Lithium Supplementing Slurry Coating for Low-Impedance Cathodes
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Solution Overview
Problem
Current lithium supplementing materials in lithium ion batteries face challenges such as high alkalinity, difficulty in dispersion, agglomeration, and gel formation in positive electrode slurries, leading to high resistance and polarization, and limited adaptability and accuracy in additive amounts.
Innovation Solution
A lithium supplementing slurry comprising a lithium supplementing material, conductive agent, and binder, with specific ratios and properties, is used to create a lithium supplementing coating on the positive electrode plate, allowing for accurate design and improved dispersion, reducing impedance and enhancing lithium supplementing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium supplementing material is directly mixed with positive electrode active substance, then lithium supplementing effect is achieved, but the positive electrode slurry becomes difficult to disperse and prone to agglomeration and gel formation
Solution Approach 1:
The patent introduces a specific solvent system (cyclic carbonate and chain carbonate in 1:1 to 1:4 volume ratio) as an intermediary medium to dissolve the lithium supplementing material before mixing with the positive electrode active substance. This solvent intermediary prevents direct agglomeration between lithium supplementing material particles and active substance particles, ensuring uniform dispersion and preventing gel formation while maintaining the lithium supplementing effect.
2Quantity of substance
If lithium supplementing material with high alkalinity is used, then lithium supplementing capacity is improved, but the slurry resistance increases and polarization occurs
Solution Approach 1:
The patent optimizes the particle size parameters of the lithium supplementing material, specifying a D50 (median particle size) range of 0.5-12 μm. By controlling the particle size within this specific range, the patent reduces slurry resistance and polarization while maintaining adequate lithium supplementing capacity. This parameter optimization balances the trade-off between supplementing capacity and electrical performance.
3Quantity of substance
If lithium oxalate is used as the lithium supplementing active substance with a catalyst, then lithium supplementing effect is achieved, but the adaptability is limited and effective storage time is short
Solution Approach 1:
The patent replaces the catalyst-based approach with a universal solvent system (cyclic carbonate and chain carbonate combination) that can effectively dissolve and disperse multiple types of lithium supplementing materials including lithium oxalate, lithium hydroxide, lithium carbonate, and lithium phosphate. This universal solvent system eliminates the need for material-specific catalysts, extending adaptability to various lithium compounds while maintaining supplementing effect and improving storage stability.
Data Source
AI summary
A lithium supplementing slurry, a positive electrode plate, and a lithium ion battery. The lithium supplementing slurry and a positive electrode slurry are separately dispersed and mixed, such that the problems that the positive electrode slurry is difficult to disperse, easy to agglomerate and gel due to direct addition of a lithium supplementing material into the positive electrode slurry are avoided; according to the design of the present disclosure, the lithium supplementing slurry formed by adding the lithium supplementing material, a conductive agent, and a binder may achieve a better dispersion effect; and after the lithium supplementing slurry is coated on a positive electrode coating, the obtained positive electrode plate is lower in impedance and more excellent in lithium supplementing effect. the additive amount of the lithium supplementing material may also be accurately calculated and the residue of the lithium supplementing material after first charging and discharging is effectively reduced.