Lithium Air Battery Positive Electrode Dry Process
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Solution Overview
Problem
Conventional wet processes for manufacturing lithium air battery electrodes are complex and prone to uneven material distribution due to solvent-related issues, leading to reduced durability and energy density, and require a current collector which increases battery weight.
Innovation Solution
A dry process using ball-milling of a mixture of active materials and binders to enhance coupling force, eliminating the need for a positive electrode current collector and allowing for a high-density, porous electrode structure with polytetrafluoroethylene (PTFE) as the binder, which is applied to release paper and rolled to form the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a foam- or mesh-type current collector is used to allow oxygen flow, then oxygen permeability is improved, but material distribution uniformity deteriorates
Solution Approach 1:
The invention extracts and eliminates the current collector component entirely from the lithium air battery electrode structure. By removing the foam- or mesh-type current collector that caused non-uniform material distribution, the patent achieves both excellent oxygen permeability and uniform material distribution through the slurry coating method described in claims 1-10.
Solution Approach 2:
Instead of using a current collector to support the electrode structure, the invention inverts the approach by using a flexible substrate without a current collector, allowing the electrode materials themselves to form the structural framework. This inversion resolves the contradiction by eliminating the source of non-uniform distribution while maintaining structural integrity.
2Reliability
If the binder content is increased to improve material fixation on foam/mesh current collector, then electrode structural stability is improved, but electrode density deteriorates
Solution Approach 1:
The invention removes the foam- or mesh-type current collector that necessitated high binder content for material fixation. Without this porous current collector structure, the electrode achieves structural stability through alternative means (slurry formulation and coating process described in claims 1-10) while maintaining high density by using minimal binder content.
Solution Approach 2:
The invention changes the fundamental parameter of current collector presence from 'present' to 'absent', which fundamentally alters the binder content requirement. This parameter change enables the electrode to achieve both structural stability and high density by optimizing binder content at low levels (1-30 wt%) as specified in claim 1.
3Strength
If a positive electrode current collector is used to support the electrode, then electrode structural integrity is improved, but battery weight increases
Solution Approach 1:
The invention extracts and removes the positive electrode current collector from the battery structure entirely. By eliminating this component, the patent achieves both electrode structural integrity through alternative mechanisms (flexible substrate and optimized slurry composition in claims 1-10) and significant weight reduction, directly addressing the contradiction between structural integrity and weight.
Solution Approach 2:
The invention replaces the traditional durable current collector with a flexible substrate approach that uses minimal material. This substitution achieves the necessary structural integrity for electrode functionality while dramatically reducing weight, effectively using a 'less is more' strategy that aligns with the disposable principle of eliminating unnecessary permanent structures.
4Ease of manufacture
If a slurry coating method is used on foam/mesh current collector, then electrode manufacturing is simplified, but material distribution uniformity deteriorates
Solution Approach 1:
The invention removes the foam- or mesh-type current collector that caused non-uniform material distribution during slurry coating. By eliminating this problematic substrate, the patent maintains the simplicity of the slurry coating method while achieving uniform material distribution, as the slurry can now be applied directly to a flexible substrate without the interference of porous current collector structures.
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 method increases the durability and energy density of lithium air batteries by reducing weight and extending lifespan, while avoiding solvent-related swelling and enabling a flexible, high-density electrode without a positive electrode current collector.
Implementation Method 1
ball-milling a mixture of 70 to 99 wt % of a positive electrode active material and 1 to 30 wt % of a binder to manufacture an electrode mixture
Implementation Method 2
applying the electrode mixture to release paper and rolling the electrode mixture to manufacture an electrode
Data Source
AI summary
The present disclosure relates to a positive electrode for lithium air batteries, a method of manufacturing the positive electrode, and a lithium air battery including the positive electrode, and more particularly to a positive electrode for lithium air batteries, wherein the positive electrode is manufactured through a dry process instead of a conventional wet process and a mixture of a positive electrode active material and a binder is ball-milled under specific conditions, thereby reducing or preventing a swelling phenomenon due to a solvent and increasing the force of coupling between the positive electrode active material and the binder, whereby it is possible to manufacture a high-density electrode and to improve the durability of the electrode, and wherein the lifespan of a lithium air battery is increased when the positive electrode is applied to the battery.