Aluminum-Coated High-Nickel Cathode for Side-Reaction Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rechargeable lithium batteries face challenges in achieving high capacity, high energy density, and long lifespan while minimizing side reactions and maintaining safety.
Innovation Solution
A positive electrode active material composed of a lithium nickel-based transition metal composite oxide with a nickel content of 70 mol % or more and a cobalt content of 0 mol % to 0.01 mol %, combined with an aluminum-containing coating layer on the surface, is developed. This material is prepared through a method involving wet coating with an aluminum source and subsequent heat treatment at 700° C. to 750° C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel content (70 mol% or more) is used in the positive electrode active material, then capacity and energy density are improved, but lifespan and safety deteriorate
Solution Approach 1:
The patent uses a composite material structure consisting of a lithium nickel-based active material core combined with an aluminum-containing coating layer. This composite structure allows the high-nickel core to provide high capacity and energy density while the aluminum coating layer provides stability and safety, resolving the contradiction between performance and reliability.
Solution Approach 2:
The patent applies local quality by creating an aluminum-containing coating layer specifically on the surface of the lithium nickel-based active material. This localized aluminum enrichment at the surface provides protective functions (improving lifespan and safety) without affecting the high-nickel composition in the bulk material that provides high capacity and energy density.
2Reliability
If aluminum-containing coating layer is formed on the surface, then lifespan and safety are improved, but manufacturing complexity increases
Solution Approach 1:
The patent controls the aluminum source amount parameter (less than 2 mol% based on total transition metals) and heat treatment temperature parameter (700°C to 750°C) to achieve the desired aluminum-containing coating layer. By optimizing these parameters, the coating is formed effectively without requiring excessively complex manufacturing processes.
3Adaptability or versatility
If cobalt content is reduced to 0 mol% to 0.01 mol%, then cost and environmental concerns are improved, but performance stability worsens
Solution Approach 1:
The patent extracts cobalt from the lithium nickel-based active material, reducing its content to 0 mol% to 0.01 mol%. This removal of cobalt reduces cost and environmental concerns while the aluminum-containing coating layer compensates for the lost performance stability, maintaining overall battery reliability.
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 proposed solution enhances the capacity and energy density of rechargeable lithium batteries while improving their lifespan and safety features, and effectively suppresses side reactions.
Implementation Method 1
preparing a preliminary positive electrode active material by wet coating a surface of a lithium nickel-based active material with an aluminum-containing source in a first solution
Implementation Method 2
preparing a final positive electrode active material through heat treatment of the preliminary positive electrode active material, wherein the aluminum source is present in an amount of less than 2 mol % in the first solution based on the total content of transition metals in the lithium nickel-based active material and heat treatment is performed at a temperature of greater than 700° C. to 750° C.
Data Source
AI summary
A positive electrode active material for rechargeable lithium batteries, a method of preparing the same, and a secondary battery including the same are disclosed. The positive electrode active material for rechargeable lithium batteries includes a lithium nickel-based transition metal composite oxide, wherein the lithium nickel-based transition metal composite oxide has a nickel content of 70 mol % or more and a cobalt content of 0 mol % to 0.01 mol % based on the total content of transition metals (or the total content of all metals excluding lithium). The lithium nickel-based transition metal composite oxide includes a lithium nickel-based active material and an aluminum-containing coating layer formed on a surface of the lithium nickel-based active material, and the aluminum-containing coating layer has an aluminum content of 10% to 35% as measured by EDS.