Solid-State Battery SEI Formation and Polymeric Film Interface

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Solution Overview

Problem

Existing lithium-ion batteries face challenges with safety hazards, flammability, and limitations in energy density, charging rate, and material costs, necessitating improved solid-state batteries with a solid electrolyte to enhance performance and safety.

Innovation Solution

The formation of solid-state batteries involves using a non-inert gas to displace ambient gases, forming a solid electrolyte interphase (SEI) and reducing interfacial resistance, while employing electrospraying to create a thin polymeric film that suppresses dendritic growth and maintains ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid electrolyte is used in lithium-ion batteries, then ionic conductivity is maintained, but safety hazards and flammability increase

Engineering Contradiction:
ImprovesafetyVSAvoidflammability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the parameter of electrolyte phase. This transformation eliminates flammability while maintaining ionic conductivity through the solid-state electrolyte material, directly resolving the safety-flammability contradiction

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transition by employing a solid-state electrolyte instead of liquid electrolyte. This phase change from liquid to solid state eliminates the harmful flammability characteristic while preserving the essential ionic conduction function, addressing the safety concerns of conventional batteries

Inventive Principle:
Principle #36Phase transitions

2Reliability

If a solid-state electrolyte is used, then safety and cycle life are improved, but interfacial resistance increases

Engineering Contradiction:
Improvecycle lifeVSAvoidinterfacial resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a polymeric film as an intermediary layer between the solid-state electrolyte and electrodes. This intermediary layer mediates the interface, reducing interfacial resistance and improving ion transport while allowing the solid-state electrolyte to maintain its safety and cycle life advantages

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure combining solid-state electrolyte with a polymeric film layer. This composite material approach integrates the safety benefits of solid-state electrolyte with the low interfacial resistance properties of the polymeric film, resolving the contradiction between cycle life and interfacial resistance

Inventive Principle:
Principle #40Composite materials

3Use of energy by moving object

If conventional battery materials are used, then manufacturing cost is reduced, but energy density and charging rate are limited

Engineering Contradiction:
Improveenergy densityVSAvoidmaterial cost
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent changes the electrolyte parameter from liquid to solid state, enabling the use of high-capacity electrode materials that were previously unsafe with liquid electrolytes. This parameter change allows achieving higher energy density while the electrospraying manufacturing process helps control production costs

Inventive Principle:
Principle #35Parameter changes

4Reliability

If dendritic growth is not suppressed, then manufacturing complexity is reduced, but battery safety and performance deteriorate

Engineering Contradiction:
Improvebattery safetyVSAvoidfilm structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a thin polymeric film as a flexible protective layer between electrodes. This thin film structure effectively suppresses dendritic growth and prevents internal shorts, enhancing battery safety without significantly increasing manufacturing complexity due to the simplicity of the film deposition process

Inventive Principle:
Principle #30Flexible shells and thin films

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 method results in improved interfacial ionic conductivities, higher energy density, longer cycle life, enhanced safety, and faster charging capabilities, reducing the risk of fires and maintaining performance across various temperatures.

Implementation Method 1

forming a solid electrolyte interphase (SEI) and reducing interfacial resistance

Methodology Applied
Scientific EffectSolid electrolyte interphase (SEI) formation:

Implementation Method 2

employing electrospraying to create a thin polymeric film

Methodology Applied
Scientific EffectElectrospraying: Electrohydrodynamics

Implementation Method 3

a solid-state electrolyte that advantageously provides low interfacial resistance

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4233117B1Solid-state battery and method of forming same
Publication Date: 2026.01.07 WATTRII INC
  • EP4233117B1 patent drawingFigure 1
  • EP4233117B1 patent drawingFigure 2
  • EP4233117B1 patent drawingFigure 3

AI summary

Methods of forming an electrochemical cell using a non-inert gas are disclosed. Exemplary methods include providing a first gas before applying or more of current and voltage to the cell. The first (e.g., non-inert) gas can facilitate formation of a solid electrolyte interphase (SEI). Further examples of the disclosure relate to methods of forming an electrochemical cell or portion thereof by electro spraying a solution including polymeric material. Such methods potentially eliminate a step of compressing the cell at a pressure beyond 100 MPa and prolong the cycle life while preventing a fire hazard.