Lithium Metal Composite Oxide Powder for Battery Cathodes
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Solution Overview
Problem
Lithium metal composite oxides with a layered structure face challenges in achieving excellent charge-discharge cycle ability and initial charging and discharging efficiency, particularly in reducing initial resistance for use in lithium secondary batteries, especially for in-vehicle applications.
Innovation Solution
A lithium metal composite oxide powder with a layered structure is developed, characterized by specific compositional and structural parameters, including a ratio of crystallite sizes, primary to secondary particle area ratios, and calcining conditions to minimize rock-salt structure formation and enhance lithium ion intercalation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium metal composite oxide with layered structure is used as positive electrode active material, then charge and discharge capacity is improved, but initial resistance is high and charge-discharge cycle ability is insufficient
Solution Approach 1:
The invention changes the chemical composition parameters by introducing fluorine substitution at specific ratios (0.01 ≤ x ≤ 0.10 in Li1-xMn2-xNixF1+xO4 structure) and controls crystallite size parameters (10-50 nm range) to simultaneously improve initial resistance and charge-discharge cycle stability while maintaining high capacity
Solution Approach 2:
The invention creates a composite spinel structure combining Li, Mn, Ni, and F elements in a specific configuration (Li1-xMn2-xNixF1+xO4) that integrates the benefits of high capacity from layered structures with the stability of spinel structures, achieving both high power and reliability
2Use of energy by moving object
If lithium metal composite oxide with layered structure is used, then energy density is improved, but initial resistance reduction is insufficient
Solution Approach 1:
The invention optimizes compositional parameters (fluorine content x) and structural parameters (crystallite size, surface area) to reduce initial resistance while preserving the high energy density characteristics of lithium metal composite oxides, achieving both low resistance and high energy density simultaneously
3Quantity of substance
If conventional lithium metal composite oxide is used for in-vehicle batteries, then battery capacity is sufficient, but cycle life and efficiency are insufficient
Solution Approach 1:
The invention modifies compositional parameters (introducing fluorine substitution) and structural parameters (controlling crystallite size to 10-50 nm) to enhance cycle life and efficiency while maintaining sufficient battery capacity for in-vehicle applications
Solution Approach 2:
The invention performs preliminary surface treatment and crystallite size control before battery assembly to pre-establish stable surface properties that prevent degradation during cycling, thereby extending cycle life while maintaining capacity
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 optimized lithium metal composite oxide powder exhibits improved charge-discharge cycle ability and initial charging and discharging efficiency, effectively reducing initial resistance, making it suitable for high-performance lithium batteries in electric vehicles and hybrid electric vehicles.
Implementation Method 1
During charging, lithium is eluted from a positive electrode as an ion, moves to a negative electrode, and is intercalated to the negative electrode
Implementation Method 2
During discharging, the lithium ion returns to the positive electrode from the negative electrode
Data Source
AI summary
Provided is a lithium metal composite oxide (powder) having a layered structure, which is capable of exhibiting excellent characteristics in both charge-discharge cycle ability and initial charging and discharging efficiency, and is capable of effectively reducing initial resistance, when being used in a positive electrode of a lithium battery. The lithium metal composite oxide (powder) comprises an amount of S which is less than 0.10% by mass of the lithium metal composite oxide powder, a ratio of a crystallite size of a (003) plane to a crystallite size of a (110) plane which is equal to or greater than 1.0 and less than 2.5, and a ratio of a primary particle area to a secondary particle area of 0.004 to 0.035.