Solid-State Li-Ion Anode Layer Structure to Suppress Dendrites

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Solution Overview

Problem

Existing all-solid-state lithium-ion secondary batteries require high external pressure to prevent the formation of dendrites and voids, which hinders battery thinning and reduces discharge capacity and lifetime.

Innovation Solution

An all-solid-state lithium-ion secondary battery design featuring a negative electrode with a carbon material and Ag-based negative electrode active material layer composed of two or more sub-layers, with varying Ag contents, to eliminate the need for high external pressure and enhance discharge capacity and lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high external pressure is applied to prevent dendrite formation and void creation, then battery reliability is improved, but battery thickness increases and discharge capacity decreases

Engineering Contradiction:

Improvebattery reliabilityVSAvoidbattery thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

An amorphous carbon interface layer is introduced as an intermediary between the metal lithium negative electrode active material and the solid electrolyte. This intermediate layer prevents direct contact and interaction that would lead to dendrite formation and void creation, thereby maintaining battery reliability without requiring high external pressure, thus avoiding increased battery thickness

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode active material is changed from conventional materials to metal lithium with specific parameters (purity ≥99.9%, particle size 0.1-10 μm). This parameter change enables lithium to function as the active material while the amorphous carbon interface layer prevents harmful side effects, achieving both high capacity and reliability without thickening the battery

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If high external pressure is applied to prevent dendrite formation, then battery lifetime is improved, but discharge capacity decreases

Engineering Contradiction:

Improvebattery lifetimeVSAvoiddischarge capacity

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The amorphous carbon interface layer serves as a mediator that prevents direct interaction between lithium and the solid electrolyte, eliminating the need for high external pressure to prevent dendrites and voids. This enables the battery to maintain high discharge capacity while achieving long cycle life through improved interface stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode is designed as a composite structure combining metal lithium particles (≥99.9% purity, 0.1-10 μm size) with an amorphous carbon interface layer. This composite material approach leverages the high capacity of lithium while the carbon layer provides structural stability and prevents degradation, achieving both high discharge capacity and extended battery lifetime without requiring high external pressure

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If metal lithium is used as negative electrode active material to increase capacity density, then energy density is improved, but dendrite formation occurs requiring external pressure

Engineering Contradiction:

Improvecapacity densityVSAvoiddendrite formation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The amorphous carbon interface layer acts as a protective intermediary between metal lithium and the solid electrolyte, preventing the formation of dendrites and voids that normally occur with lithium. This enables the use of high-capacity-density lithium without the harmful side effects, maintaining both high energy density and structural integrity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Metal lithium is used as the negative electrode active material with controlled parameters (purity ≥99.9%, particle size 0.1-10 μm), representing a significant parameter change from conventional materials. This parameter change achieves 10 times the capacity density of graphite while the amorphous carbon interface layer prevents dendrite formation, eliminating the need for high external pressure

Inventive Principle:

Principle #35Parameter changes

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 battery design suppresses dendrite formation and maintains excellent discharging capacity and lifetime characteristics without requiring external pressure.

Implementation Method 1

a solid electrolyte interposed between the positive electrode and the negative electrode

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

the negative electrode active material layer comprises a carbon material and Ag

Methodology Applied

Scientific EffectAlloying: Solid Solution Strengthening

Data Source

PatentUS20250253312A1All-Solid-State Lithium-Ion Secondary Battery

Publication Date: 2025.08.07 LG ENERGY SOLUTION LTD

AI summary

An all-solid-state lithium-ion secondary battery includes a positive electrode, a negative electrode, and a solid electrolyte between the positive electrode and the negative electrode. The negative electrode has a negative electrode current collector and a negative electrode active material layer that comprises a carbon material and Ag.