Phosphate Ester Lithium Supplement Slurry to Prevent Electrode Gelation
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Solution Overview
Problem
In lithium-ion batteries, irreversible lithiation of the negative electrode during the first charge-and-discharge cycle leads to a decrease in ion concentration of the electrolyte solution, impairing the charge and discharge performance and capacity due to the formation of an SEI film on the negative electrode surface and loss of lithium from the positive electrode.
Innovation Solution
A lithium supplement slurry is introduced, comprising a phosphate ester compound as a solvent and lithium nitride as an additive, which does not react at normal temperatures, preventing gelation and ensuring uniform distribution and high decomposition rates, thereby enhancing lithium supplementation in the positive electrode slurry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium supplement additive is added to the positive electrode slurry to compensate for lithium loss, then the capacity and energy density of the battery are improved, but the slurry becomes prone to gelation and difficult to process
Solution Approach 1:
The patent changes the chemical composition parameters of the slurry by introducing a phosphate ester compound as a specific solvent that prevents gelation. This parameter change allows the lithium supplement additive to be incorporated without causing the harmful gelation effect, thus maintaining both improved lithium capacity and manufacturability
Solution Approach 2:
The phosphate ester compound acts as an intermediary substance that mediates between the lithium supplement additive and the slurry matrix. It prevents direct harmful interactions that would cause gelation, enabling the lithium supplement to function properly while maintaining slurry processability
2Stability of the object's composition
If the lithium supplement additive reacts with the solvent to form gel, then the slurry viscosity increases, but the coating uniformity and electrochemical performance deteriorate
Solution Approach 1:
The patent modifies the chemical parameters of the slurry system by selecting a phosphate ester compound with specific properties that prevent gel formation. This parameter change maintains slurry stability while ensuring uniform coating quality and electrochemical performance
3Ease of manufacture
If conventional solvents are used in the positive electrode slurry, then the slurry can be easily prepared, but the lithium supplement additive reacts to form gel and reduces battery performance
Solution Approach 1:
The patent changes the solvent parameter from conventional options to a phosphate ester compound, which fundamentally alters the chemical behavior of the slurry system. This parameter change eliminates the harmful reaction between the lithium supplement additive and solvent, maintaining both ease of manufacture and battery performance reliability
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 solution increases energy density and improves electrochemical performance by maintaining slurry stability and uniformity, ensuring high decomposition rates of the lithium supplement additive, thus enhancing the capacity and performance of the secondary battery.
Implementation Method 1
the decomposition rate of the lithium supplement additive in the positive electrode plate is relatively high, so the capacity exerted by the lithium supplement additive is relatively high
Data Source
AI summary
This application provides a lithium supplement slurry, a positive electrode slurry, a secondary battery, a secondary battery preparation method, and an electrical device. The lithium supplement slurry includes a lithium supplement additive and a phosphate ester compound. The lithium supplement slurry uses a phosphate ester compound as a solvent. The phosphate ester compound is stable at a normal temperature, and does not react with the lithium supplement additive. Therefore, in a positive electrode slurry that uses the phosphate ester compound for supplementing lithium, the phosphate ester compound does not make the positive electrode slurry prone to gel, but makes the slurry meet performance requirements on an industrial mass-produced slurry, and makes it easy to apply the slurry to form a coating layer. In addition, the phosphate ester compound is of low toxicity and high safety in production.