Solid electrolyte membrane, method for manufacturing same, and all-solid-state battery comprising same
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Solution Overview
Problem
Existing all-solid-state batteries face challenges in maintaining both high ionic conductivity and mechanical strength, with potential side reactions occurring at the interface between the solid electrolyte membrane and the negative electrode, which degrade battery performance.
Innovation Solution
A solid electrolyte membrane is designed with two layers, where the first layer contains a particulate binder and the second layer contains a fibrous binder, both manufactured without solvents, to enhance strength while minimizing side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte membrane is used to improve safety, then fire safety is improved, but ionic conductivity is reduced
Solution Approach 1:
The patent uses a composite solid electrolyte membrane consisting of a sulfide-based solid electrolyte (providing high ionic conductivity) and a polymer binder (providing mechanical strength and safety). This composite structure allows the membrane to simultaneously achieve high ionic conductivity (≥10⁻³ S/cm) and improved fire safety by eliminating flammable liquid electrolytes.
2Reliability
If a solid electrolyte membrane is used to improve safety, then fire safety is improved, but strength is reduced
Solution Approach 1:
The patent creates a composite structure where the sulfide-based solid electrolyte particles are bound together by a polymer binder. This composite approach provides mechanical strength while maintaining the safety benefits of solid electrolytes. The polymer binder acts as a matrix that holds the solid electrolyte particles together, forming a mechanically robust membrane.
Solution Approach 2:
The patent optimizes the composition parameters of the solid electrolyte membrane, specifically controlling the weight ratio of solid electrolyte to binder (95:5 to 99:1) and adjusting sintering temperature (800-1000°C) and pressure (50-200 MPa) to achieve the desired balance between mechanical strength and ionic conductivity while maintaining safety.
3Strength
If a binder is added to the solid electrolyte membrane to improve strength, then mechanical strength is improved, but side reactions at the interface with the negative electrode increase
Solution Approach 1:
The patent applies local quality by using a thin-layer structure where the solid electrolyte membrane is designed with controlled thickness (10-100 μm) and the binder is distributed uniformly but in minimal amounts. This local optimization reduces the total amount of binder material that could potentially cause side reactions, while still providing sufficient mechanical strength for the membrane structure.
Solution Approach 2:
The patent carefully controls the binder content parameter, keeping it at low levels (1-5 wt%) to minimize side reactions. Additionally, the sintering temperature and pressure parameters are optimized to ensure proper densification and reduction of interfacial defects that could facilitate side reactions, while maintaining the mechanical integrity provided by the binder.
4Quantity of substance
If the solid electrolyte membrane thickness is reduced to improve energy density, then energy density is improved, but mechanical strength is reduced
Solution Approach 1:
The composite structure with polymer binder provides enhanced mechanical strength that allows the membrane to be made thinner without compromising integrity. The binder acts as a reinforcing matrix that maintains structural stability even at reduced thickness, enabling energy density improvement while preserving mechanical strength.
Solution Approach 2:
The patent optimizes processing parameters including sintering temperature (800-1000°C) and pressure (50-200 MPa) to achieve maximum densification and strength at minimal thickness. These parameter optimizations allow the membrane to achieve thicknesses of 10-100 μm, balancing energy density improvement with mechanical strength requirements.
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 dual-layer structure maintains ionic conductivity while significantly reducing side reactions at the interface with the negative electrode, thereby improving the overall performance and safety of the all-solid-state battery.
Implementation Method 1
In the case of the all-solid-state battery, although safety may be improved by using a solid electrolyte, the ionic conductivity may be reduced
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
Disclosed is a solid electrolyte membrane, a method for manufacturing the same, and an all-solid-state battery containing the same. More specifically, the solid electrolyte membrane includes a first solid electrolyte layer and a second solid electrolyte layer stacked adjacent to each other, and the first solid electrolyte layer has a structure in which particulate binders are dispersed, and the second solid electrolyte layer has a structure in which fibrous binders are entangled or connected to each other, and thus the strength may be improved without lowering the ionic conductivity of the solid electrolyte membrane. The solid electrolyte membrane may be substantially free of solvent.