Oxalic Acid Cathode Slurry for Viscosity and Agglomeration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nickel-rich lithium transition metal oxides used in positive electrodes for secondary batteries face issues with slurry stability and agglomeration, limiting their application to medium- to large-sized models such as vehicles, and there is a need for improved viscosity control and agglomeration prevention in the slurry.
Innovation Solution
A positive electrode slurry is formulated with oxalic acid to control viscosity and prevent agglomeration, incorporating specific amounts of oxalic acid and an overcharge inhibitor, along with a conductive material and binder, to achieve a viscosity range of 4000 cp to 15000 cp at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If nickel-rich lithium transition metal oxide is used as positive electrode active material, then high discharge capacity is achieved, but slurry phase stability is reduced
Solution Approach 1:
Dextrin is introduced as an intermediary substance to mediate between the nickel-rich positive electrode active material and the slurry components. The dextrin forms a protective coating around the active material particles, preventing direct interaction that causes instability while maintaining the high capacity characteristics of the nickel-rich material.
Solution Approach 2:
The invention creates a composite slurry system combining nickel-rich lithium transition metal oxide with dextrin and other slurry components. This composite approach allows the beneficial high-capacity properties of the nickel-rich material to be preserved while the dextrin provides structural stability and prevents aggregation, achieving both high power and stability.
2Power
If nickel-rich lithium transition metal oxide is used as positive electrode active material, then high discharge capacity is achieved, but agglomeration occurs in slurry
Solution Approach 1:
Dextrin serves as a steric barrier and intermediary layer between nickel-rich active material particles, preventing them from aggregating into large clumps. The dextrin molecules adsorb onto the particle surfaces and create physical separation, maintaining uniform particle distribution and preventing the formation of large agglomerates that would harm electrode performance.
Solution Approach 2:
The invention modifies the slurry's rheological and surface chemical parameters by adding dextrin, which changes the interaction forces between particles. This parameter change transforms the system from one prone to aggregation to one with stable dispersion, allowing the high-capacity nickel-rich material to be processed effectively.
3Adaptability or versatility
If nickel-rich lithium transition metal oxide is used as positive electrode active material, then application to small-sized batteries is feasible, but application to medium- to large-sized batteries is limited
Solution Approach 1:
Dextrin acts as a stabilizing intermediary that enables the slurry to maintain its properties across different scales. The dextrin ensures uniform mixing and stable suspension of the active material, which is critical for large-sized batteries where homogeneous composition throughout the entire electrode is essential for consistent performance and safety.
Solution Approach 2:
The dextrin-based slurry formulation creates a universal system that can be adapted to various battery sizes from small to large. The same slurry composition and processing approach works across different scales, eliminating the limitation that previously restricted nickel-rich materials to only small-sized battery applications.
Data Source
AI summary
Provided are a positive electrode slurry for preparing a positive electrode for a lithium secondary battery,the positive electrode slurry including a positive electrode active material, a conductive material, a binder, overcharge inhibitor, oxalic acid, and a solvent,wherein the overcharge inhibitor is included in an amount of 1 part by weight to 2 parts by weight, based on 100 parts by weight of the total solid content of the positive electrode active material, the conductive material, and the binder of the positive electrode slurry,the oxalic acid is included in an amount of 0.1 part by weight to 0.7 parts by weight, based on 100 parts by weight of the total solid content of the positive electrode active material, the conductive material, and the binder of the positive electrode slurry, andthe positive electrode slurry has a viscosity of 4000 cp to 15000 cp at room temperature; a preparation method thereof; a positive electrode for a secondary battery; and a secondary battery.