Lithium Battery Positive Electrode Slurry with Tungsten Trioxide
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Solution Overview
Problem
The high pH of aqueous positive active material slurry in lithium batteries leads to corrosion of aluminum electrode substrates, resulting in the formation of pinholes and increased internal resistance due to the reaction of aluminate ions with water, which compromises the performance and lifespan of the battery.
Innovation Solution
Incorporating tungsten trioxide (WO3) into the positive electrode material, which acts as a strong oxidizer and suppresses the corrosion reaction, forming an alumina film and preventing hydrogen gas production, while providing low electrical resistivity and good conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aqueous binder is used in positive electrode slurry, then ease of manufacture is improved, but aluminum electrode substrate corrodes due to high pH
Solution Approach 1:
A coating layer comprising tungsten trioxide (WO3) and/or molybdenum trioxide (MoO3) is applied as an intermediary between the aqueous binder and the aluminum electrode substrate. This coating layer acts as a protective barrier that prevents direct contact between the alkaline slurry and the aluminum substrate, thereby preventing corrosion while allowing the aqueous binder to perform its binding function.
Solution Approach 2:
The invention changes the chemical composition parameters of the electrode structure by introducing metal oxide coating layers with specific properties. The coating layer has different pH resistance characteristics compared to the bulk slurry, creating a gradient that protects the aluminum substrate from high pH damage while maintaining the benefits of aqueous binding.
2Reliability
If aluminum electrode substrate is used, then electrical conductivity is improved, but pin holes are formed due to corrosion reaction
Solution Approach 1:
The metal oxide coating layer serves as a protective intermediary that prevents the corrosion reaction between aqueous binder and aluminum substrate. By blocking the interaction between aluminate ions and water, the coating prevents hydrogen gas generation and pin hole formation, thereby maintaining electrode surface integrity while preserving the electrical conductivity of the aluminum substrate.
Solution Approach 2:
The coating layer is applied in advance before the electrode assembly is completed, creating a preliminary protective barrier against corrosion. This pre-protection prevents the harmful reaction from occurring in the first place, rather than attempting to repair damage after it occurs.
3Object-affected harmful factors
If coating layer with metal oxide is applied, then aluminum corrosion is prevented, but device complexity increases
Solution Approach 1:
The invention creates a composite electrode structure by combining the aluminum substrate with a metal oxide coating layer. This composite structure integrates the high electrical conductivity of aluminum with the corrosion resistance of metal oxides, achieving protection without requiring complex multi-component systems or elaborate protective mechanisms.
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 use of tungsten trioxide effectively prevents aluminum corrosion, reduces electrode resistance, and enhances the battery's rate characteristics and lifespan by maintaining the integrity of the electrode surface and improving electrical conductivity.
Implementation Method 1
Incorporating tungsten trioxide (WO3) into the positive electrode material, which acts as a strong oxidizer and suppresses the corrosion reaction, forming an alumina film and preventing hydrogen gas production
Implementation Method 2
providing low electrical resistivity and good conductivity
Data Source
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AI summary
A positive electrode material for a lithium battery, a positive electrode prepared from the positive electrode material, and a lithium battery including the positive electrode are disclosed. The positive electrode material includes a positive active material, an aqueous binder, and tungsten trioxide. Due to the inclusion of the positive active material, the aqueous binder, and the tungsten trioxide (WO3), the positive electrode material may substantially prevent corrosion of an aluminum substrate. The positive electrode material has high electric conductivity. Lithium batteries including positive electrodes prepared from the positive electrode material have decreased resistance of the electrode plate, high rate characteristics, and good lifespan characteristics.