Solid Electrolyte Layer Transfer for Durable All-Solid-State Batteries
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Solution Overview
Problem
All-solid-state batteries face issues with interfacial resistance and durability due to the thickness and mechanical properties of the solid electrolyte layer, which affects lithium ion conductivity and energy density, and existing transfer methods either harden the surface or result in non-uniform contact, leading to reduced capacity and efficiency.
Innovation Solution
A method involving the transfer of two solid electrolyte layers with different thicknesses onto the cathode and anode parts, using polyethylene naphthalate and fluorinated polyimide transfer films, and applying specific pressures and temperatures to form a uniform interface, reducing interfacial resistance and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the solid electrolyte layer is made thinner to increase energy density, then the energy density is improved, but the mechanical properties (strength, stiffness, flexibility) deteriorate
Solution Approach 1:
The solid electrolyte layer is divided into multiple thin layers (first solid electrolyte layer, second solid electrolyte layer, third solid electrolyte layer) instead of using a single thick layer. Each layer has a thickness of 1-10 μm, which maintains mechanical integrity while achieving the desired thin profile for high energy density. The segmented structure allows each thin layer to contribute to overall strength through collective support.
Solution Approach 2:
The patent uses composite solid electrolyte layers formed by stacking multiple layers with different compositions or structures. The composite structure combines the advantages of each individual layer, achieving both thinness for high energy density and sufficient mechanical strength through the synergistic effect of multiple layers working together.
2Strength
If the solid electrolyte layer is made thicker to improve mechanical properties, then the strength is improved, but the energy density deteriorates
Solution Approach 1:
Instead of using one thick solid electrolyte layer, the patent segments it into multiple thin layers (1-10 μm each). This segmentation achieves the desired mechanical properties through the cumulative effect of multiple layers while maintaining thin overall thickness to preserve high energy density.
3Reliability
If the compressibility is increased during transfer process to improve contact, then the interfacial contact is improved, but the surface hardening occurs and interfacial resistance increases
Solution Approach 1:
The patent applies a preliminary pressing treatment at a first pressing force to ensure good initial contact between the solid electrolyte layer and the electrode layer before the main transfer process. This preliminary action prepares the interface for optimal contact during subsequent steps while avoiding excessive compression that would cause surface hardening.
Solution Approach 2:
The pressing force is dynamically adjusted during the transfer process. The patent uses a first pressing force during initial contact formation, then adjusts to a second pressing force for the main transfer. This dynamic adjustment ensures proper interfacial contact without applying excessive force that would harden the surface and increase interfacial resistance.
4Object-affected harmful factors
If the compressibility is decreased during transfer process to prevent surface hardening, then the surface hardness is maintained, but the interfacial contact becomes insufficient and voids occur
Solution Approach 1:
A preliminary pressing step is performed at a controlled first pressing force to ensure adequate initial contact between layers. This preliminary action creates sufficient interfacial contact without applying excessive force that would cause surface hardening, preventing void formation while maintaining surface properties.
Solution Approach 2:
The pressing force is dynamically controlled with a first pressing force for initial contact and a second pressing force for main transfer. This dynamic adjustment ensures proper contact is achieved without excessive compression, maintaining surface hardness while preventing voids through optimized force application timing.
5Length of stationary object
If the binder content is increased to reduce solid electrolyte layer thickness, then the thickness is reduced, but the lithium ion conductivity deteriorates
Solution Approach 1:
The solid electrolyte layer is segmented into multiple thin layers (1-10 μm each) rather than using a single thick layer with high binder content. This segmentation achieves the desired thin profile while maintaining lithium ion conductivity through the continuous solid electrolyte phase in each layer, avoiding the need for excessive binder that would block ion transport.
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 approach results in improved charge/discharge capacity and durability of the all-solid-state battery by minimizing interfacial resistance and ensuring proper contact between the electrolyte layers, leading to higher initial discharge capacity and longer cycle life.
Implementation Method 1
The solid electrolyte layer may be thinly coated on a transfer film, and may be transferred onto the electrode layer by a method using a roll press, a flat press or the like. When such a transfer process is applied, it is easy to form a thin solid electrolyte layer. Further, the solid electrolyte layer is densely formed through a process of applying heat and pressure.
Implementation Method 2
An all-solid-battery includes a cathode layer, an anode layer, and a solid electrolyte layer interposed between the cathode layer and the anode layer.
Data Source
AI summary
Disclosed are an all-solid-state battery having high capacity and excellent durability and a method for manufacturing the same. The method includes preparing a first solid electrolyte part including a first transfer film layer and a first layer disposed on the first transfer film layer and including a first solid electrolyte, preparing a second solid electrolyte part including a second transfer film layer and a second layer disposed on the second transfer film layer and including a second solid electrolyte, forming a first solid electrolyte layer on a cathode part by transferring the first layer onto the cathode part, forming a second solid electrolyte layer on an anode part by transferring the second layer onto the anode part, and preparing a stack by stacking the first solid electrolyte layer and the second solid electrolyte layer so as to come into contact with each other.