Single-Crystal Multi-Element Cathode With Low Agglomeration
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Solution Overview
Problem
Existing lithium ion battery cathode materials face issues of non-uniform particle size, easy adhesion between particles, poor roundness, and high agglomeration rates, leading to poor cyclic stability and safety.
Innovation Solution
A single-crystal multiple cathode material with a rounded morphology, uniform particle size, and low agglomeration rate is produced through a process involving multiple high-temperature sintering steps and the use of dopants and coating agents, optimizing the sintering process to enhance structural stability and reduce lattice defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel content is increased to achieve high material capacity density, then energy density is improved, but cycle life and safety deteriorate due to lithium-nickel disordered arrangement and multiple phase transitions
Solution Approach 1:
The patent changes the crystal structure parameter from multi-crystal to single-crystal, which fundamentally alters the material's phase transition behavior. This parameter change eliminates multiple phase transitions during cycling, thereby maintaining high nickel content for energy density while improving cycle life and safety.
Solution Approach 2:
The patent creates a composite structure by doping the single-crystal cathode material with aluminum and coating it with lithium aluminum silicate. This composite approach stabilizes the crystal structure, preventing lithium-nickel disordered arrangement and maintaining structural integrity during cycling, thus improving reliability while preserving high energy density.
2Reliability
If single-crystal structure is designed to improve cyclic stability and thermal stability, then material stability is enhanced, but particle size uniformity and roundness deteriorate leading to agglomeration
Solution Approach 1:
The patent optimizes sintering parameters including temperature (800-1000℃), time (10-20 hours), and atmosphere (oxygen or air) to achieve uniform particle size and rounded morphology while maintaining single-crystal structure. This parameter optimization resolves the contradiction between structural stability and manufacturing precision.
Solution Approach 2:
The patent introduces aluminum as a dopant and lithium aluminum silicate as a coating agent that act as intermediaries to control particle growth during sintering. These additives promote uniform particle size distribution and rounded morphology while preserving the single-crystal structure's cyclic stability.
3Reliability
If multiple sintering steps and doping systems are optimized to reduce lattice defects and stabilize surface structure, then material stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines doping and coating processes into a single synthesis workflow with three integrated sintering steps. By merging these operations and optimizing them as a unified process, the patent achieves high material stability while controlling overall manufacturing complexity.
Solution Approach 2:
The patent performs preliminary doping with aluminum before the final sintering step, and applies lithium aluminum silicate coating during the third sintering process. These preliminary actions prepare the material structure in advance, reducing the need for additional post-processing steps and simplifying the overall manufacturing process.
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 resulting cathode material exhibits improved energy density, rate capability, cyclic stability, and safety when applied in lithium ion batteries due to its high compaction density and stable structure.
Implementation Method 1
a synthesis process needs to be optimized, and by optimizing a sintering process and a doping and coating system, lattice defects can be reduced and the surface structure of the material can be stabilized
Data Source
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AI summary
A single-crystal-type multi-element positive electrode material, and a preparation method therefor and an application thereof. The positive electrode material satisfies the following conditions: single crystal sizes DPS90, DPS10 and DPS50 of the positive electrode material, which are measured by means of SEM, satisfying the following relationship: 0.1≤B90=(DPS90-DPS10)/DPS50≤1.5; and the agglomeration rate of the positive electrode material being less than or equal to 20%, wherein DPS90 represents that 90% of the single crystal size of the positive electrode material is less than DPS90, DPS50 represents that 50% of the single crystal size of the positive electrode material is less than DPS50, and DPS10 represents that 10% of the single crystal size of the positive electrode material is less than DPS10. The single-crystal-type multi-element positive electrode material has rounded morphology, a uniform particle size, less agglomeration, less adhesion, a high compaction density and a good structural stability, and when same is applied to a lithium ion battery, the energy density, rate capability, cyclic stability and safety of the lithium ion battery can be improved.