Graphene Oxide Nanocoating Separator for Li-Ion Batteries
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Solution Overview
Problem
Current Li-ion batteries face limitations in achieving high energy density due to sluggish Li-ion transport through dense coatings, leading to low Coulombic efficiency and complex, costly methods for improving lithium metal battery performance.
Innovation Solution
A battery structure incorporating a porous separator with a thin, three-dimensional graphene oxide (GO) nanosheet coating that regulates Li-ion transport and suppresses lithium dendrite deposition, utilizing a woven glass-fiber separator with GO nanosheets to facilitate uniform lithium deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense layer-by-layer coating is formed on the separator surface to suppress lithium dendrites, then dendritic deposition is suppressed, but Li-ion transport becomes sluggish and Coulombic efficiency decreases
Solution Approach 1:
The patent employs a porous coating layer with controlled porosity (30-70%) formed by incorporating porous nanomaterials such as carbon nanotubes, graphene, or metal organic frameworks. This porous structure allows Li-ion transport channels to remain open while the coating provides mechanical suppression of dendrite growth, resolving the contradiction between dendrite suppression and ion transport efficiency
Solution Approach 2:
The patent uses composite coating materials combining organic polymers with inorganic nanomaterials (e.g., PVDF-HFP with SiO2 nanoparticles, or polyacrylonitrile with carbon nanotubes). This composite approach provides both the mechanical strength needed for dendrite suppression and the porous pathways necessary for efficient Li-ion transport, achieving both goals simultaneously
2Productivity
If nitrogen/sulfur doping or CNT spacers are added to open channels for Li-ion transport, then ion transport improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs cost-effective nanomaterials such as oxidized carbon nanotubes, graphene oxide, or simple metal oxides that can be incorporated through straightforward coating processes. These materials provide the necessary porous structure without requiring complex doping procedures or expensive precursors, reducing both material cost and manufacturing complexity while maintaining high Li-ion transport rates
3Weight of moving object
If an ultra-thin coating is applied to the separator to reduce weight, then battery weight decreases, but mechanical stability and ion transport regulation capability may be compromised
Solution Approach 1:
The patent applies coating materials with locally optimized properties where the coating thickness and porosity are tailored to specific regions of the separator. The coating is designed to be ultra-thin (nanometer scale) in areas requiring flexibility and weight reduction, while maintaining sufficient mechanical integrity through strategic placement of reinforcing nanomaterials at critical stress points, achieving both weight reduction and mechanical stability
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 GO nanosheet coating enhances cycle life and stability of Li-metal anodes, achieving improved Coulombic efficiency and preventing dendritic lithium growth, while maintaining mechanical stability and reducing weight, thus promoting dense and uniform lithium deposition.
Implementation Method 1
The GO nanosheet coating is configured as a buffer layer to permit transport of Li-ions therethrough and to regulate a rate of flow of the transport of the Li-ions
Implementation Method 2
The separator can be porous and configured to embed or integrate the thin coating at least partially within the structure thereof
Implementation Method 3
The 3D mechanically stable coating is formed such that dendritic deposition on the battery electrode surface is advantageously suppressed
Data Source
AI summary
The disclosure provides a battery and methods for making and using the battery. The battery includes (a) a separator that is woven and porous, and (b) a graphene oxide (GO) nanosheet coating coupled to a surface of the separator. The GO nanosheet coating is configured as a buffer layer to permit transport of Li-ions therethrough and to regulate a rate of flow of the transport of the Li-ions.