Dual-Particle Cathode Composition for Low-Temperature Li-Ion Output
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density, high operating voltage, and low-temperature performance.
Innovation Solution
A positive electrode active material comprising a combination of first particles (Li a1 Fe x1 B y1 PO 4-b1 ) and second particles (Li a2 Nix 2 Co y2 Al z2 O 2-b2 ) in specific weight ratios, prepared through spray drying and baking processes, to enhance conductivity and stability.
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 low-temperature performance simultaneously
Solution Approach 1:
The patent employs a composite positive electrode active material consisting of two distinct particle types: first particles with olivine structure (LiFePO4-based) providing stability and safety, and second particles with layered structure (LiCoO2-based) providing high capacity and voltage. This composite approach enables the battery to simultaneously achieve high energy density, high operating voltage, and low-temperature performance while maintaining a manageable structure through defined weight ratios (60:40 to 90:10)
Solution Approach 2:
The patent applies local quality by assigning different functional characteristics to different particle components within the positive electrode. The first particles (olivine structure) are optimized for structural stability, safety, and low-temperature performance, while the second particles (layered structure) are optimized for high capacity and operating voltage. This functional differentiation within the composite material allows each component to contribute its specific strengths to the overall battery performance
2Quantity of substance
If high nickel content is used in the layered structure to increase capacity, then energy density improves, but structural stability and low-temperature properties deteriorate
Solution Approach 1:
The patent uses a composite structure where high-nickel layered particles (providing high capacity with x2≥0.8) are combined with olivine structure particles (providing structural stability). The olivine particles act as a stabilizing matrix that prevents structural degradation of the high-nickel particles during charge-discharge cycles, while the layered particles contribute their high capacity. This composite approach enables the battery to achieve high energy density without sacrificing structural stability or low-temperature performance
Solution Approach 2:
The patent optimizes the nickel content parameter in the layered structure (x2≥0.8) to maximize capacity while maintaining compatibility with the olivine structure. By controlling the composition parameters of both particle types and their weight ratio, the patent achieves a balance between high capacity and structural stability that would not be possible with a single material system
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 properties, enhancing battery performance and capacity.
Implementation Method 1
drying the first mixture by spray drying
Implementation Method 2
baking the dried first mixture
Implementation Method 3
produces electrical energy through the oxidation and reduction reactions if 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 includes first particles of Chemical Formula 1, and second particles of Chemical Formula 2, where the first particles and the second particles are included in a weight ratio of about 80:20 to about 60:40. Also disclosed are methods for preparing the same, and rechargeable lithium batteries including the same.