Low Porosity Solid Electrolyte Membrane via Wet-Coating

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Solution Overview

Problem

Conventional all-solid-state batteries face issues with lithium dendrite formation leading to short circuits and require high-temperature, costly manufacturing processes, which compromise mechanical strength and porosity of the solid electrolyte membrane.

Innovation Solution

A solid electrolyte membrane is produced by wet-coating sulfide or oxide particles with a thermoplastic resin or a mixture of thermoplastic and thermosetting resins, followed by hot-pressing at low temperatures and pressures, controlling porosity and inhibiting lithium dendrite formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional production methods are used to manufacture solid electrolyte membranes, then manufacturing cost and process complexity are reduced, but porosity increases leading to lithium dendrite formation and short circuits

Engineering Contradiction:

Improveinhibition of lithium dendrite formationVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The solid electrolyte particles are pre-coated with binder material and organic additive before hot-pressing. This preliminary coating action ensures uniform distribution of functional materials on particle surfaces, which controls pore formation and prevents lithium dendrite growth during subsequent battery operation, thereby improving reliability without significantly complicating the manufacturing process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the hot-pressing parameters (temperature, pressure, time) to optimize the sintering process. By controlling these parameters, the method achieves low porosity and dense structure that prevent lithium dendrite formation, while maintaining manufacturability through standardized processing conditions

Inventive Principle:

Principle #35Parameter changes

2Strength

If high-temperature hot-pressing is used to reduce porosity, then mechanical strength and electrochemical stability are improved, but manufacturing cost and process difficulty increase

Engineering Contradiction:

Improvemechanical strength of solid electrolyte membraneVSAvoidhot-pressing temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

Organic additive materials serve as intermediaries during the hot-pressing process. These additives facilitate sintering at lower temperatures by promoting particle bonding and pore closure, thereby achieving high mechanical strength and low porosity without requiring excessive heating, thus reducing manufacturing cost and process difficulty

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solid electrolyte membrane is formed as a composite structure containing solid electrolyte particles, binder material, and organic additive. This composite composition enables the achievement of high mechanical strength and electrochemical stability through synergistic effects of the components, while allowing processing at moderate temperatures that reduce manufacturing complexity

Inventive Principle:

Principle #40Composite materials

3Reliability

If high porosity is maintained in the solid electrolyte membrane, then ionic conductivity is improved, but mechanical strength decreases and lithium dendrites can penetrate causing short circuits

Engineering Contradiction:

Improveelectrochemical stabilityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention creates local quality differences within the membrane structure by forming a dense outer layer that prevents lithium dendrite penetration while maintaining appropriate porosity in the bulk for ionic conductivity. The binder material and organic additive are strategically distributed to reinforce mechanical strength at critical locations without compromising overall electrochemical performance

Inventive Principle:

Principle #3Local quality

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 approach enhances mechanical strength, reduces porosity, and improves electrochemical stability, preventing short circuits and extending cell cycle life while enabling high-energy density batteries at lower manufacturing costs.

Implementation Method 1

hot-pressing the composite at a relatively low temperature and at a low pressure

Methodology Applied

Scientific EffectPhase transition: Phase Change

Implementation Method 2

removing the solvent by drying to prepare a solid electrolyte composite

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11335951B2Low porosity solid electrolyte membrane and method for manufacturing the same

Publication Date: 2022.05.17 HYUNDAI MOTOR CO LTD

AI summary

An improved, low porosity, solid electrolyte membrane and a method of manufacturing the solid electrolyte membrane are provided. The low porosity, solid electrolyte membrane significantly improves both mechanical strength and porosity of the membrane, inhibits the growth of lithium dendrites (Li dendrites), and thereby maintains and maximizes electrochemical stability of an all-solid-state battery. This is accomplished by wet-coating a sulfide or oxide solid electrolyte particle with a thermoplastic resin, or a mixture of the thermoplastic resin and a thermosetting resin, using a solvent to prepare a composite and hot-pressing the composite at a relatively low temperature and at a low pressure.