Composite Cathode Material Balancing Battery Capacity and Stability
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density and efficiency while maintaining economic viability.
Innovation Solution
A positive electrode active material comprising a combination of first particles with an olivine structure, second particles with a spinel structure, and third particles with a layered structure, along with a conductive material and binder, enhances the energy density and efficiency of rechargeable lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-type positive electrode active material is used, then the manufacturing process is simple, but the energy density and operating voltage are limited
Solution Approach 1:
The patent employs a composite positive electrode active material consisting of three distinct particle types: olivine-structured particles (LiFePO4-based) providing stability and safety, spinel-structured particles (LiMn2O4-based) providing high operating voltage, and layered-structured particles (LiCoO2-based) providing high capacity. This multi-structure composite approach enables the electrode to achieve both high energy density and high operating voltage while maintaining structural integrity during charge-discharge cycles.
2Quantity of substance
If high-capacity materials are used to increase energy density, then the battery capacity improves, but the structural stability and cycle life deteriorate
Solution Approach 1:
The patent assigns different functional roles to different particle types within the composite: olivine particles serve as the stable backbone providing structural integrity and safety, spinel particles provide high-voltage pathways, and layered particles contribute high capacity. This local functional differentiation allows each component to optimize its specific role while collectively achieving high energy density with maintained stability.
Solution Approach 2:
By combining three crystal structures with complementary properties, the composite material achieves a balance between capacity and stability. The olivine structure's inherent stability prevents catastrophic degradation, while the spinel and layered structures contribute high-capacity pathways, resulting in a material that maintains structural integrity even at high capacity levels.
3Power
If high-voltage materials are used to increase operating voltage, then the energy density improves, but the material stability and safety deteriorate
Solution Approach 1:
The olivine-structured particles act as an intermediary stabilizing component within the composite. These particles have inherently high structural stability and safety characteristics, serving as a buffer that prevents the high-voltage spinel and high-capacity layered particles from undergoing dangerous structural transformations during operation, thus maintaining overall battery safety.
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 active material configuration results in rechargeable lithium batteries with improved energy density and efficiency, offering an economical solution for high-performance battery applications.
Implementation Method 1
a rechargeable lithium battery is a battery including a positive electrode and a negative electrode containing active materials capable of intercalation and deintercalation of lithium ions
Implementation Method 2
A rechargeable lithium battery produces electrical energy through the oxidation and reduction reactions when lithium ions are intercalated into and deintercalated from the positive electrode and negative electrode
Data Source
AI summary
Disclosed are positive electrode active materials for a rechargeable battery, positive electrodes including the positive electrode active materials, and rechargeable lithium batteries including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles comprising a compound having a spinel structure, and third particles comprising a compound having a layered structure. The first particles and the second particles constitute a main active material, and the amount of the main active material is about 80 parts by weight to about 90 parts by weight based on 100 parts by weight of the positive electrode active material.