Dual-Layer Solid Electrolyte Sheet for Lithium Dendrite Suppression

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Solution Overview

Problem

Existing all-solid-state batteries face reliability issues due to the risk of short circuits caused by lithium dendrite deposition during charging, which limits their capacity and safety.

Innovation Solution

A solid electrolyte sheet with a porous substrate and dual-layer structure, comprising a reactive solid electrolyte layer that oxidizes lithium and a less reactive layer to inhibit dendrite growth, is used in the battery design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a solid electrolyte sheet with a porous substrate is used to increase battery size and capacity, then higher capacity is achieved, but lithium dendrite deposition causes short circuits and reduces reliability

Engineering Contradiction:
Improvebattery capacityVSAvoidshort circuit prevention
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The solid electrolyte sheet is divided into multiple layers with different functions: a first solid electrolyte layer containing reactive solid electrolyte particles for suppressing dendrite growth, and a second solid electrolyte layer containing less reactive solid electrolyte particles for maintaining lithium ion conductivity. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between capacity and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the solid electrolyte sheet have different material compositions and properties. The first layer near the negative electrode has high reactivity with lithium for dendrite suppression, while the second layer has lower reactivity for optimal ion transport. This local differentiation of material properties enables simultaneous achievement of high capacity and high reliability.

Inventive Principle:
Principle #3Local quality

2Reliability

If a reactive solid electrolyte is used to suppress lithium dendrite growth, then reliability is improved, but lithium-ion conductivity may be reduced

Engineering Contradiction:
Improvedendrite growth suppressionVSAvoidlithium-ion conductivity
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The solid electrolyte sheet is divided into two functional layers: the first layer uses highly reactive solid electrolyte particles to suppress dendrite growth, while the second layer uses less reactive particles to ensure high lithium-ion conductivity. This segmentation allows each layer to optimize for its primary function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses composite material structures where different solid electrolyte materials are combined in specific layers. The first layer combines reactive solid electrolyte particles for dendrite suppression, while the second layer combines less reactive particles for optimal ion transport. This composite approach enables simultaneous achievement of both reliability and conductivity.

Inventive Principle:
Principle #40Composite materials

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 effectively suppresses lithium dendrite growth, enhancing battery reliability and preventing short circuits while maintaining favorable lithium-ion conductivity.

Implementation Method 1

a solid electrolyte layer A containing a solid electrolyte a that reacts with metallic lithium to oxidize lithium

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a solid electrolyte layer B containing a solid electrolyte b that is less reactive with metallic lithium than the solid electrolyte a

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP4715929A1Solid electrolyte sheet and all-solid-state battery
Publication Date: 2026.03.25 MAXELL LTD
  • EP4715929A1 patent drawingFigure 1~2
  • EP4715929A1 patent drawingFigure 3~4
  • EP4715929A1 patent drawing

AI summary

Provided are a highly reliable all-solid-state battery and a solid electrolyte sheet that can form a part of the all-solid-state battery. A solid electrolyte sheet according to the present invention has a porous substrate, and a solid electrolyte retained on the porous substrate, and the solid electrolyte sheet includes: a solid electrolyte layer A containing a solid electrolyte a that reacts with metallic lithium to oxidize lithium; and a solid electrolyte layer B containing a solid electrolyte b that is less reactive with metallic lithium than the solid electrolyte a, and the solid electrolyte layer B is disposed on at least one surface of the solid electrolyte sheet. An all-solid-state battery according to the present invention includes: a positive electrode; a negative electrode; and a solid electrolyte layer, and the solid electrolyte layer is the solid electrolyte sheet according to the present invention, and the solid electrolyte layer B of the solid electrolyte sheet faces the negative electrode.