Nickel-Based Positive Electrode Material with Lithium Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nickel-based complex oxides in lithium batteries suffer from structural instability due to high lithium deintercalation, leading to capacity deterioration and reduced thermal stability, especially when reacting with electrolyte solutions.
Innovation Solution
A lithium nickel complex oxide with a concentration gradient of lithium ions, decreasing from the surface to the core, is developed, where the lithium ions are more concentrated in the surface portion and less concentrated in the core portion, improving thermal stability and reducing capacity deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a nickel-based complex oxide is used as positive electrode active material to achieve high capacity, then the battery capacity increases, but the structure becomes unstable due to large amount of lithium deintercalation during charging
Solution Approach 1:
The patent applies local quality by creating a non-uniform lithium ion concentration distribution within the positive electrode active material particles. The surface region has a different lithium content compared to the core region, which stabilizes the crystal structure during charging-discharging cycles while maintaining high capacity. This gradient distribution prevents structural collapse that would occur with uniform high lithium content throughout the particle.
2Quantity of substance
If lithium deintercalation is increased during charging to improve capacity, then more lithium ions can be stored, but capacity deterioration occurs easily in the nickel-based complex oxide
Solution Approach 1:
The patent changes the lithium ion concentration parameter spatially within the active material particles. By creating a concentration gradient where the surface has lower lithium content and the core has higher lithium content, the material can accommodate larger lithium deintercalation during charging without suffering capacity deterioration. This parameter variation protects against structural degradation while maintaining high reversible capacity.
3Quantity of substance
If the nickel-based complex oxide reacts with electrolyte solution to increase capacity, then more lithium can be intercalated, but thermal stability is decreased
Solution Approach 1:
The patent applies local quality by creating distinct regions within the active material particles with different lithium concentrations. The surface region has reduced lithium content which decreases reactivity with the electrolyte solution, thereby improving thermal stability. Meanwhile, the core region maintains high lithium content to ensure high intercalation capacity, thus resolving the contradiction between capacity and thermal stability.
4Device complexity
If uniform lithium distribution is maintained in the positive electrode active material, then the material structure is simpler, but capacity deterioration occurs easily through charging and discharging
Solution Approach 1:
The patent deliberately creates a non-uniform lithium distribution with distinct surface and core regions having different lithium concentrations. This local quality variation, achieved through controlled synthesis methods, prevents capacity deterioration during charging-discharging cycles by reducing structural stress and preventing phase transformations that would occur with uniform high lithium content throughout the particles.
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
This distribution of lithium ions enhances the electrochemical characteristics and thermal stability of lithium batteries, reducing gas generation and maintaining high performance during charging and discharging.
Implementation Method 1
lithium ions are distributed in a concentration gradient continuously decreasing from a surface portion to a core portion of a lithium nickel complex oxide
Data Source
AI summary
A nickel (Ni)-based positive electrode active material, a method of preparing the same, and a lithium battery using the Ni-based positive electrode active material.