Over-Lithiated Nickel Composite Oxide for Lithium Battery
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Solution Overview
Problem
Rechargeable lithium batteries face challenges with positive active materials that have high manufacturing costs, unstable structures, low thermal stability, and the generation of oxygen gas during charge and discharge, which affects capacity and efficiency.
Innovation Solution
A nickel-based composite oxide with over lithiated oxide and non-continuous lithium nickel cobalt manganese oxide coatings is developed, providing high electrical conductivity and suppressing oxygen gas generation and electrolyte reactions, thereby enhancing thermal stability and battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiCoO2 is used as positive active material, then battery performance is improved, but manufacturing cost increases and supply stability deteriorates due to cobalt scarcity
Solution Approach 1:
The patent changes the chemical composition parameters by replacing cobalt with nickel and manganese in the positive active material, creating LiNi0.8Co0.1Mn0.1O2 with modified atomic ratios. This parameter change maintains battery performance while reducing cobalt content to address cost and supply stability issues
Solution Approach 2:
The patent creates a composite material system by combining multiple elements (Li, Ni, Co, Mn) in specific ratios within the layered oxide structure. The composite nature of LiNi0.8Co0.1Mn0.1O2 allows optimization of both performance and cost by distributing functions across different elements
2Quantity of substance
If nickel-based positive active material is used for high capacity and high voltage, then battery capacity increases, but structural stability deteriorates and thermal stability decreases due to electrolyte reaction
Solution Approach 1:
The patent optimizes the atomic ratios of Ni, Co, and Mn in the layered oxide structure, specifically using LiNi0.8Co0.1Mn0.1O2 with controlled composition parameters. This parameter optimization enhances both capacity and structural stability by balancing the high-capacity nickel with stabilizing cobalt and manganese
Solution Approach 2:
The patent employs a composite layered oxide structure where nickel, cobalt, and manganese work synergistically. The composite material design allows the high-capacity nickel component to be stabilized by the structural support from cobalt and manganese, preventing degradation while maintaining high voltage performance
3Quantity of substance
If over lithiated oxide is used to increase capacity, then battery capacity increases, but oxygen gas generation increases and initial efficiency decreases due to irreversible lithium ion reaction
Solution Approach 1:
The patent carefully controls the lithiation level and composition ratios in the over-lithiated oxide structure, using specific atomic weight ratios of Ni:Mn (1:1 to 2:1) in the over lithiated oxide portion. This parameter control enables capacity enhancement while suppressing excessive oxygen evolution and improving initial efficiency
Solution Approach 2:
The patent creates a composite structure with distinct regions having different compositions and functions. The over lithiated oxide portions provide high capacity while the lithium nickel cobalt manganese oxide portions suppress oxygen generation, with each region optimized for its specific function
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 solution results in a rechargeable lithium battery with improved high-capacity, high-voltage performance and thermal stability, achieved through the specific atomic weight ratios and preparation method of the nickel-based composite oxide.
Implementation Method 1
a positive electrode including a positive active material capable of intercalating/deintercalating lithium ions
Implementation Method 2
the over lithiated oxides (which may include Mn oxides) release lithium ions at a voltage of greater than or equal to about 4.55 V
Data Source
AI summary
A positive active material for a rechargeable lithium battery includes a nickel-based composite oxide represented by the following Chemical Formula 1, wherein the nickel-based composite oxide includes an over lithiated oxide and non-continuous portions of a lithium nickel cobalt manganese oxide on a surface of the over lithiated oxide.LiaNibCocMndO2 Chemical Formula 1where 1<a<1.6, 0.1<b<0.7, 0.1<c<0.4, and 0.1<d<0.7.