Coated NCM Cathode Material for High-Temperature Battery Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges with low high-temperature stability and reliability due to the instability of NCM-based lithium metal oxides, leading to side reactions with electrolytes and degradation of battery performance.
Innovation Solution
A cathode active material is developed with a lithium metal oxide particle coated by a metalloid or metal element, achieving a surface coating level (SCL) of 0.3 or more, which reduces side reactions and enhances high-temperature stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NCM-based lithium metal oxide is used as cathode active material, then production cost and capacity are improved, but high-temperature stability deteriorates
Solution Approach 1:
The patent applies composite materials by coating NCM-based lithium metal oxide particles with aluminum oxide (Al2O3) to create a composite structure. This coating layer protects the unstable NCM core from degradation at high temperatures while maintaining the high capacity and cost-effectiveness of the nickel-rich NCM material. The composite structure combines the advantages of NCM (high capacity, low cost) with the stability of aluminum oxide coating.
Solution Approach 2:
The patent applies local quality by introducing aluminum oxide specifically at the surface region of the lithium metal oxide particles rather than throughout the bulk material. The coating is applied to address the local instability at the particle surface where side reactions with electrolytes occur, while preserving the high-capacity nickel-rich composition in the interior of the particles.
2Stability of the object's composition
If coating material is introduced on surface of lithium metal oxide particle, then high-temperature stability is improved, but side reactions with electrolyte occur
Solution Approach 1:
The aluminum oxide coating acts as an intermediary layer between the lithium metal oxide particles and the electrolyte. This intermediate coating prevents direct contact and harmful side reactions between the electrolyte and the lithium metal oxide surface, while still allowing lithium ion transport. The coating mediates the interaction between the solid electrode material and the liquid electrolyte.
Solution Approach 2:
The aluminum oxide coating creates an inert protective environment around the lithium metal oxide particles. This chemically stable oxide layer forms a barrier that isolates the reactive lithium metal oxide from the electrolyte, preventing unwanted chemical reactions while maintaining the electrochemical functionality of the cathode material.
3Duration of action of stationary object
If surface coating level is increased, then high-temperature life-span is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the coating parameters by controlling the aluminum oxide coating content within a specific range (0.1-5 wt% based on lithium metal oxide weight) and applying heat treatment at controlled temperatures (300-500°C). By adjusting these parameters, the patent achieves adequate surface coating levels that improve high-temperature life-span while avoiding excessive coating that would complicate manufacturing and reduce capacity.
Solution Approach 2:
The patent applies partial coating rather than complete or excessive coating. The aluminum oxide coating is applied to provide sufficient protection (surface coating level that improves high-temperature stability) without over-coating, which would add unnecessary manufacturing complexity and reduce the active lithium metal oxide content. The coating amount is optimized to be just sufficient for protection.
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 coated cathode active material improves the high-temperature life-span and storage properties of lithium secondary batteries by minimizing side reactions with electrolytes, resulting in enhanced performance.
Implementation Method 1
a coating material formed on at least a portion of a surface of the lithium metal oxide particle
Implementation Method 2
a cathode active material capable of a reversible insertion and desorption of lithium ions
Data Source
AI summary
A cathode active material for a lithium secondary battery according to an embodiment of the present invention includes a lithium metal oxide particle containing nickel, and a coating material formed on at least a portion of a surface of the lithium metal oxide particle. The coating material includes a metalloid element or a metal element. A surface coating level of the cathode active material is 0.3 or more.