Composite Separator Electrolyte for Stable Solid-State Battery Interfaces

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Solution Overview

Problem

Solid state batteries face challenges in achieving sufficient conductivity, compatibility with electrodes, and mechanical stability due to the need for a solid electrolyte that meets these criteria.

Innovation Solution

A composite separator and electrolyte system is developed, comprising a porous self-supporting separator film coated with electrolyte films containing lithium salts, glymes, and polymeric complexing agents, which separates mechanical and ionic conduction functions, ensuring compatibility and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a solid electrolyte is used in solid state batteries, then packaging requirements are reduced, but compatibility with electrodes and mechanical properties are insufficient

Engineering Contradiction:

Improvepackaging complexityVSAvoidelectrode compatibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs a porous self-supporting separator film as the base structure. The porous structure provides mechanical integrity while allowing electrolyte penetration and electrode contact, improving compatibility with electrodes. The porosity enables the separator to maintain structural stability without requiring complex packaging while facilitating ionic transport and electrode interface compatibility.

Inventive Principle:

Principle #31Porous materials

2Reliability

If electrolyte films are applied to both sides of the porous separator, then ionic conductivity is enhanced, but the device complexity increases

Engineering Contradiction:

Improveionic conductivityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the separator function and electrolyte function into a single integrated composite structure. The electrolyte films are applied directly to both sides of the porous separator, merging the mechanical separation function with the ionic conduction function. This integration enhances ionic conductivity while avoiding the need for separate electrolyte components, thus not significantly increasing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 composite separator and electrolyte system enhances ionic conductivity, mechanical stability, and compatibility with electrodes, leading to improved performance and extended battery life in solid state batteries.

Implementation Method 1

a polymeric complexing agent present in an amount of from 5 to 80 percent by weight, based on the total weight of the electrolyte composition

Methodology Applied

Scientific EffectComplexation:

Implementation Method 2

a porous self-supporting separator film, the porous self-supporting film having a first major surface and a second major surface

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS12170352B2Composite separator and electrolyte for electrochemical cells

Publication Date: 2024.12.17 MEDTRONIC INC

AI summary

Separator and electrolyte composites include a porous self-supporting separator film between or adjacent one or two electrolyte films. The electrolyte films may contain a glyme or mixture of glymes, LiX salt and complexing agent, such as PEO. The porous self-supporting separator film may be used dry or wetted with a liquid electrolyte composition. Solid state batteries and electrochemical cells are disclosed that include the described separator and electrolyte composites in combination with an anode and a cathode.