Bimodal LiFePO4 Cathode Material for Energy Density and Cold Performance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high capacity, improved low-temperature characteristics, and long lifespan while maintaining high energy density.
Innovation Solution
A positive electrode active material composed of first and second particles, where the first particle is a polycrystalline olivine-based lithium iron phosphate with a larger average diameter, and the second particle is a smaller nano-sized particle, both with specific chemical compositions and prepared through distinct methods, are mixed to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If only large particles are used in the positive electrode active material, then energy density is improved, but low-temperature characteristics and capacity deteriorate
Solution Approach 1:
The positive electrode active material is segmented into two distinct particle size ranges: large particles (3 μm to 10 μm) for energy density and small particles (0.1 μm to 2 μm) for low-temperature performance. This segmentation allows each particle size to fulfill its specific functional role without compromising the other.
Solution Approach 2:
Different regions of the electrode are assigned different particle sizes based on their functional requirements. Large particles dominate the bulk structure for high energy density, while small particles are distributed throughout to ensure good low-temperature characteristics and capacity.
2Reliability
If only small particles are used in the positive electrode active material, then low-temperature characteristics and capacity are improved, but energy density deteriorates
Solution Approach 1:
The positive electrode active material is segmented into two distinct particle size ranges: large particles (3 μm to 10 μm) for energy density and small particles (0.1 μm to 2 μm) for low-temperature performance. This segmentation allows each particle size to fulfill its specific functional role without compromising the other.
Solution Approach 2:
Different regions of the electrode are assigned different particle sizes based on their functional requirements. Large particles dominate the bulk structure for high energy density, while small particles are distributed throughout to ensure good low-temperature characteristics and capacity.
3Quantity of substance
If only large particles are used in the positive electrode active material, then energy density is improved, but capacity and lifespan deteriorate
Solution Approach 1:
The positive electrode active material is segmented into two distinct particle size ranges: large particles (3 μm to 10 μm) for energy density and small particles (0.1 μm to 2 μm) for low-temperature performance. This segmentation allows each particle size to fulfill its specific functional role without compromising the other.
Solution Approach 2:
Different regions of the electrode are assigned different particle sizes based on their functional requirements. Large particles dominate the bulk structure for high energy density, while small particles are distributed throughout to ensure good low-temperature characteristics and capacity.
4Reliability
If a bimodal particle size distribution is implemented, then low-temperature characteristics and capacity are improved, but device complexity increases
Solution Approach 1:
The positive electrode active material is segmented into two distinct particle size ranges: large particles (3 μm to 10 μm) for energy density and small particles (0.1 μm to 2 μm) for low-temperature performance. This segmentation allows each particle size to fulfill its specific functional role without compromising the other.
Solution Approach 2:
The particle size parameter is changed to create a bimodal distribution with specific ranges: large particles (3 μm to 10 μm) and small particles (0.1 μm to 2 μm). This parameter optimization achieves the desired performance balance while maintaining manufacturability.
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 battery exhibits high capacity, improved low-temperature characteristics, and extended lifespan with enhanced energy density.
Implementation Method 1
Electrical energy is produced (generate) through oxidation and reduction reactions as the lithium ions are intercalated and deintercalated into/from the positive electrode and the negative electrode.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A positive electrode active material for a rechargeable lithium battery, a preparation method of the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material are disclosed. The positive electrode active material includes a first particle containing a compound represented by Formula 1 and having a first average particle diameter and a second particle containing a compound represented by Formula 2 and having a second average particle diameter smaller than the first average particle diameter, wherein an amount of the first particle is equal to or greater than an amount of the second particle. A more detailed description of Formulae 1 and 2 is provided in the present disclosure.