Graphene Current Collectors for Lithium Ion Batteries
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Solution Overview
Problem
Lithium ion batteries face challenges with low power density and short lifespan due to the weight and corrosion of traditional metal foils used as current collectors.
Innovation Solution
The use of graphene layers as current collectors, which are lightweight, conductive, and chemically stable, replacing traditional metal foils, and incorporating carbon nanotubes to form integral net structures for the cathode and anode material layers without adhesives, enhancing conductivity and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If metal foils are used as current collectors, then conductivity is ensured, but weight increases and power density decreases
Solution Approach 1:
The patent changes the material parameter of the current collector from traditional metal foils to carbon-based materials (graphene, carbon nanotubes). This material substitution fundamentally alters the weight-to-conductivity ratio, achieving lower weight while maintaining or improving electrical conductivity, thereby increasing power density.
Solution Approach 2:
The patent employs composite carbon structures combining graphene layers and carbon nanotubes. The graphene provides excellent electrical conductivity and flexibility, while carbon nanotubes contribute high strength-to-weight ratio and structural integrity. This composite approach achieves superior performance compared to single-material solutions.
2Reliability
If metal foils are used as current collectors, then electrical connection is achieved, but corrosion occurs and lifespan decreases
Solution Approach 1:
The patent changes the chemical composition parameter of the current collector from metal-based to carbon-based materials. Carbon materials exhibit superior chemical stability and immunity to electrolyte corrosion compared to metals, eliminating the corrosion problem while maintaining electrical conductivity and extending battery lifespan.
Solution Approach 2:
The patent replaces expensive, corrosion-prone metal foils with more stable carbon-based materials that do not degrade in the electrolyte environment. This substitution eliminates the need for protective coatings and reduces maintenance requirements, improving long-term reliability.
3Strength
If adhesive is used to bind electrode materials, then structural integrity is achieved, but conductivity decreases and complexity increases
Solution Approach 1:
The patent removes the adhesive layer from the electrode structure entirely. Instead of using adhesive to bind active materials to the current collector, the carbon nanotube network itself serves as both the structural framework and the conductive pathway, eliminating the insulating adhesive layer that would otherwise reduce conductivity.
Solution Approach 2:
The carbon nanotube network performs multiple functions simultaneously: it provides structural support for the electrode, ensures electrical conductivity, and acts as the current collector itself. This multi-functional design eliminates the need for separate adhesive and current collector layers, simplifying the structure while improving 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
This configuration results in lithium ion batteries with higher power density and extended lifespan by reducing weight and corrosion, while maintaining stability and conductivity.
Implementation Method 1
The current collector is used to collect the charge generated by the lithium ion battery during discharge, and to connect to an external power source during the recharging of the lithium ion battery. The current collectors are usually made of metal foils, such as copper foil and aluminum foil.
Implementation Method 2
incorporating carbon nanotubes to form integral net structures for the cathode and anode material layers without adhesives, enhancing conductivity and structural integrity
Implementation Method 3
The anode, cathode, and separator are infiltrated by the non-aqueous electrolyte. The separator is located between the anode and the cathode.
Data Source
AI summary
A lithium ion battery includes at least one battery cell. The battery cell includes a cathode electrode, an anode electrode, and a separator. The separator is sandwiched between the cathode electrode and the anode electrode. At least one of the cathode electrode and the anode electrode includes a current collector. The current collector is a graphene layer.