Al-Y Coated Nickel-Rich Cathode for Stable Cobalt-Free Li-Ion Batteries
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Solution Overview
Problem
The increasing demand for high-capacity, high-energy-density rechargeable lithium batteries is hindered by the shortage and rising cost of cobalt, a rare metal, necessitating the development of cobalt-free or low-cobalt positive electrode active materials that maintain structural stability and cycle-life characteristics, especially under high-voltage and high-temperature conditions.
Innovation Solution
A positive electrode active material comprising lithium nickel-manganese-aluminum-based composite oxide with a coating layer containing aluminum and yttrium, where the nickel content is greater than 60 mol%, and the aluminum and yttrium content in the coating layer ranges from 0.1 to 2 mol% and 0.05 to 1 mol%, respectively, is used to enhance structural stability and reduce gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cobalt-free or low-cobalt positive electrode active materials are developed to reduce cost and address supply shortage, then economic feasibility and material availability improve, but structural stability and cycle-life characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core particles contain lithium nickel-manganese-aluminum-based composite oxide with high nickel content (≥60 mol%) for capacity, while the coating layer contains aluminum and yttrium in specific ratios (Al: 0.1-2 mol%, Y: 0.05-1 mol%) to provide localized structural stability and surface protection. This allows different regions of the material to have optimized properties for their specific functions.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel-manganese-aluminum-based composite oxide core particles with an aluminum-yttrium coating layer. This composite structure integrates the high capacity characteristics of nickel-rich materials with the structural stability provided by aluminum and yttrium, achieving both economic feasibility and reliable performance.
2Quantity of substance
If high nickel content (≥60 mol%) is used in core particles to achieve high capacity, then energy density improves, but structural stability under high-voltage and high-temperature conditions worsens
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core particles contain lithium nickel-manganese-aluminum-based composite oxide with high nickel content (≥60 mol%) for capacity, while the coating layer contains aluminum and yttrium in specific ratios (Al: 0.1-2 mol%, Y: 0.05-1 mol%) to provide localized structural stability and surface protection. This allows different regions of the material to have optimized properties for their specific functions.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel-manganese-aluminum-based composite oxide core particles with an aluminum-yttrium coating layer. This composite structure integrates the high capacity characteristics of nickel-rich materials with the structural stability provided by aluminum and yttrium, achieving both economic feasibility and reliable performance.
3Reliability
If cobalt is used in traditional amounts to maintain structural stability, then reliability improves, but cost and material availability worsen
Solution Approach 1:
The patent applies the extraction principle by completely removing cobalt from the positive electrode active material composition. Instead of using cobalt-based materials like lithium cobalt oxide or nickel-cobalt-manganese composite oxide, the patent develops a cobalt-free lithium nickel-manganese-aluminum-based composite oxide system, thereby eliminating dependence on expensive and scarce cobalt while maintaining structural stability through alternative element combinations.
4Reliability
If aluminum and yttrium coating layer is applied to improve high-voltage and high-temperature characteristics, then structural stability improves, but manufacturing complexity worsens
Solution Approach 1:
The patent applies the merging principle by combining aluminum and yttrium into a single integrated coating layer applied simultaneously to the core particles. The coating layer contains both aluminum (0.1-2 mol%) and yttrium (0.05-1 mol%) together, providing multiple functions (structural stability, surface protection, high-voltage characteristic improvement) in one layer, thereby simplifying the manufacturing process compared to applying multiple separate coating layers.
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
This solution achieves high initial charge/discharge capacity, long cycle-life, and reduced gas generation under high-voltage and high-temperature conditions, while minimizing production costs and ensuring economic feasibility.
Implementation Method 1
a coating layer on a surface of the core particles and containing yttrium, wherein an aluminum content of the coating layer is about 0.1 mol % to about 2 mol %, and a yttrium content of the coating layer is about 0.05 mol % to about 1 mol %
Implementation Method 2
performing a first heat treatment to obtain a lithium nickel-manganese-aluminum-based composite oxide
Implementation Method 3
mixing a nickel-manganese-aluminum-based composite hydroxide and a lithium raw material and performing a first heat treatment to obtain a lithium nickel-manganese-aluminum-based composite oxide
Implementation Method 4
adding the lithium nickel-manganese-based composite oxide to a solution of an aluminum raw material and a yttrium raw material mixed in an aqueous solvent, followed by mixing, drying, and performing a second heat treatment
Data Source
AI summary
A positive electrode active material, a method of preparing the same, a positive electrode and a rechargeable lithium battery including the same are provided. The positive electrode active material includes a core particle including lithium nickel-manganese-aluminum-based composite oxide and a coating layer disposed on a surface of the core particles and containing aluminum and yttrium, wherein a nickel content (e.g., amount) in the core particle is greater than or equal to about 60 mol % based on 100 mol % of a total metal excluding lithium in the positive electrode active material, and an aluminum content (e.g., amount) of the coating layer is about 0.1 mol % to about 2 mol %, and a yttrium content (e.g., amount) of the coating layer is about 0.05 mol % to about 1 mol %, each based on 100 mol % of the total metal excluding lithium in the positive electrode active material.