Battery Electrode Slurry Dispersion to Prevent Conductive Agglomeration
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Solution Overview
Problem
Existing lithium secondary batteries face issues with agglomeration of conductive materials in the electrode mixture, leading to increased resistance and reduced lifespan and output characteristics, particularly when using Mn-rich-based positive electrode active materials.
Innovation Solution
The method involves pre-dispersing the conductive material in the electrode slurry and controlling the drying temperature to achieve uniform distribution of the conductive material, thereby reducing agglomeration and improving the electrode's resistance and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrode preparation methods are used, then manufacturing process is simple, but conductive material agglomerates leading to increased resistance and reduced battery performance
Solution Approach 1:
The conductive material is pre-dispersed in a solvent to form a uniform slurry before being mixed with the active material and binder. This preliminary dispersion action prevents agglomeration during subsequent electrode formation processes, ensuring uniform distribution and reducing resistance while maintaining simple manufacturing.
2Quantity of substance
If Mn-rich-based positive electrode active material is used, then high capacity is achieved, but manganese elution occurs causing performance degradation and shortened lifetime
Solution Approach 1:
A coating layer is applied to the Mn-rich-based positive electrode active material to serve as an intermediary barrier. This coating prevents direct contact between the manganese-containing active material and the electrolyte, thereby preventing manganese elution while allowing lithium ion transport, thus maintaining high capacity and extending battery lifetime.
3Power
If high-voltage activation process is applied to Mn-rich-based material, then high capacity characteristics are expressed, but side reactions with electrolyte increase causing performance degradation
Solution Approach 1:
The coating layer acts as an intermediary that allows the high-voltage activation process to proceed while preventing harmful side reactions. The coating is designed to be stable at high voltages, enabling the Mn-rich material to achieve high capacity characteristics without excessive manganese elution or electrolyte decomposition.
Solution Approach 2:
The coating material and structure are specifically designed to change properties at high voltages, maintaining stability and preventing side reactions while allowing the underlying Mn-rich material to undergo necessary phase transitions for high capacity expression.
Data Source
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AI summary
An electrode mixture of the present invention comprises: an electrode active material; a binder; and a conductive material. When a cross-section of the electrode mixture is imaged such that a pixel filled 100 % with a conductive material among a plurality of divided pixels is considered to be a condensed pixel and a value obtained by counting condensed pixels is considered to be the degree of agglomeration, the degree of agglomeration of a conductive material in the electrode mixture in the depth direction of the electrode mixture has a standard deviation less than 3.0. The electrode mixture as described above includes a conductive material uniformly distributed therein and thus has low electrode resistance. Therefore, the electrode mixture can improve output and lifespan properties of a lithium secondary battery to which the electrode mixture has been applied.