Aqueous Cathode Slurry Stabilization for High-Voltage Li-Ion Batteries
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Solution Overview
Problem
Existing lithium-ion battery production methods face challenges in achieving high-performance cathodes for xEVs, particularly in maintaining particle size distribution and preventing agglomeration, which affects battery performance, especially at higher voltages, and are costly due to the use of solvents like NMP.
Innovation Solution
A method involving a slurry formulation with a lithium-nickel-manganese-cobalt composite oxide, using a water-alcohol mixture or an arene-capped polyoxoethylene surfactant to stabilize particle sizes below 15 microns, preventing agglomeration, and eliminating costly solvents like NMP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional solvents like NMP are used in slurry preparation, then particle dispersion is improved, but production cost increases due to solvent recycling requirements
Solution Approach 1:
The patent replaces expensive, recyclable solvents like NMP with water, which is inexpensive and does not require recycling. The slurry uses water as the liquid medium to disperse particles, eliminating solvent recovery infrastructure and reducing manufacturing costs while maintaining adequate particle dispersion for electrode formation
Solution Approach 2:
The patent changes the liquid medium parameter from organic solvents (NMP) to aqueous-based solutions (water with optional alcohol or surfactant). This parameter change maintains particle dispersion capability while eliminating the need for expensive solvent recycling processes, directly addressing the cost-performance trade-off
2Power
If high voltage is used in battery cells, then energy density is improved, but particle agglomeration increases affecting performance
Solution Approach 1:
The patent introduces an intermediary substance (alcohol or surfactant) into the aqueous slurry to mediate particle interactions. This intermediary prevents direct agglomeration of high-voltage cathode particles during slurry preparation and coating, maintaining stable particle size distribution even when processing materials designed for high voltage operation
Solution Approach 2:
The patent applies preliminary anti-agglomeration measures during slurry preparation by including alcohol or surfactant in the liquid medium. This preliminary protection prevents particle agglomeration before it occurs during high-voltage electrode operation, preserving particle size distribution and performance characteristics
3Reliability
If particle size is reduced to prevent agglomeration, then battery performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent enables the slurry system to self-regulate particle dispersion through the inherent properties of the aqueous-based liquid medium with alcohol or surfactant. The liquid naturally prevents agglomeration during mixing and coating processes, reducing the need for stringent external control measures while maintaining small, performance-optimizing particle sizes
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 approach results in enhanced battery performance, including capacity retention at high discharge rates and reduced production costs by preventing particle agglomeration and eliminating the need for solvent recycling.
Implementation Method 1
the slurry comprises particles dispersed within the liquid
Implementation Method 2
an arene-capped polyoxoethylene surfactant to stabilize particle sizes below 15 microns, preventing agglomeration
Implementation Method 3
drying the coating on the collector to form the positive electrode
Data Source
Figure 1~2
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Figure 5~6
AI summary
In one embodiment, a positive electrode is formed by a process that includes forming 102, 112 a slurry including particles dispersed within a liquid from a electrode formulation and the liquid such that the particles have a particle size distribution D50 of 15 microns or less, coating 104 the slurry on a collector, and drying 106 the coated collector to form the positive electrode. The electrode formulation includes an electrode active material, a conductive carbon source, an organic polymeric binder, and a water-soluble polymer. The liquid consists essentially of water or a mixture of water and an alcohol. When the liquid consists essentially of the mixture, the alcohol is present in an amount of less than 10% by weight, based on the weight of the slurry. When the liquid consists essentially of water, the slurry is formed from the electrode formulation, the liquid, and an arene-capped polyoxoethylene surfactant.