Bicontinuous Separator Layers for Thin Solid-State Batteries

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Solution Overview

Problem

Solid-state batteries face challenges with energy density due to thick solid-state electrolytes and lithium metal causing short circuits in solid-state batteries, necessitating improved battery materials and separating layers.

Innovation Solution

A bicontinuous separating layer with a porous matrix and solid-state electrolyte, where the matrix has a porosity of 30-80% and the electrolyte occupies 60% of the porosity, providing ionic conductivity and minimizing lithium plating, using materials like aramid, ultra-high molecular weight polyethylene, and specific solid-state electrolyte materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid-state electrolytes are used to physically separate electrodes, then safety and reliability are improved, but thickness increases which reduces energy density

Engineering Contradiction:

ImprovesafetyVSAvoidthickness

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs a porous matrix structure (such as porous polymer or ceramic materials) that provides physical separation between electrodes while maintaining ion transport pathways. The porous structure reduces the effective thickness required for separation compared to solid-state electrolyte layers, thereby improving energy density while maintaining safety through physical electrode separation.

Inventive Principle:

Principle #31Porous materials

2Volume of moving object

If porous separators are used to reduce thickness, then energy density is improved, but ionic conductivity decreases

Engineering Contradiction:

ImprovethicknessVSAvoidionic conductivity

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent utilizes composite materials combining porous matrix structures with solid-state electrolyte components. This composite approach allows the separator to maintain both the physical separation function of porous structures and the high ionic conductivity of solid-state electrolytes, thereby resolving the contradiction between reduced thickness and maintained ionic conductivity.

Inventive Principle:

Principle #40Composite materials

3Volume of moving object

If lithium metal is used in negative electrodes, then energy density is improved, but short circuits occur due to lithium plating in pores and cracks

Engineering Contradiction:

Improveenergy densityVSAvoidshort circuit prevention

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent introduces a specialized separator layer as an intermediary between the lithium metal negative electrode and the positive electrode. This separator acts as a protective barrier that prevents lithium plating-induced short circuits while allowing lithium ion transport, thereby enabling the use of high-energy-density lithium metal electrodes without the short circuit problem.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If solid-state electrolyte occupies high porosity, then ionic conductivity is improved, but structural stability decreases

Engineering Contradiction:

Improveionic conductivityVSAvoidstructural stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs composite materials where a porous matrix provides structural stability and framework, while solid-state electrolyte materials filling the pores provide high ionic conductivity. This composite architecture allows the system to simultaneously achieve both structural stability from the matrix and high ionic conductivity from the electrolyte phase.

Inventive Principle:

Principle #40Composite materials

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 bicontinuous separating layer enhances ionic conductivity and prevents short circuits, improving energy density and safety in solid-state batteries while maintaining high temperature tolerance and power capability.

Implementation Method 1

The electrolyte is suitable for conducting lithium ions and/or sodium ions between the electrodes

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

The bicontinuous separating layer may include a separating matrix having pores

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS20240106072A1Bicontinuous separating layers for solid-state batteries and methods of forming the same

Publication Date: 2024.03.28 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A bicontinuous separating layer include a separating matrix having pores and a solid-state electrolyte disposed in the pores of the separating matrix. In certain variations, the bicontinuous separating layer is prepared by contacting a solid-state electrolyte liquid-state precursor with the separating matrix and heating the infiltrated separating matrix to a temperature between about 25° C. and about 300° C. The solid-state electrolyte liquid-state precursor includes a solvent and a solid-state electrolyte powder or a solid-state electrolyte precursor. In other variations, the bicontinuous separating layer may be prepared by contacting a solid-state electrolyte powder with a separating matrix to form a physical mixture and heating the physical mixture to a temperature between about 240° C. and about 500° C., where the separating matrix is defined by a polymer having a melting temperature greater than about 215° C., and the solid-state electrolyte has a melting temperature greater than about 300° C.