Composite CNT Electrode Structure With Low CNT Content
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Solution Overview
Problem
Carbon nanotubes (CNTs) are expensive and pose challenges during electrode manufacturing, necessitating an electrode material that exhibits their advantageous properties while minimizing CNT content.
Innovation Solution
A composite electrode structure with a network of carbon nanotubes binding carbonaceous material, such as activated carbon, where the carbon nanotubes make up less than 10% by weight, and an adhesion layer of carbon nanotubes between the active layer and a conductive layer, facilitating energy storage with high performance capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbon nanotubes are used as the primary electrode material, then high energy density and power density are achieved, but manufacturing cost increases and manufacturing complexity increases
Solution Approach 1:
The patent creates a composite electrode structure combining carbon nanotubes (5-20 weight%) with carbonaceous material (80-95 weight%). This composite approach allows the electrode to achieve high power density through the conductive CNT network while reducing manufacturing cost by using abundant, inexpensive carbonaceous material as the primary active component.
Solution Approach 2:
The patent optimizes the weight percentage of carbon nanotubes to a specific range (5-20%, preferably 10-15%) rather than using pure CNTs. This parameter optimization maintains the essential electrical conductivity and structural benefits of CNTs while significantly reducing the amount of expensive CNT material required, thereby lowering manufacturing costs.
2Reliability
If pure carbon nanotube networks are used, then excellent electrical conductivity is achieved, but material cost increases
Solution Approach 1:
The patent introduces carbonaceous material as an intermediary substance that works in conjunction with carbon nanotubes. The carbonaceous material fills the spaces between CNTs and provides additional conductive pathways, allowing the system to achieve excellent electrical conductivity with reduced CNT content. The CNTs act as a conductive scaffold while the carbonaceous material supplements the conductivity.
Solution Approach 2:
By creating a composite where carbonaceous material (80-95 weight%) serves as the bulk material and carbon nanotubes (5-20 weight%) provide the conductive network, the patent achieves excellent electrical conductivity without requiring high CNT content. The synergistic interaction between the two materials allows cost reduction while maintaining performance.
3Strength
If binder materials are added to hold electrode particles together, then mechanical strength is improved, but electrical conductivity decreases and energy density is reduced
Solution Approach 1:
The patent removes binder materials from the electrode composition entirely. Instead of using polymer binders that would reduce conductivity and energy density, the electrode relies on the inherent mechanical strength of the carbon nanotube network and the adhesion between carbonaceous material particles and the current collector to maintain structural integrity.
Solution Approach 2:
The carbon nanotube network and carbonaceous material structure serve their own mechanical support function without requiring external binders. The CNTs form a robust three-dimensional scaffold that provides mechanical strength, while the carbonaceous material particles interlock within this scaffold, creating a self-supporting structure that eliminates the need for separate binder materials.
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 composite electrode achieves high operating voltage, high energy and power density, low equivalent series resistance, and durability at elevated temperatures, extending the lifespan of ultracapacitors to at least 1,000 hours.
Implementation Method 1
the active layer is bound together by electrostatic forces between the carbon nanotubes and the carbonaceous material
Implementation Method 2
an adhesion layer, e.g., a layer consisting of or consisting essentially of carbon nanotubes... disposed between the active laver and an electrically conductive layer
Data Source
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AI summary
An apparatus is disclosed that includes an active storage layer including: a network of carbon nanotubes defining void spaces; and a carbonaceous material located in the void spaces and bound by the network of carbon nanotubes. In some cases, the active layer provides energy storage, e.g., in an ultracapacitor device.