Solid-State Battery Cathode Mixing for Low-Resistance Interfaces
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Solution Overview
Problem
All-solid-state batteries face challenges in forming a uniform interface between the positive electrode active material and solid electrolyte, leading to increased electric resistance and reduced ion conductivity, which affects the battery's lifespan and output.
Innovation Solution
A method of manufacturing a positive electrode for sulfide-based all-solid-state batteries involves mixing the positive electrode active material and solid electrolyte in a dry state, followed by adding a conducting agent in a dry state, and then incorporating a binder and solvent in a wet state, allowing for controlled addition of additional electrolyte and conducting agents to optimize the electrode structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid electrolyte is mixed with binder and solvent in slurry preparation, then the electrode can be formed by coating, but the interface between active material and solid electrolyte deteriorates and electric resistance increases
Solution Approach 1:
The patent divides the mixing process into two distinct stages: first mixing the solid electrolyte with the active material in a dry state to form a uniform mixture, then separately mixing the binder with solvent to form a binder solution. This segmentation prevents the binder and solvent from interfering with the solid electrolyte-active material interface while still enabling coating formation.
Solution Approach 2:
The patent performs preliminary mixing of the solid electrolyte with the active material before adding any binder or solvent. This preliminary action ensures that the solid electrolyte is uniformly distributed on the active material surface, establishing a good interface before the binder solution is introduced, thereby preventing interface deterioration.
2Quantity of substance
If solid electrolyte powder is pulverized into fine particles to increase surface area, then mixing is improved, but mechanical and chemical conductivity deteriorate
Solution Approach 1:
The patent optimizes the particle size parameters of the solid electrolyte, controlling it to be within a specific range (0.1-10 μm) rather than using excessively fine particles. This parameter control balances the surface area needed for mixing with the mechanical and chemical conductivity required for reliable electrode formation.
3Strength
If binder is added to improve electrode structure, then mechanical strength increases, but electric resistance increases due to interference with interface formation
Solution Approach 1:
The patent uses a binder solution (binder mixed with solvent) as an intermediary that is applied after the solid electrolyte-active material mixture is prepared. The solvent allows the binder to be uniformly distributed without directly interfering with the solid electrolyte-active material interface, thus maintaining both mechanical strength and interface quality.
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 reduces electric resistance and enhances ion conductivity, resulting in improved battery performance with increased ion conductivity and reduced surface resistance, thereby enhancing the battery's capacity and efficiency.
Implementation Method 1
a solid electrolyte 20 including lithium ions are commonly abut is formed, and this point is referred to as a triple point 40. Since the triple point is a point at which an electrochemical reaction occurs in an electrode, it is preferable to occur many electrochemical reactions by forming many triple points in the electrode.
Implementation Method 2
a mixture slurry with low fluidity was prepared by mixing fine solid particles with a solvent, and then coated on a metal current collector as a thin film, dried and compressed.
Data Source
AI summary
A method of manufacturing a positive electrode for sulfide-based all-solid-state batteries, including: preparing a slurry, coating the slurry on a current collector, and then drying. The slurry is prepared by a method including the steps of a) mixing a positive electrode active material and a solid electrolyte in a dry state; b) adding a conducting agent to the mixture of step a) and mixing in a dry state; and c) adding a binder and a solvent to the mixture of step b) and mixing in a wet state.