Composite Electrolyte Membrane With Phase-Change Interface Layer
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Solution Overview
Problem
All-solid-state batteries face issues with dead spaces and high resistance at the interface between the electrode and the solid electrolyte membrane due to non-uniform electrode surfaces and dendrite growth, leading to reduced performance and safety concerns.
Innovation Solution
A composite electrolyte membrane with a phase change layer containing a porous sheet and a filler that transitions from a solid to a liquid state at elevated temperatures, filling dead spaces and improving ionic conductivity and reducing interfacial resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte membrane is used in an all-solid-state battery, then safety is improved and energy density is increased, but dead spaces and high resistance occur at the electrode-electrolyte interface
Solution Approach 1:
The patent applies local quality by creating a phase change layer with specific properties (porous structure filled with phase change material) only at the electrode-electrolyte interface where dead spaces occur. This localized modification fills gaps and improves contact only where needed, without changing the entire electrolyte membrane structure, thus resolving the interface uniformity problem while maintaining the overall safety benefits of the solid electrolyte membrane.
Solution Approach 2:
The patent utilizes parameter changes by incorporating a phase change material that transitions from solid to liquid at specific temperatures. This temperature-dependent phase change dynamically adjusts the interface properties: at operating temperatures, the material is liquid and fills dead spaces to improve contact and reduce resistance, while at lower temperatures it returns to solid state to maintain structural integrity.
2Productivity
If the electrode surface is non-uniform due to active material shape, coagulation, or swelling, then dead spaces increase and resistance increases, but the electrode structure provides necessary porosity for ion transport
Solution Approach 1:
The patent introduces a phase change layer as an intermediary between the electrode and solid electrolyte membrane. This intermediate layer contains a porous structure filled with phase change material that adapts to the non-uniform electrode surface, filling dead spaces and improving contact. The intermediary layer thus mediates between the rough electrode surface and the solid electrolyte, enabling good electrical contact while preserving the electrode's necessary porosity for ion transport.
3Quantity of substance
If lithium metal is used for the negative electrode, then capacity density is improved, but dendrite growth occurs during repeated charging/discharging
Solution Approach 1:
The patent applies beforehand cushioning by placing a phase change layer between the lithium metal negative electrode and the solid electrolyte membrane. This intermediate layer acts as a protective buffer that prevents direct contact between lithium metal and the electrolyte, thereby preventing dendrite growth during charging/discharging cycles. The phase change material absorbs mechanical stress and prevents lithium penetration, cushioning against the harmful effects of dendrite formation while allowing lithium ions to pass through.
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 phase change layer enhances ionic conductivity, reduces resistance, and improves battery life and safety by filling gaps and forming a solid electrolyte interphase film, preventing dendrite growth and mechanical degradation.
Implementation Method 1
a filler with which the pores of the porous sheet are filled, wherein the porous sheet includes polymer resin, and the filler exists in a solid state at 26°C or less and a liquid state at 35°C or above
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
A composite electrolyte membrane according to the present disclosure includes a phase change layer on a surface in contact with an electrode, for example, a positive electrode. The phase change layer includes a filler, and a physically isolated area between the positive electrode and the composite electrolyte membrane, known as a dead space, is filled with the filler that is liquefied by heat resulting from the increased internal temperature of the battery, thereby reducing the interfacial resistance between the electrolyte membrane and the electrode.