Electrode with Ferroelectric Particles for Battery Energy Density
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in achieving high energy density while maintaining good input/output characteristics due to increased resistance from thickened electrode layers, which worsens with lithium ion diffusion distance.
Innovation Solution
The electrode incorporates a high ratio of ferroelectric particles in contact with active material particles and solid electrolyte particles with Li ion conductivity, optimizing their distribution to alleviate charge bias and maintain a sufficient diffusion path for lithium ions, even at increased layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode layer is thickened to enhance energy density, then the energy density increases, but the diffusion distance of lithium ions increases causing resistance to increase and input/output characteristics to deteriorate
Solution Approach 1:
The patent applies local quality by creating a dual-structure electrode where the surface layer contains high proportions of ferroelectric particles (8-20 mass%) and solid electrolyte particles (3-10 mass%) to reduce diffusion resistance at the interface, while the inner layer maintains higher active material content (90-95 mass%) for energy storage. This gradient composition optimizes both energy density and input/output characteristics by addressing the specific needs of different electrode regions.
Solution Approach 2:
The patent employs composite materials by combining active material particles with ferroelectric particles and solid electrolyte particles in specific ratios. The ferroelectric particles (such as barium titanate) provide polarized surfaces that facilitate lithium ion insertion/extraction, while solid electrolyte particles (such as LATP or LLZO) create conductive pathways. This composite structure reduces overall electrode resistance while maintaining high energy density through optimized thickness.
2Reliability
If the ratio of ferroelectric particles in contact with active material particles is increased to reduce charge bias, then input/output characteristics improve, but the complexity of particle distribution control increases
Solution Approach 1:
The patent applies preliminary action by pre-coating active material particles with ferroelectric particles before forming the electrode layer. This pre-arrangement ensures that when the electrode is assembled, the ferroelectric particles are already in optimal contact with active material particles, facilitating lithium ion diffusion and reducing charge bias without requiring complex post-assembly adjustments. The solid electrolyte particles are similarly pre-distributed to ensure adequate diffusion paths.
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 configuration enhances both input/output characteristics and energy density by reducing charge bias and diffusion resistance, allowing for improved performance in lithium ion secondary batteries.
Implementation Method 1
an active material-containing layer containing active material particles, ferroelectric particles, and solid electrolyte particles
Implementation Method 2
solid electrolyte particles having a Li ion conductivity of 1 × 10 -10
Data Source
Figure 1
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AI summary
According to one approach, an electrode is provided. The electrode includes an active material-containing layer containing active material particles (11), ferroelectric particles (13), and solid electrolyte particles (12). A ratio (FEcontact) of the number of the ferroelectric particles (13) in contact with the active material particles (11) relative to the number of the ferroelectric particles (13) included in the active material-containing layer is 85% or more. A ratio (SEnon-contact) of the number of the solid electrolyte particles (12) not in contact with the active material particles (11) relative to the number of the solid electrolyte particles (12) included in the active material-containing layer is 30% or more.