Dual-Polymer Electrolyte Layout for Lithium Metal Battery Stability

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Solution Overview

Problem

Lithium metal batteries suffer from side reactions at high-voltage cathodes and the growth of lithium dendrites, leading to deterioration and short circuits, which degrade the battery's performance and lifespan.

Innovation Solution

The battery incorporates a novel electrolyte structure with a catholyte and anolyte, each composed of a polymer electrolyte derived from single-ion conducting monomers and crosslinking monomers with reactive functional groups, preventing side reactions and suppressing dendrite growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal is used as anode active material to increase theoretical electrical capacitance, then energy density is improved, but side reactions with electrolyte occur causing deterioration of lifespan characteristics

Engineering Contradiction:
Improvetheoretical electrical capacitanceVSAvoidlifespan characteristics
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

A solid electrolyte interphase (SEI) layer is formed on the lithium metal anode surface through electrolyte decomposition. This SEI layer acts as an intermediary barrier that prevents direct contact between the lithium metal and the electrolyte, thereby suppressing side reactions while allowing lithium ion transport. This resolves the contradiction by enabling high capacitance lithium metal to function reliably without direct electrolyte contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrolyte composition and operating conditions to control the formation and properties of the SEI layer. By adjusting electrolyte additives, concentration, and potential window, the SEI layer's stability and protective properties are enhanced, preventing deterioration while maintaining high capacity utilization of the lithium metal anode.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If high-voltage cathode operating at 3.5 V or more is used to increase energy density, then electrical capacitance is improved, but organic solvent in electrolyte is oxidized causing side reactions and deterioration

Engineering Contradiction:
Improveelectrical capacitanceVSAvoidside reactions
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

A protective coating layer is applied to the high-voltage cathode surface, serving as an intermediary barrier between the cathode and the organic solvent electrolyte. This coating prevents direct oxidation reactions while allowing electron and ion transport, enabling the high-voltage cathode to operate without generating harmful side reactions that would deteriorate battery performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs electrolyte additives and composition modifications to raise the oxidation stability of the electrolyte. By changing the chemical parameters of the electrolyte (additives, concentration, pH), the oxidation potential is increased to match or exceed the cathode operating voltage, preventing solvent oxidation and side reactions while maintaining high capacitance.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If lithium-containing metal layer is repeatedly plated and dissolved during charging and discharging, then battery capacity is improved, but impurities accumulate making the surface rough and hard

Engineering Contradiction:
Improvebattery capacityVSAvoidsurface morphology
Core Design Contradiction:
Duration of action of moving objectVSStability of the object's composition

Solution Approach 1:

The lithium-containing metal layer is designed to self-heal and self-regulate during cycling. Through controlled plating and dissolution processes, the layer automatically removes impurities and maintains a smooth surface morphology. The system uses its own operational cycles to restore surface quality, enabling long-term capacity retention without external intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent optimizes cycling parameters such as current density, voltage window, and temperature to control the plating and dissolution processes. By adjusting these parameters, the formation and removal of impurities are minimized, and the surface morphology is maintained smooth and stable throughout extended cycling, preserving battery capacity over time.

Inventive Principle:
Principle #35Parameter changes

4Speed

If lithium dendrites grow continuously during charge and discharge process, then lithium ion transport is improved, but short circuit between anode and cathode occurs causing deterioration

Engineering Contradiction:
Improvelithium ion transportVSAvoidshort circuit prevention
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

A flexible protective film or coating is applied to the lithium metal anode surface. This thin film layer allows lithium ions to pass through while providing mechanical constraints that prevent dendrite protrusions from growing continuously. The film flexes with volume changes during cycling while maintaining its barrier function, enabling fast ion transport without short circuits.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent controls the electrochemical parameters (current density, voltage cutoff, temperature) to suppress dendrite formation kinetics. By optimizing these parameters, lithium deposition occurs uniformly rather than forming dendritic structures, maintaining high ion transport speed while preventing short circuits between electrodes.

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

This design enhances the stability of the electrolyte, reduces internal resistance, and improves the cycle characteristics of the lithium metal battery by preventing deterioration and suppressing dendrite formation.

Implementation Method 1

the first polymer electrolyte includes a first polymer, and the first polymer includes a first repeating unit derived from a first single ion conducting monomer

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

a second repeating unit derived from a first crosslinking monomer having a plurality of reactive functional groups

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentEP4579846A1Lithium metal battery and method for manufacturing lithium metal battery
Publication Date: 2025.07.02 SAMSUNG SDI CO LTD
  • EP4579846A1 patent drawingFigure 1
  • EP4579846A1 patent drawingFigure 2A
  • EP4579846A1 patent drawingFigure 2B

AI summary

Disclosed are a lithium metal battery and a manufacturing method therefor, the lithium metal battery including a cathode, an anode, and an electrolyte disposed between the cathode and the anode, wherein the anode includes a lithium metal, the electrolyte includes a catholyte disposed adjacent to the cathode and an anolyte disposed between the catholyte and the anode, the catholyte includes a first polymer electrolyte, the first polymer electrolyte includes a first polymer, and the first polymer includes a first repeating unit derived from a first single-ion conducting monomer and a second repeating unit derived from a first crosslinking monomer having a plurality of reactive functional groups.