Solid-State Electrode Mixture for Low Resistance and High Energy Density
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Solution Overview
Problem
Existing batteries face challenges in achieving both low resistance and high volumetric energy density.
Innovation Solution
The electrode mixture comprises a layered rock salt type electrode active material, a sulfide solid electrolyte, and a conductive aid, with a D50 particle size of the electrode active material between 2.5 μm and 4.5 μm, and a conductive aid to sulfide solid electrolyte mass ratio between 2.0% and 11.0%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the particle size of electrode active material is reduced to increase volumetric energy density, then the volumetric energy density is improved, but the resistance increases due to poorer conductivity
Solution Approach 1:
The patent optimizes the D50 particle size parameter to a specific range (2.5-4.5 μm) to balance volumetric energy density and resistance. This parameter optimization resolves the contradiction by finding the optimal particle size that provides sufficient packing density while maintaining adequate conductivity through appropriate particle size for effective conductive network formation.
Solution Approach 2:
The patent creates a composite electrode mixture containing layered rock salt type electrode active material, sulfide solid electrolyte, and conductive aid. This composite structure resolves the contradiction by combining multiple materials with complementary properties: the active material provides energy density, the solid electrolyte enables ion conduction, and the conductive aid ensures electronic conductivity, achieving both low resistance and high volumetric energy density.
2Reliability
If the content of conductive aid is increased to reduce resistance, then the resistance is reduced, but the volumetric energy density decreases due to higher proportion of non-active material
Solution Approach 1:
The patent optimizes the mass ratio of conductive aid to sulfide solid electrolyte within a specific range (2.0-11.0%) to balance resistance and volumetric energy density. This parameter optimization resolves the contradiction by determining the minimum effective conductive aid content needed to establish adequate conductivity while maximizing the proportion of energy-storing active material.
Solution Approach 2:
The sulfide solid electrolyte acts as an intermediary between the electrode active material and conductive aid, facilitating both ion transport and electrical conduction. This intermediary role allows the system to achieve low resistance without requiring excessive conductive aid, thereby preserving volumetric energy density.
3Volume of moving object
If the particle size distribution is broadened to increase volumetric energy density, then the volumetric energy density is improved, but the resistance increases due to non-uniform conductive network
Solution Approach 1:
The patent specifies a narrow D50 particle size range (2.5-4.5 μm) with controlled distribution to achieve uniform particle packing. This parameter control resolves the contradiction by ensuring consistent particle sizes that pack efficiently to maximize volumetric energy density while maintaining uniform spacing for effective conductive network formation, preventing resistance increase.
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 results in a battery with low resistance and high volumetric energy density, as demonstrated by the examples where the D50 particle size and conductive aid ratio are optimized.
Implementation Method 1
a sulfide solid electrolyte
Implementation Method 2
a conductive aid
Data Source
AI summary
An electrode mixture that can achieve both a low resistance and a high volumetric energy density, and a solid-state battery including such an electrode mixture. The electrode mixture includes a layered rock salt type electrode active material, a sulfide solid electrolyte, and a conductive aid. A D50 particle size of the layered rock salt type electrode active material is 2.5 μm or more and 4.5 μm or less, and a ratio of a mass of the conductive aid to a mass of the sulfide solid electrolyte is 2.0% by mass or more and 11.0% by mass or less.