Triangular Hydroxide Cathode Precursors for High-Nickel Battery Reliability
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Solution Overview
Problem
The increasing content of nickel in lithium secondary batteries for large-scale devices, such as hybrid vehicles, leads to reliability issues with the cathode active material due to mismatch and side reactions with lithium, resulting in reduced stability and lifespan.
Innovation Solution
A cathode active material precursor is developed, comprising a composite hydroxide particle formed by aggregating primary precursor particles with a specific triangular shape, which enhances high-temperature stability and reduces the specific surface area, thereby improving the structural stability and lifespan of lithium secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the content of nickel is increased to achieve sufficient capacity and power, then the capacity and power of the lithium secondary battery are improved, but the reliability of the cathode active material deteriorates due to mismatch and side reaction with lithium
Solution Approach 1:
A coating layer comprising at least one of a metal oxide, metal hydroxide, metal carbonate, or metal oxyhydroxide is formed on the surface of the cathode active material. This coating layer acts as an intermediary barrier between the high-nickel cathode active material and lithium, preventing direct contact and side reactions while allowing ionic and electronic transport, thus maintaining both high power and reliability
2Quantity of substance
If the content of nickel is increased to achieve sufficient capacity and power, then the capacity of the lithium secondary battery is improved, but the stability of the cathode active material deteriorates
Solution Approach 1:
The coating layer serves as a protective intermediary that stabilizes the interface between the high-nickel cathode active material and the electrolyte/lithium environment. It prevents degradation reactions while maintaining lithium ion diffusion pathways, enabling high capacity with improved stability
Solution Approach 2:
The coating process modifies the surface parameters of the cathode active material without changing the bulk composition. By controlling coating thickness, composition, and structure, the material maintains its high-capacity bulk properties while gaining surface stability against degradation
Data Source
AI summary
A cathode active material precursor according to embodiments of the present invention includes a composite hydroxide particle in which primary precursor particles are aggregated. The primary precursor particles include a particle having a triangular shape in which a minimum interior angle is 30° or more and a ratio of a length of a short side relative to a length of a long side is 0.5 or more. A cathode active material and a lithium secondary having improved high temperature stability is provided using the cathode active material precursor.