LFMP Electrode Material Oil Absorption Optimization
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Solution Overview
Problem
Lithium iron manganese phosphate (LFMP) active materials in lithium ion batteries face challenges with cycle characteristics and high-rate input characteristics due to inadequate electrolyte solution retention properties, leading to limited Li ion migration and increased electrolyte decomposition at high voltages.
Innovation Solution
The electrode material for lithium ion batteries is optimized by setting specific ranges for diethyl carbonate oil absorption and the ratio of diethyl carbonate to N-methyl-2-pyrrolidinone, combined with a pyrolytic carbonaceous film coating, to enhance Li ion migration and reduce electrolyte decomposition, while maintaining suitable particle size and shape for improved conductivity and packing density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrolytic solution retention property around the active material is too strong, then the active material retains more electrolytic solutions, but the electrolytic solutions become deficient for the separator or anode, Li ion migration becomes slow, and battery reactions are limited
Solution Approach 1:
The patent applies parameter changes by optimizing the oil absorption amount of the electrode material (50-80 cc/100g) and the DEC/NMP ratio (1.3-1.8) to control electrolytic solution retention. This quantitative parameter optimization ensures balanced electrolyte distribution, preventing both excessive retention that would deprive other components and insufficient retention that would limit Li ion migration.
Solution Approach 2:
The patent applies local quality by creating different surface properties through pyrolytic carbonaceous film coating on the active material particles. This coating provides localized electrolyte retention at the particle surface while maintaining overall electrolyte availability in the battery, achieving spatially differentiated functionality.
2Quantity of substance
If the electrolytic solution retention property around the active material is too strong, then the active material retains more electrolytic solutions, but electrolytic solution decomposition amount significantly increases at high voltage
Solution Approach 1:
The patent uses parameter changes by optimizing the oil absorption amount (50-80 cc/100g) and DEC/NMP ratio (1.3-1.8) to achieve moderate electrolyte retention that prevents excessive decomposition at high voltage (4.1V or higher), balancing retention needs with decomposition suppression.
Solution Approach 2:
The pyrolytic carbonaceous film acts as an intermediary layer between the active material and electrolytic solution. This coating mediates the interaction by providing controlled retention while protecting the active material from direct contact that would cause decomposition, reducing both capacity loss and resistance increase.
3Area of moving object
If the particle size is miniaturized to increase the Li reaction area, then the battery reaction voltage increases, but the structural distortion increases
Solution Approach 1:
The patent applies flexible shells and thin films by coating the miniaturized active material particles with a pyrolytic carbonaceous film. This thin film coating provides mechanical support to maintain structural stability of small particles while preserving their high surface area for Li ion reactions, preventing structural distortion during charge-discharge cycles.
Solution Approach 2:
The patent uses composite materials by combining miniaturized active material particles with carbon coating and optimizing the electrolyte composition (DEC/NMP mixture). This composite structure maintains both the high reaction area of small particles and the structural stability provided by the carbon matrix and optimized electrolyte environment.
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 approach results in lithium ion batteries with enhanced cycle characteristics and input characteristics, improved Li ion migration, and reduced electrolyte decomposition, leading to higher capacity and efficiency in lithium ion batteries.
Implementation Method 1
a pyrolytic carbonaceous film coating
Implementation Method 2
suppress the electrolytic solution decomposition amount around LFMP active materials
Implementation Method 3
the oil absorption amount for which diethyl carbonate is used (DEC oil absorption amount) and the ratio (DEC/NMP) of the DEC oil absorption amount to an oil absorption amount for which N-methyl-2-pyrrolidinone is used (NMP oil absorption amount)
Data Source
AI summary
An electrode material for a lithium ion battery including an active material represented by LiMPO4 (Mis at least one selected from the group consisting of Fe, Mn, Co, Ni, Zn, Al, Ga, Mg, and Ca), in which an oil absorption amount for which diethyl carbonate is used (DEC oil absorption amount) is 50 cc/100 g or more and 80 cc/100 g or less, and a ratio (DEC/NMP) of the DEC oil absorption amount to an oil absorption amount for which N-methyl-2-pyrrolidinone is used (NMP oil absorption amount) is 1.3 or more and 1.8 or less.