CNT Electrode Structure With Carbide Interface for Low-ESR Ultracapacitors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The effective transfer and integration of carbon nanotubes (CNTs) onto a current collector for capacitors have proven challenging, leading to suboptimal performance in terms of power density, energy density, equivalent series resistance (ESR), frequency response, and stability due to the use of bonding layers that increase ESR and decrease energy and power density.
Innovation Solution
The use of an aluminum current collector with an aluminum carbide layer, onto which vertically-aligned, horizontally-aligned, or non-aligned CNTs are disposed, either by direct growth or transfer methods, allowing for the creation of high-performance electrodes with optional additional layers, and the incorporation of these electrodes into ultracapacitors with specific electrolytes and separators for enhanced electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bonding layer is used to cause CNTs to adhere to the current collector, then adhesion is improved, but ESR increases and energy density and power density decrease
Solution Approach 1:
The patent removes the bonding layer from the electrode structure entirely. CNTs are transferred directly to the current collector surface without any intermediate bonding layer, eliminating the source of increased ESR and energy loss while maintaining adhesion through direct contact between CNTs and the current collector
Solution Approach 2:
The patent creates an asymmetric interface where CNTs make direct contact with the current collector surface, eliminating the symmetric layered structure (current collector-bonding layer-CNTs) that introduced additional resistance. This direct interface reduces the number of contact points and minimizes ESR
2Reliability
If a bonding layer is used to cause CNTs to adhere to the current collector, then adhesion is improved, but energy density and power density decrease
Solution Approach 1:
The bonding layer is completely removed from the structure. CNTs are transferred directly to the current collector, eliminating the intermediate layer that impeded electron transport and reduced power density. The direct contact enables more efficient charge transfer
Solution Approach 2:
The patent changes the interface parameters by eliminating the bonding layer, thereby reducing interfacial resistance and improving electron transport efficiency. This parameter change directly enhances power density by enabling faster charge transfer between CNTs and the current collector
3Ease of manufacture
If CNTs are transferred onto a current collector, then electrode formation is achieved, but transfer efficiency and performance optimization are challenging
Solution Approach 1:
The patent applies preliminary action by pre-treating the current collector surface with plasma or chemical methods before CNT transfer. This preparation creates an optimized surface that enhances CNT adhesion and uniformity, making the subsequent transfer process more efficient and achieving better performance without complex post-processing
Solution Approach 2:
The patent optimizes transfer parameters such as temperature, pressure, and atmosphere during the CNT transfer process. By controlling these parameters, the method achieves high transfer efficiency while maintaining precise control over CNT distribution and orientation, thereby optimizing performance
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 resulting energy storage devices exhibit improved gravimetric and volumetric power and energy densities, reduced ESR, and enhanced frequency response, achieving higher performance than previous technologies while maintaining cost-effectiveness and simplicity in production.
Implementation Method 1
an aluminum current collector with an aluminum carbide layer, onto which vertically-aligned, horizontally-aligned, or non-aligned CNTs are disposed
Data Source
AI summary
Disclosed herein is electrode comprising a current collector comprising a conductor layer having at least a first surface; and elongated metal carbide nanostructures extending from the first surface; and a carbonaceous energy storage media disposed on the first surface and in contact with the elongated metal carbide nanostructures. Disclosed herein too is an ultracapacitor comprising at least one electrode comprising a current collector comprising a conductor layer having at least a first surface; and elongated metal carbide nanostructures extending from the first surface; and a carbonaceous energy storage media disposed on the first surface and in contact with the elongated metal carbide nanostructures.