Nanosized Sulfide Solid-State Electrolyte for Higher Cathode Contact
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Solution Overview
Problem
Commercial lithium-ion batteries face limitations in energy density and safety due to large-sized sulfide electrolyte particles, which require high amounts of electrolyte to ensure contact with cathode materials, reducing the active material content and posing safety risks.
Innovation Solution
A nanosized sulfide solid-state electrolyte material is produced through a method involving solvents, dispersants, and mechanical dispersion to refine grain structure and reduce particle size to 10-500 nm, enhancing ion transport capacity and contact area with cathode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sulfide electrolyte particles are made large (5-10 μm), then the mechanical strength and handling stability are improved, but the specific surface area decreases, requiring more electrolyte powder (over 30% by mass) to ensure full contact with cathode material, which reduces active material content
Solution Approach 1:
The sulfide electrolyte particles are segmented into nanoscale sizes (10-500 nm), dramatically increasing the specific surface area. This segmentation allows much less electrolyte powder (reduced from over 30% to minimal content) to achieve sufficient contact area with cathode material, thereby increasing active material content while maintaining effective ion transport pathways
Solution Approach 2:
The particle size parameter is changed from micrometer scale (5-10 μm) to nanometer scale (10-500 nm). This parameter change fundamentally alters the surface area to volume ratio, enabling the electrolyte to provide adequate contact area with cathode material at much lower mass fractions, thus resolving the contradiction between mechanical strength and electrolyte content requirements
2Ease of manufacture
If sulfide electrolyte particles are made large (5-10 μm), then the manufacturing simplicity is maintained, but the contact area with cathode material decreases, reducing ion transport efficiency and battery performance
Solution Approach 1:
The electrolyte particles are segmented to nanoscale dimensions, providing extensive contact area with cathode material throughout the electrode structure. This segmentation ensures that ion transport pathways are established across the entire cathode surface, dramatically improving interfacial contact and ion transport efficiency while maintaining manufacturability through conventional processing techniques
Solution Approach 2:
The nanosized electrolyte particles create a porous-like network structure within the cathode composite, providing numerous pathways for ion transport. This structure maximizes the contact area between electrolyte and cathode material, enabling efficient ion conduction without requiring excessive electrolyte content, thus improving both contact area and manufacturing feasibility
3Reliability
If high proportion of electrolyte powder (over 30% by mass) is added to ensure contact, then the ion transmission is normalized, but the active material content in cathode is reduced, lowering energy density and battery performance
Solution Approach 1:
By segmenting the electrolyte into nanoscale particles (10-500 nm), the specific surface area is dramatically increased. This allows the electrolyte to form effective contact networks with cathode material at much lower mass fractions (reducing from over 30% to minimal content), thereby maintaining reliable ion transmission while preserving high active material content for superior energy density
Solution Approach 2:
The particle size parameter is reduced from micrometer to nanometer scale, fundamentally changing the surface area to volume ratio. This parameter change enables the electrolyte to provide sufficient contact area and ion transmission pathways at minimal mass content, resolving the contradiction between ensuring reliable ion transmission and maximizing active material content for high energy density
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 nanosized electrolyte increases the active material proportion in the cathode, improving battery performance by increasing ion transport capacity and stability, allowing for higher energy density and safer operation.
Implementation Method 1
mechanical dispersion is used to break the growing dendrites and increase the number of crystal nuclei, thereby refining the grain structure and reducing the particle size
Implementation Method 2
heat treating, pulverizing and grinding the electrolyte precursor powder obtained in step (2) to obtain the nanosized sulfide solid-state electrolyte material
Implementation Method 3
The nanosized sulfide solid-state electrolyte material can effectively increase the contact area with an active cathode material and the ion transport capacity
Data Source
AI summary
Provided is a preparation method of a nanosized sulfide solid-state electrolyte material. The preparation method includes the following steps: (1) preparing a Li2S material; (2) mixing 10-100 parts by weight of a solvent, 0-1 parts by weight of a dispersant, and 1 part by weight of a raw material containing the Li2S material in a closed container, and drying the mixture to obtain an electrolyte precursor powder; and (3) heat treating, pulverizing and grinding the electrolyte precursor powder obtained in step (2) to obtain the nanosized sulfide solid-state electrolyte material. The invention is simple in preparation process and the prepared electrolyte is nanosized.