Plasma-Sprayed Lithium-Ion Cathode Film Without Polymer Binders
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Solution Overview
Problem
Existing methods for fabricating cathode film layers for lithium ion batteries, such as screen printing with polymer adhesives, limit the conductivity and effective thickness of the cathode, thereby restricting the battery's electric capacity.
Innovation Solution
The method involves fabricating a cathode film layer using atmospheric plasma spraying (APS) without polymer adhesive, which allows for a high content of active substances and creates a porous structure that increases the effective reaction area with liquid electrolyte penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screen printing with polymer adhesive is used to fabricate cathode film layer, then the cathode materials can be adhered onto metal substrate, but the conductivity and effective thickness are limited, restricting battery capacity
Solution Approach 1:
The patent removes the polymer adhesive component from the cathode film structure entirely, replacing it with a metal substrate directly coated with cathode active material through plasma spraying. This extraction of the inactive adhesive layer eliminates the conductivity limitation while allowing increased effective thickness of active material for higher capacity.
Solution Approach 2:
The patent employs a porous cathode film structure created by plasma spraying, where the porous morphology provides electrolyte penetration paths and increases the effective reaction area. This porous structure allows both high conductivity through the metal substrate network and increased effective thickness of active material without compromising performance.
2Strength
If polymer adhesive is added to aggregate cathode materials, then the materials can be adhered onto substrate, but the inactive substance limits the capacitance and electric capacity
Solution Approach 1:
The patent extracts and eliminates the polymer adhesive from the system, achieving adhesion through the plasma-sprayed metal substrate coating directly bonding to the cathode active material. This removal of inactive adhesive maximizes the active substance content to approach 100 percent while maintaining structural integrity.
Solution Approach 2:
The patent creates a composite cathode structure consisting of metal substrate, plasma-sprayed cathode active material, and porous film layer without polymer adhesive. This composite approach uses functionally active materials throughout, eliminating inactive adhesive while maintaining adhesion through the metallurgical bond of the plasma-sprayed layer.
3Quantity of substance
If cathode film thickness is increased to improve capacity, then more active material is available, but the polymer adhesive limits the effective thickness and capacity increase
Solution Approach 1:
By removing the polymer adhesive layer, the patent enables the cathode film to achieve greater effective thickness with 100% active material content. The plasma-sprayed structure allows thick films to maintain both structural integrity and high active material utilization, directly increasing electric capacity without the limiting effect of inactive adhesive.
Solution Approach 2:
The patent changes the fundamental parameters of the cathode structure by eliminating the adhesive layer and using plasma spraying to create a porous thick-film structure. This parameter change allows the effective thickness to increase from typical thin-film limits to over 100 μm, directly increasing capacity while maintaining reliability through the plasma-sprayed metallurgical bond.
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 approach results in a cathode film layer with high conductivity and a thick effective thickness, significantly increasing the battery's capacity to 6 mAh/cm2, while also reducing manufacturing costs and enabling rapid production.
Implementation Method 1
plasma spraying the powder on the oxidation-resisting metal layer and exposing the powder to a plasma flame to process atmospheric plasma spraying (APS), wherein the APS uses a gas flow of argon and nitrogen uniformly mixed to obtain an atmospheric plasma flame, with a spraying power of 10-50 kilo-watts (KW), the powder is heated to a state selected from a group consisting of a molten state and a semi-molten state
Implementation Method 2
vacuum coating an oxidation-resisting metal layer onto a metal substrate
Data Source
AI summary
A method is provided for fabricating a cathode film layer of lithium ion batteries through atmospheric plasma spraying (APS) without using polymer adhesive. The ratio of active substance can approach 100%. A cathode film layer fabricated by APS is porous, where, with the coordination of a liquid electrolyte, electrolyte penetration paths are provided to significantly increase the area of reaction. Hence, the effective thickness of the film layer is relatively thick and the capacity of battery is increased. As an example, the thickness of a film layer of lithium cobalt oxide fabricated accordingly reaches more than 100 microns and its maximum electric capacity per unit area reaches 6 milliampere-hours per square centimeter (mAh/cm2).