Triangular Cathode Precursor Structure for High-Temperature Stability
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Solution Overview
Problem
The reliability of nickel-based cathode active materials in lithium secondary batteries is deteriorated due to mismatch and side reactions with lithium, especially when the nickel content is increased to enhance capacity and power, leading to stability issues.
Innovation Solution
A cathode active material precursor is developed with composite hydroxide particles formed from primary precursor particles having a triangular shape and specific aspect ratios, which are aggregated to form secondary particles, reducing the specific surface area and increasing contact area, thereby improving structural stability and high-temperature performance.
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:
The patent uses a composite hydroxide structure where primary precursor particles are aggregated to form secondary composite particles. This composite structure allows high nickel content (0.8≤α≤0.95 in NiαCOβMγ(OH)z) while maintaining reliability through the aggregated particle morphology with specific surface area of 1.5 m2/g or less, reducing harmful surface reactions.
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 cathode active material precursor is segmented into primary precursor particles that are aggregated to form secondary composite particles. This segmentation allows high nickel content (0.8≤α≤0.95) while the aggregated structure with specific surface area of 1.5 m2/g or less provides stability by reducing surface exposure and preventing composition degradation.
3Ease of manufacture
If a conventional precursor structure is used, then the manufacturing process is simple, but the specific surface area is large leading to poor stability and high-temperature performance
Solution Approach 1:
The patent performs preliminary action by controlling the co-precipitation process to form primary precursor particles with specific morphology (triangular shape with minimum interior angle of 30° or more and short side/long side ratio of 0.5 or more) before final cathode material synthesis. This preliminary particle formation ensures low specific surface area (1.5 m2/g or less) and high stability while maintaining manufacturing feasibility through a single co-precipitation step.
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 composite hydroxide particles enhance the stability and high-temperature life-span of lithium secondary batteries by reducing surface area and increasing contact between particles, resulting in improved mechanical and electrical stability.
Implementation Method 1
A cathode active material precursor includes a composite hydroxide particle in which primary precursor particles are aggregated
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.