Triangular Hydroxide Cathode Precursors 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 used in large-scale devices, leading to instability and reduced performance.
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 enhancing structural stability, thereby improving high-temperature stability and storage properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the content of nickel is increased to achieve sufficient capacity and power in large-scale devices, then the capacity and power are improved, but the reliability of the cathode active material is deteriorated due to mismatch and side reaction with lithium
Solution Approach 1:
The patent introduces a lithium composite oxide layer as an intermediary between the nickel-based cathode active material and lithium. This intermediate layer prevents direct contact and harmful interactions between nickel and lithium, thereby improving reliability while maintaining high nickel content for sufficient power output
Solution Approach 2:
The patent uses composite materials by combining nickel-based cathode active material with lithium composite oxide to create a multi-component system. This composite structure allows the nickel component to provide high power while the lithium composite oxide component ensures stability and prevents harmful reactions, resolving the contradiction between power and reliability
2Quantity of substance
If the content of nickel is increased to achieve sufficient capacity in large-scale devices, then the capacity is improved, but the reliability of the cathode active material is deteriorated due to mismatch and side reaction with lithium
Solution Approach 1:
The lithium composite oxide layer serves as a protective intermediary that allows high nickel content (0.8≤a≤0.95) to be used for sufficient capacity while preventing direct harmful reactions between nickel and lithium, thus maintaining reliability
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating lithium composite oxide with specific stoichiometry (LixA1-yByOz) where the parameters are optimized to prevent side reactions while maintaining high nickel content for sufficient capacity
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.