Composite Cathode Material for High-Voltage Low-Temperature Li-Ion Cells
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density, high operating voltage, and enhanced low-temperature properties.
Innovation Solution
A positive electrode active material comprising first and second particles with specific chemical compositions and particle sizes, prepared by a method involving spray drying and baking, is used to enhance the performance of rechargeable lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single positive electrode active material is used, then the battery structure is simple, but it is difficult to achieve high energy density, high operating voltage, and enhanced low-temperature properties simultaneously
Solution Approach 1:
The patent uses a composite positive electrode active material consisting of two distinct particle types: first particles with olivine structure (LiFePO4-based) providing stability and low-temperature performance, and second particles with layered structure (LiCoO2-based) providing high voltage and energy density. This composite approach enables the battery to achieve multiple performance targets simultaneously without significantly increasing structural complexity.
Solution Approach 2:
The patent applies local quality by assigning different functional characteristics to different particle types within the same electrode. The first particles (olivine structure) are optimized for structural stability and low-temperature operation, while the second particles (layered structure) are optimized for high voltage output and energy density. This localized functional differentiation allows the overall electrode to exhibit superior comprehensive performance.
2Quantity of substance
If high energy density is pursued through high capacity materials, then energy density improves, but operating voltage and low-temperature properties deteriorate
Solution Approach 1:
The patent combines two particle types with complementary properties: first particles (olivine structure) that maintain stability at low temperatures, and second particles (layered structure) that provide high lithium ion capacity. The synergistic effect of this composite material enables the battery to achieve high energy density while maintaining excellent low-temperature performance, resolving the trade-off between capacity and temperature adaptability.
3Power
If high operating voltage is achieved through high voltage materials, then voltage improves, but energy density and low-temperature properties deteriorate
Solution Approach 1:
The patent employs a composite structure where second particles (layered LiCoO2-based) provide the high operating voltage characteristics, while first particles (olivine LiFePO4-based) contribute substantial lithium ion capacity and structural stability. This composite approach enables the battery to achieve high power output through high voltage while maintaining high energy density through the capacity contribution of the first particles.
4Reliability
If particle size is reduced to improve conductivity, then conductivity improves, but manufacturing precision and structural stability worsen
Solution Approach 1:
The patent applies local quality by creating two distinct particle size distributions: first particles with controlled larger sizes (3-10 μm) that provide structural stability and ease of manufacturing, and second particles with smaller sizes (1-5 μm) that provide high conductivity. This localized size differentiation allows the electrode to achieve good electrical conductivity while maintaining structural integrity and manufacturing feasibility.
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 energy density, operating voltage, and low-temperature performance.
Implementation Method 1
drying the first mixture by spray drying
Implementation Method 2
baking the dried first mixture
Implementation Method 3
Electrical energy is generated through the oxidation and reduction reactions when lithium ions are intercalated into and deintercalated from the positive electrode and negative electrode
Data Source
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AI summary
A positive electrode active material for a rechargeable lithium battery, a method for preparing the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material are provided. The positive electrode active material includes first particles including a compound of Lia1Mnz1Fex1Tiy1B1b1PO4-c1 and having a first average particle diameter, and second particles including a compound of Lia2Niz2Mnx2C1y2Oc2 and having a second average particle diameter. The amount of the first particles is about 80 wt% to about 97.5 wt% on the basis of 100 wt% of a sum of the amount of the first particles and the amount of the second particles.