide (NiO)-based electrochromic energy storage devices suffer from slow switching speed due to low conductivity, resulting in insignificant coloration efficiency and sluggish performance, limiting their application in renewable energy systems.
Innovation Solution
The development of an electrochromic energy storage device with nickel oxide (NiO) nano-sheets having a porous structure and interconnected nanoflakes, grown on a fluorine-doped tin oxide glass substrate using a hydrothermal process, which enhances the switching speed and performance by improving the interface and reducing charge transfer resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional NiO-based EC-ESDs are used, then the device structure is simple, but the switching speed is slow due to low conductivity
Solution Approach 1:
The patent employs porous NiO nano-sheets with a hierarchical porous structure consisting of nanoflakes (5-29 nm width) forming interconnected sheets. This porous architecture increases the surface area and provides multiple pathways for ion transport, significantly enhancing the switching speed from seconds to sub-second range while maintaining the fundamental NiO-based device structure
Solution Approach 2:
The patent transitions from conventional bulk or dense film NiO structures to a nano-sheets architecture with controlled thickness (100-2,000 nm). This dimensional reduction creates a hierarchical structure with nanoflakes forming sheets, adding structural complexity at the nanoscale while improving bulk conductivity through enhanced ion transport pathways
2Use of energy by moving object
If conventional NiO-based EC-ESDs are used, then the fabrication process is simple, but the coloration efficiency is insignificant
Solution Approach 1:
The porous nano-sheets structure with high surface area (300-350 m2/g) and controlled pore size (70-90 nm) provides extensive active sites for electrochromic reactions. This increases the amount of active NiO material accessible to electrolyte ions, thereby significantly improving coloration efficiency while maintaining hydrothermal fabrication simplicity
Solution Approach 2:
The patent optimizes multiple parameters including nanoflake width (5-29 nm), sheet thickness (100-2,000 nm), and pore size (70-90 nm) to maximize coloration efficiency. These parameter adjustments are achieved through controlled hydrothermal processing conditions, improving performance without fundamentally changing the fabrication approach
3Loss of time
If conventional NiO-based EC-ESDs are used, then the device structure is simple, but the switching response time is sluggish
Solution Approach 1:
The patent divides the NiO structure into segmented nanoflakes (5-29 nm width) that form interconnected sheets. This segmentation creates numerous small pathways for ion intercalation and de-intercalation, reducing the diffusion distance and enabling faster switching response times compared to conventional bulk NiO structures
Solution Approach 2:
The hierarchical porous structure with interconnected nanoflakes and sheets provides multiple rapid transport pathways for ions. The porosity enables electrolyte penetration throughout the NiO structure, significantly reducing ion transport time and achieving switching response times of 0.5-1 second for coloration and 0.1-0.5 second for bleaching
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves a high areal capacitance, excellent capacity retention after 1,000 charge-discharge cycles, and fast switching response times for coloration and bleaching, with improved optical modulation and coloration efficiency, making it suitable for high-performance electrochromic energy storage applications.
Implementation Method 1
the slow intercalation/de-intercalation process
Implementation Method 2
Some of the electrode materials alter their colors during the charging and discharging process, which is known as electrochromism
Data Source
AI summary
An electrochromic energy storage device is described. An electrochromic energy storage device includes a first substrate, a second substrate, an electrolyte present between the first substrate and the second substrate. The device further includes nickel oxide (NiO) nano-sheets that at least partially cover a first side of the first substrate. Further, the NiO nano-sheets are comprised of interconnected nanoflakes, where the nanoflakes have a width of 5-29 nanometers (nm). A method of preparing the NiO nano-sheets is also described.