Titanium-Coated Cathode Material to Prevent Electrode Paste Gelation
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Solution Overview
Problem
Current methods for producing non-aqueous electrolyte secondary batteries using lithium-nickel composite oxide as a positive electrode active material face challenges in suppressing gelation of the positive electrode mixture paste, which can lead to reduced battery capacity and thermal stability issues, while attempts to mitigate gelation often increase material costs and decrease battery performance.
Innovation Solution
A positive electrode active material is developed by incorporating a titanium compound-containing coating layer on lithium-nickel composite oxide particles with boron, which suppresses gelation and enhances battery capacity, achieved through a method involving the mixing of nickel, lithium, and boron compounds, followed by firing and coating with a titanium alkoxide solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-nickel composite oxide is used as positive electrode active material, then battery voltage and capacity are improved, but gelation of positive electrode mixture paste occurs
Solution Approach 1:
A coating layer containing titanium compound is applied on the surface of lithium-nickel composite oxide particles. This coating layer acts as an intermediary between the active material and the paste components, preventing direct harmful interactions that cause gelation while maintaining electrochemical performance. The titanium compound coating suppresses the reaction between excessive lithium and water in the paste, thereby preventing pH increase and gelation.
Solution Approach 2:
The surface properties of lithium-nickel composite oxide particles are modified by coating with titanium compound. This changes the surface chemistry parameters, reducing the reactivity of surface lithium with moisture in the paste environment. The coating alters the interaction parameters between the active material and binder/solvent system, preventing unwanted polymerization and gelation.
2Quantity of substance
If excessive lithium is added to increase battery capacity, then battery voltage is improved, but gelation occurs more frequently
Solution Approach 1:
The titanium compound coating serves as a protective intermediary that allows high lithium content to be incorporated without causing paste gelation. The coating prevents direct contact between excessive lithium and water in the paste, enabling the use of lithium-rich compositions while maintaining good paste processability and coating characteristics.
3Reliability
If conventional methods are used to suppress gelation, then paste stability is improved, but material cost increases and battery performance decreases
Solution Approach 1:
A thin coating layer of titanium compound is applied on the particle surface, using a small amount of coating material to achieve the suppression of gelation. This approach is more cost-effective than adding large amounts of other additives, and the coating layer is sufficient to provide the needed protection without excessive material cost.
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 approach effectively suppresses gelation of the positive electrode mixture paste and improves battery capacity, allowing for high initial discharge capacity and stability, while maintaining the inherent characteristics of the lithium-nickel composite oxide, suitable for industrial-scale production.
Implementation Method 1
the positive electrode active material can suppress gelation of a positive electrode mixture paste
Implementation Method 2
The positive electrode active material for nonaqueous electrolyte secondary batteries according to the present invention can increase the capacity of a battery
Data Source
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AI summary
An object is to provide a positive electrode active material capable of achieving both higher battery capacity and suppression of gelation of a positive electrode mixture paste at the time of battery production at a high level. A positive electrode active material for non-aqueous electrolyte secondary batteries includes a lithium-nickel composite oxide particle and a coating layer attached to at least a part of a surface of the particle. The lithium-nickel composite oxide particle contains boron therein, and the coating layer contains a titanium compound.