Secondary Battery Electrode With Graphene-CNT Conductive Network
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in maintaining low electrode resistance and improving battery life characteristics due to the degradation of conductive networks during charge and discharge cycles.
Innovation Solution
The use of an electrode active material layer that includes a conductive agent comprising a secondary particle with interconnected graphene sheets and a carbon nanotube structure, where the carbon nanotube structure is formed by bonding 2 to 5,000 single-walled carbon nanotube units, and is included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-walled carbon nanotube units are completely dispersed to improve conductivity, then electrical conductivity is improved, but the carbon nanotube structure is damaged or broken during charge and discharge cycles, degrading battery life characteristics
Solution Approach 1:
The patent combines multiple single-walled carbon nanotube units (2 to 5,000 units) to form bundled carbon nanotube structures. This merging approach maintains the high electrical conductivity of individual nanotubes while creating a more robust, damage-resistant network that persists through repeated charge and discharge cycles, thereby improving both conductivity and battery longevity.
Solution Approach 2:
The patent creates a composite conductive network by bundling multiple carbon nanotube units together. This composite structure combines the advantages of individual nanotubes (high conductivity) with enhanced mechanical strength and stability, resulting in a conductive agent that maintains performance over extended battery operation periods.
2Duration of action of stationary object
If multi-walled carbon nanotubes are used to ensure conductivity during surface damage, then battery life is improved, but the nanotubes are cut to excessively short lengths during dispersion preparation, limiting conductivity improvement
Solution Approach 1:
The patent segments the multi-walled carbon nanotube structure into multiple individual single-walled carbon nanotube units while maintaining their bundled arrangement. This segmentation during the dispersion process prevents excessive cutting and shortening, allowing the nanotubes to retain sufficient length for effective conductivity enhancement while still providing the durability benefits of bundled structures.
3Reliability
If graphene is used as a plane-type conductive agent, then electrical conductivity is excellent, but electrolyte solution mobility is limited due to wide planar contact
Solution Approach 1:
The patent adopts the curved, tubular structure of carbon nanotubes instead of the flat planar structure of graphene. This curved geometry provides excellent electrical conductivity along the nanotube walls while maintaining open spaces between nanotubes in the bundled structure, allowing electrolyte solution to flow freely and access active material particles efficiently, thus resolving the mobility limitation of planar graphene.
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
This configuration maintains a stable conductive network even during repeated charge and discharge cycles, reducing electrode resistance and enhancing battery life characteristics by preventing damage to the carbon nanotube structure and promoting uniform electrolyte solution mobility.
Implementation Method 1
the conductive agent includes a first conductive agent and a second conductive agent, wherein the first conductive agent includes a secondary particle in which a plurality of graphene sheets are arranged in different directions and a portion of one graphene sheet is connected to a portion of adjacent another graphene sheet, the second conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other
Implementation Method 2
a plurality of graphene sheets are arranged in different directions and a portion of one graphene sheet is connected to a portion of adjacent another graphene sheet
Data Source
AI summary
An electrode includes an electrode active material layer, wherein the electrode active material layer includes an electrode active material and a conductive agent, wherein the conductive agent includes a first conductive agent and a second conductive agent, wherein the first conductive agent includes a secondary particle in which a plurality of graphene sheets are arranged in different directions and a portion of one graphene sheet is connected to a portion of adjacent another graphene sheet, the second conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure is included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer. A secondary battery including the electrode is also provided.