Transition Metal Oxide Cathode Composition for Lithium Battery Corrosion Prevention
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Solution Overview
Problem
Lithium secondary batteries face increased internal resistance due to corrosion of aluminum electrode base materials caused by high pH levels from unreacted alkali metal ions, leading to reduced high-rate characteristics and lifespan.
Innovation Solution
Incorporating a transition metal oxide, such as manganese-based oxides (MnO, MnO2, Mn2O3, Mn3O4, Mn2O7), into the cathode active material composition to prevent corrosion by oxidizing aluminum and forming a protective Al2O3 layer, thereby maintaining a stable pH and reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a water-based binder is used to prepare the electrode plate, then the electrode becomes strongly basic due to unreacted alkali metal ions, but this causes corrosion of the aluminum electrode base material
Solution Approach 1:
A pH buffer is introduced as an intermediary substance to mediate between the water-based binder and the aluminum electrode base material. The buffer controls the pH level, preventing it from becoming too high, thus avoiding corrosion of the aluminum base material while still allowing the use of water-based binders for ease of manufacture.
Solution Approach 2:
The pH level parameter of the water-based binder is actively controlled and adjusted using a pH buffer. By maintaining the pH within a specific range (preventing it from becoming strongly basic), the invention changes the chemical environment to prevent corrosion while preserving the manufacturing advantages of water-based binders.
2Object-generated harmful factors
If the electrode base material corrodes due to high pH, then H2 gas is generated and pin holes form, but this increases the internal resistance of the electrode base material
Solution Approach 1:
The pH buffer performs preliminary anti-action by preventing the pH from rising to levels that would cause corrosion. By controlling the pH in advance, the buffer prevents the formation of H2 gas and pin holes before they can occur, thereby maintaining low internal resistance and preventing reliability degradation.
Solution Approach 2:
The invention converts the potentially harmful high pH environment into a beneficial controlled environment. By using the pH buffer to manage alkalinity, the naturally basic nature of water-based binders is transformed from a harmful factor into a controllable parameter that maintains stability without causing corrosion or increasing internal resistance.
3Quantity of substance
If alkali metal ions are present in high concentrations, then the pH increases making the electrode strongly basic, but this reduces the lifespan of the lithium battery
Solution Approach 1:
The pH buffer provides a feedback mechanism that responds to changes in alkali metal ion concentration. When the concentration of alkali ions increases and tends to raise the pH, the buffer system automatically counteracts this change, maintaining pH stability throughout the battery's operational life and preventing lifespan reduction.
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 transition metal oxides in the cathode active material composition effectively prevents aluminum corrosion, enhancing the high-rate characteristics and lifespan of lithium batteries by maintaining low internal resistance and stable pH levels.
Implementation Method 1
prevent corrosion by oxidizing aluminum and forming a protective Al2O3 layer
Data Source
AI summary
A cathode active material composition includes a cathode active material, a water-based binder, and a transition metal oxide. A cathode is prepared using the cathode active material composition. A lithium battery includes the cathode. The lithium battery has improved high-rate characteristics and lifespan characteristics by preventing an increase in internal resistance due to the corrosion of an electrode base material.