Solid-State Battery Electrode Coating for Particle Dispersion Stability
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Solution Overview
Problem
All-solid state batteries experience increased resistance over long-term use due to the aggregation of active material particles, which disrupts ion conduction paths, leading to potential breaks and accelerated resistance growth.
Innovation Solution
Incorporating imidazoline-based compounds as dispersing agents in the electrode composition, specifically within the fluoride solid electrolyte coating layer, to enhance dispersibility and reduce aggregation of active material particles, thereby minimizing resistance increase rates. The optimal blending amount of the imidazoline-based compound is between 0.05 to 0.1 parts by mass, and the fluoride solid electrolyte is represented by Formula (2), with a specific surface area ratio of the composite particle to the core particle between 1.07 and 3.27.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active material particles are used in the electrode, then the battery can function with ion conduction, but the particles aggregate during long-term use causing resistance increase
Solution Approach 1:
A coating layer comprising a fluoride solid electrolyte is formed on the surface of active material particles. This coating layer acts as an intermediary that prevents direct contact and aggregation between active material particles while maintaining ion conduction pathways, thereby suppressing resistance increase during long-term use.
2Stability of the object's composition
If dispersing agents are added to improve particle dispersion, then aggregation is reduced, but excessive dispersing agent increases resistance due to insulating properties
Solution Approach 1:
Instead of using organic dispersing agents, the patent changes the approach by forming an inorganic fluoride solid electrolyte coating layer on particle surfaces. This coating provides dispersibility through physical separation while maintaining ion conductivity, eliminating the trade-off between dispersion and resistance that plagues organic dispersing agents.
3Stability of the object's composition
If fluoride solid electrolyte coating is applied to active material particles, then particle aggregation is suppressed and dispersibility is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The coating formation process is integrated with the electrode manufacturing process itself. The fluoride solid electrolyte coating is formed on active material particles during the slurry preparation and coating stages, combining the coating step with existing manufacturing operations rather than requiring separate post-processing steps.
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 use of imidazoline-based compounds effectively reduces the resistance increase rate by maintaining high dispersibility and ion conductivity, preventing particle aggregation and maintaining low reaction resistance, even after long-term use.
Implementation Method 1
the IM compound can act as a dispersing agent for SE. According to the novel findings of the present disclosure, the IM compound can impart high dispersibility, in particular, to the fluoride SE
Implementation Method 2
there is a possibility that a surrounding ion conduction path cannot respond to a large volume change of the aggregate, which results in a break in the ion conduction path
Data Source
AI summary
An electrode for an all-solid state battery contains composite particles of 100 parts by mass and an imidazoline-based compound of more than 0 parts by mass and 0.3 parts by mass or less. The composite particle includes a core particle and a coating layer. The coating layer covers at least a part of a surface of the core particle. The core particle contains an active material. The coating layer contains a fluoride solid electrolyte.