Multilayered Electrode for Energy Storage Devices
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Solution Overview
Problem
Existing super-capacitor electrodes tend to inject electrons into the dielectric layer, leading to increased leakage currents and limiting the maximum working voltage, which restricts the energy storage capacity of energy storage devices.
Innovation Solution
A multilayered electrode structure comprising an electro-conductive layer and at least one protective layer, including a field-planarization layer, a tunneling injection blocking layer, or a coulomb blocking layer, is introduced to minimize electric field enhancement and prevent electron injection, thereby reducing leakage currents. The protective layers can be arranged in various sequences, such as electro-conductive layer followed by a field-planarization layer, a tunneling injection blocking layer, and a coulomb blocking layer, or other combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple electro-conductive layer is used as electrode, then device complexity is reduced, but electron injection into dielectric layer increases leading to higher leakage currents
Solution Approach 1:
The electrode is segmented into multiple functional layers: an electro-conductive layer for charge conduction and one or more protective layers (field-planarization layer, tunneling injection blocking layer, and/or coulomb blocking layer) for preventing electron injection. This segmentation allows each layer to perform its specific function optimally, reducing overall leakage current while maintaining electrical conductivity.
Solution Approach 2:
Protective layers are introduced as intermediary layers between the electro-conductive layer and the dielectric layer. These intermediary layers act as barriers that prevent direct electron injection from the electro-conductive layer into the dielectric layer, thereby reducing leakage currents without compromising the electrical function of the electrode.
2Quantity of substance
If working voltage is increased to enhance energy storage capacity, then energy density improves, but electron injection and leakage currents increase
Solution Approach 1:
Protective layers are applied in advance to the electro-conductive layer to prevent electron injection before it can occur during high-voltage operation. The field-planarization layer smooths electric field distribution, the tunneling injection blocking layer prevents quantum tunneling, and the coulomb blocking layer repels electrons via electrostatic repulsion, collectively preventing electron injection even when high working voltages are applied.
Solution Approach 2:
The electrode uses a composite structure combining different materials with complementary properties: highly conductive materials for the electro-conductive layer and materials with high electron affinity, wide bandgap, or electron trap capabilities for the protective layers. This composite approach enables the electrode to withstand high working voltages while maintaining low leakage currents.
3Object-generated harmful factors
If protective layers are added to prevent electron injection, then leakage current decreases, but device complexity and manufacturing steps increase
Solution Approach 1:
Protective layers are applied selectively to the electro-conductive layer where electron injection occurs. The field-planarization layer is applied to regions with high electric field concentration, and protective layers are positioned at the electrode-dielectric interface where electron injection is most likely to occur, optimizing protection while minimizing unnecessary complexity.
Solution Approach 2:
The properties of protective layers (thickness, material composition, electron affinity, bandgap energy) are optimized to achieve effective electron injection prevention with minimal impact on device performance. By carefully controlling these parameters, the protective layers provide maximum protection against leakage currents while maintaining reasonable device complexity.
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 multilayered electrode structure effectively decreases leakage currents and enhances the energy storage capacity by preventing electron injection into the dielectric layer, allowing for increased working voltage and improved energy density in energy storage devices.
Implementation Method 1
minimize electric field enhancement due to geometric curvature on the surface of the electro-conductive layer
Implementation Method 2
A tunneling injection blocking layer comprises a wide-band gap organic insulating material
Implementation Method 3
A coulomb blocking layer comprises electron traps
Data Source
AI summary
The present disclosure provides a multilayered electrode comprising an electro-conductive layer and at least one protective layer located on one side of the electro-conductive layer and selected from the list comprising a field-planarization layer, a tunneling injection blocking layer and a coulomb blocking layer.