Cathode Active Material Composition for Higher Volumetric Energy Density
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Solution Overview
Problem
Lithium-ion batteries using olivine-type and lithium-rich manganese-based positive electrode materials face issues with low energy density, poor high-temperature cycle performance, and low electrical conductivity, limiting their application and efficiency.
Innovation Solution
A positive electrode active material composition comprising specific particle size distributions and doping of lithium manganese iron phosphate and lithium-rich manganese-based materials, combined with a carbon coating, to enhance conductivity and compaction density, thereby improving the rate and cycle performance of lithium-ion secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium iron phosphate and lithium-rich manganese-based materials are used as positive electrode materials, then production cost is reduced and theoretical capacity is increased, but energy density and high-temperature cycle performance deteriorate
Solution Approach 1:
The patent uses composite materials by combining lithium iron phosphate (olivine-type) and lithium-rich manganese-based materials in a specific particle size distribution. This composite structure allows the positive electrode to achieve both low production cost and improved high-temperature cycle performance, as the two materials complement each other's strengths and weaknesses
Solution Approach 2:
The patent applies local quality by creating a specific particle size distribution where smaller particles (0.5-5 μm) of lithium iron phosphate are combined with larger particles (5-20 μm) of lithium-rich manganese-based materials. This local differentiation in particle size and material composition optimizes both cost and performance characteristics in different regions of the electrode
2Ease of manufacture
If lithium-rich manganese-based materials are used to achieve high discharge specific capacity and low production cost, then environmental friendliness is improved, but low-temperature performance and electrical conductivity deteriorate
Solution Approach 1:
The patent changes the particle size parameter of lithium-rich manganese-based materials to a specific range (5-20 μm) and combines it with lithium iron phosphate in a controlled particle size distribution. This parameter optimization improves electrical conductivity and low-temperature performance while maintaining the low production cost advantage
3Quantity of substance
If olivine-type materials and lithium-rich manganese-based materials are used as positive electrode materials, then theoretical capacity is increased, but compaction density deteriorates, resulting in low volumetric energy density
Solution Approach 1:
The patent optimizes the particle size parameters of both lithium iron phosphate (0.5-5 μm) and lithium-rich manganese-based materials (5-20 μm) to achieve better packing efficiency. This parameter optimization increases compaction density from conventional levels to 2.4-2.6 g/cm³, thereby improving volumetric energy density while maintaining high theoretical capacity
Data Source
Figure 1~2
AI summary
The present invention provides a positive electrode active material composition and application thereof. The positive electrode active material composition includes at least the following ingredients: an ingredient A as a first active substance; an ingredient B as a second active substance; the particle size distributions of the first active substance and the second active substance satisfy: the ratio DAmin/DBmin of Dmin is 0.25 to 1.5, the ratio DA10/DB10 of Dio is 0.1 to 0.6, the ratio DA50/DB50 of D50 is 0.1 to 0.35, the ratio DA90/DB90 of D90 is 0.12 to 0.67, and 0.2≤[(DA90-DA10)/DA50]/[(DB90-DB10)/DB50]≤13. The invention provides a positive electrode active material composition and application thereof, which may effectively improve the volumetric energy density of lithium-ion secondary batteries.