Positive Electrode Slurry Composition to Prevent Gelation
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Solution Overview
Problem
Lithium rechargeable batteries face challenges with gelation phenomena during the fabrication of positive electrodes using lithium nickel-based or manganese-based composite oxides, leading to reduced battery capacity and performance due to non-reacted lithium compounds and high alkalinity, which existing methods fail to adequately address.
Innovation Solution
Incorporating a positive electrode active material layer with a lithium compound, a binder, and an antigelling agent containing sulfonate groups, such as naphthaline-sulfonic acid, to prevent gelation, while maintaining high capacity and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel-based or manganese-based composite oxide is used as positive electrode active material, then battery capacity is improved, but gelation phenomenon occurs during fabrication
Solution Approach 1:
A water-soluble polymer is introduced as an intermediary substance between the lithium nickel-based or manganese-based composite oxide and the slurry components. This polymer mediates the interaction by forming a protective layer on the oxide surface, preventing direct harmful reactions while maintaining electrochemical activity, thus eliminating gelation without sacrificing battery capacity.
Solution Approach 2:
The invention changes the chemical parameters of the positive electrode slurry by adjusting the composition and concentration of the water-soluble polymer. This parameter modification alters the slurry's chemical environment to be compatible with high-capacity lithium nickel-based or manganese-based composite oxides, preventing gelation while preserving the desired battery capacity.
2Ease of manufacture
If non-reacted lithium compound remains on the surface, then manufacturing process is simplified, but gelation problem occurs and battery characteristics degrade
Solution Approach 1:
The water-soluble polymer acts as a mediator that allows non-reacted lithium compounds to remain on the oxide surface without causing gelation. The polymer forms a protective interface that prevents harmful interactions between the lithium compounds and other slurry components, maintaining both manufacturing simplicity and battery performance.
3Ease of operation
If lithium carbonate forms by reacting with CO2, then atmospheric reaction is natural, but gas is produced at high temperature degrading battery characteristics
Solution Approach 1:
The water-soluble polymer serves as a protective intermediary that covers the lithium carbonate surface, preventing thermal decomposition and gas evolution during battery operation. This intermediary layer allows the lithium carbonate to form naturally from atmospheric CO2 reaction while preventing the harmful gas production that would otherwise occur at high temperatures.
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 effectively prevents gelation, maintains high battery capacity, and ensures stable electrochemical properties by controlling viscosity and preventing gas production, thereby enhancing the manufacturing process and battery reliability.
Implementation Method 1
an antigelling agent which contains a sulfonate group (—SO3H—)
Implementation Method 2
a positive electrode active material which includes a lithium compound that intercalates and deintercalates a lithium ion
Data Source
AI summary
The present invention provides a positive electrode for a lithium rechargeable battery, a lithium rechargeable battery including the same, and a method of fabricating the lithium rechargeable battery. An antigelling agent is added in a positive electrode slurry to prevent gelation, and the positive electrode of the present invention is made with the antigelling agent added positive electrode slurry. During fabrication of the positive electrode by using a lithium nickel-based or manganese-based composite oxide for a positive electrode active material, gelation is prevented. A lithium rechargeable battery made with the positive electrode of the present invention shows a high capacity and excellent stability and reliability.