Composite Cathode Material Balancing Nickel Energy Density and Cycle Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium composite oxides with high nickel content in rechargeable lithium batteries suffer from reduced lifespan and stability, limiting their energy density and capacity retention.
Innovation Solution
A positive electrode active material comprising a blend of first particles with a spinel crystal structure, second particles with a layered crystal structure, and third particles with a layered crystal structure, where the first particles have a higher weight ratio, enhancing structural stability and conductivity, while the second and third particles with higher nickel content improve energy density and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel content lithium composite oxide is used as positive active material, then energy density is improved, but lifespan and stability are reduced
Solution Approach 1:
The patent uses a composite material system consisting of three types of lithium composite oxides with different crystal structures (spinel and layered) and different nickel contents. This composite approach allows the battery to achieve high energy density from high-nickel particles while maintaining stability through spinel and lower-nickel particles, thereby resolving the contradiction between energy density and reliability
Solution Approach 2:
The patent applies local quality by creating particles with non-uniform nickel distribution and different crystal structures in different regions. High-nickel layered oxide provides energy density in specific regions, while spinel structure provides stability in other regions, allowing both high energy density and long lifespan to coexist within the same material system
2Quantity of substance
If high nickel content is used to improve energy density, then capacity is increased, but capacity retention deteriorates
Solution Approach 1:
The composite material system combines three types of lithium composite oxides where high-nickel layered oxide (second and third particles) provides high capacity, while spinel structure (first particles) and lower-nickel content maintain capacity retention over cycles. This composite approach resolves the contradiction between achieving high capacity and maintaining capacity retention
3Power
If nickel content is increased to enhance energy density, then output is improved, but structural stability is reduced
Solution Approach 1:
The patent implements local quality by distributing different crystal structures and nickel contents throughout the material. Spinel structure particles provide structural stability in regions where it is needed, while high-nickel layered oxide particles provide high output in other regions, allowing the material to exhibit both high power and structural stability simultaneously
Solution Approach 2:
The composite material system uses the complementary properties of spinel and layered crystal structures. Spinel provides structural stability and conductivity, while layered high-nickel oxide provides high output and energy density. This composite approach resolves the contradiction between power and structural stability
Data Source
AI summary
Disclosed are positive electrode active materials and rechargeable lithium batteries including the positive electrode active materials. The positive electrode active materials comprise a first particle including a first lithium composite oxide having a spinel crystal structure, a second particle including a second lithium composite oxide having a layered crystal structure, and a third particle including a third lithium composite oxide having a layered crystal structure. An average particle diameter of the second particle is greater than an average particle diameter of the third particle. The first particle has a first weight ratio relative to a total weight of the first, second, and third particles. The second particle has a second weight ratio relative to the total weight. The third particle has a third weight ratio relative to the total weight. The first weight ratio is greater than a sum of the second weight ratio and the third weight ratio.