Doped Nickel Cathode Material for High-Temperature Cycle Stability
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Solution Overview
Problem
Lithium-ion secondary batteries using nickel-containing lithium composite oxides exhibit poor high-temperature cycling performance due to structural instability and cracking of the positive electrode active material.
Innovation Solution
A positive electrode active material is developed, comprising secondary particles formed by agglomeration of primary particles with a layered nickel-containing lithium composite oxide that includes a doping element. This material is designed to maintain a maximum lattice shrinkage rate of ≤2.69% in the a-axis direction and ≤2.75% in the c-axis direction during charging from an 11% delithiated state to a 78% delithiated state at a rate of 0.1C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-containing lithium composite oxide is used as positive electrode active material, then energy density and capacity performance are improved, but high-temperature cycling performance deteriorates due to structural instability and cracking
Solution Approach 1:
The patent applies parameter changes by precisely controlling the lattice shrinkage rate in the a-axis direction and swelling rate in the c-axis direction to specific ranges (Δa max ≤ 2.69% and Δc max ≤ 2.75%). This parameter control prevents excessive structural deformation during charging, thereby improving high-temperature cycling performance while maintaining high capacity performance from nickel-containing lithium composite oxide.
Solution Approach 2:
The patent uses composite materials by forming secondary particles through agglomeration of multiple primary particles. This composite structure enhances structural stability and prevents cracking during high-temperature cycling, while the nickel-containing lithium composite oxide maintains its high energy density and capacity performance.
2Quantity of substance
If nickel-containing lithium composite oxide is used as positive electrode active material, then energy density is improved, but structural stability deteriorates leading to particle cracking
Solution Approach 1:
The patent applies parameter changes by precisely controlling the lattice shrinkage rate in the a-axis direction and swelling rate in the c-axis direction to specific ranges (Δa max ≤ 2.69% and Δc max ≤ 2.75%). This parameter control prevents excessive structural deformation during charging, thereby improving high-temperature cycling performance while maintaining high capacity performance from nickel-containing lithium composite oxide.
Solution Approach 2:
The patent uses composite materials by forming secondary particles through agglomeration of multiple primary particles. This composite structure enhances structural stability and prevents cracking during high-temperature cycling, while the nickel-containing lithium composite oxide maintains its high energy density and capacity performance.
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 proposed positive electrode active material enhances the structural stability and capacity of lithium-ion secondary batteries, significantly improving their high-temperature cycling performance and energy density.
Implementation Method 1
when the positive electrode active material is charged from an 11% delithiated state to a 78% delithiated state at a rate of 0.1C, a lattice of the primary particles has a maximum shrinkage rate satisfying Δamax ≤ 2.69% in an a-axis direction, and a maximum swelling rate satisfying Δcmax ≤ 2.75% in a c-axis direction
Implementation Method 2
Lithium-ion secondary batteries are rechargeable batteries that operate mainly depending on migration of lithium ions between a positive electrode and a negative electrode
Data Source
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AI summary
A positive electrode active material and a preparation method thereof, a positive electrode plate, a lithium-ion secondary battery (5), and a battery module (4), a battery pack (1), and apparatus containing the lithium-ion secondary battery (5) are provided. The positive electrode active material includes secondary particles formed by agglomeration of primary particles, where the primary particles include a layered nickel-containing lithium composite oxide, and the nickel-containing lithium composite oxide includes a doping element; and when the positive electrode active material is charged from an 11% delithiated state to a 78% delithiated state at a rate of 0.1C, a lattice of the primary particles has a maximum shrinkage rate satisfying Δamax ≤ 3.00% in an a-axis direction, and a maximum swelling rate satisfying Δcmax ≤ 3.02% in a c-axis direction.