Multimodal Solid Electrolyte Structure to Block Lithium Shorts

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Solution Overview

Problem

All solid-state lithium batteries face issues with electric shorts due to lithium metal diffusion through grain boundaries and mechanical weakness, leading to reduced performance and longevity.

Innovation Solution

A multimodal solid electrolyte design featuring a first inorganic lithium conducting oxide layer, a second inorganic lithium conducting oxide layer offset to nest within the first, and a solid polymer electrolyte layer sandwiched between them, which doubles the electrolyte surface area, restricts metallic lithium diffusion, and enhances mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ceramic oxide electrolytes are used to achieve high lithium ion conductivity, then ionic conductivity is improved, but mechanical strength deteriorates and lithium diffusion through grain boundaries causes electric shorts

Engineering Contradiction:

Improveionic conductivityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent combines ceramic oxide particles (providing high ionic conductivity) with a polymer matrix (providing mechanical strength and flexibility) to create a composite solid electrolyte. This composite structure allows the material to simultaneously achieve high lithium ion conductivity from the ceramic phase while maintaining mechanical integrity and preventing dendrite formation through the polymer phase.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent creates a heterogeneous structure where ceramic oxide particles are distributed throughout the polymer matrix, giving different regions different properties. The ceramic-rich regions provide high ionic conductivity pathways, while the polymer-rich regions provide mechanical strength and dendrite resistance, allowing local optimization of both conductivity and strength.

Inventive Principle:

Principle #3Local quality

2Strength

If solid polymer electrolytes are used to improve mechanical strength and prevent lithium diffusion, then reliability is improved, but ionic resistance increases and battery performance decreases

Engineering Contradiction:

Improvemechanical strengthVSAvoidionic conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent incorporates ceramic oxide particles into the polymer electrolyte matrix to create a composite material that enhances ionic conductivity. The ceramic phase provides additional lithium ion conduction pathways, compensating for the higher ionic resistance of the pure polymer while maintaining the mechanical strength and dendrite-blocking properties of the polymer matrix.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If ceramic oxide electrolytes are used to achieve high volumetric energy density, then energy density is improved, but manufacturing complexity increases due to high temperature sintering requirements

Engineering Contradiction:

Improvevolumetric energy densityVSAvoidmanufacturing process

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent replaces the high-temperature sintering process (mechanical/thermal system) with a lower-temperature polymer matrix formulation. Instead of requiring extreme temperatures to densify ceramic electrolytes, the invention uses a polymer binder that can be processed at much lower temperatures, simplifying manufacturing while maintaining high volumetric energy density through the composite structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 multimodal solid electrolyte design significantly reduces internal resistance, improves mechanical durability, and extends battery life by preventing electric shorts and enhancing lithium ion migration.

Implementation Method 1

restricts the diffusion of metallic lithium

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

second inorganic lithium conducting oxide material

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11855252B2Multimodal electrolyte design for all solid state batteries

Publication Date: 2023.12.26 NISSAN MOTOR CO LTD

AI summary

A multimodal solid electrolyte for a solid-state lithium electrochemical device comprises a first layer formed of first rows each having an anode-facing base with an apex extending opposite an anode, the first layer being a first inorganic lithium conducting oxide material, and a second layer formed of second rows each having a cathode-facing base with an apex extending opposite a cathode, the second layer being a second inorganic lithium conducting oxide material, wherein the second rows are offset from the first rows such that the apex of each second row nests within the first rows. A solid polymer electrolyte layer is sandwiched between the first layer and the second layer.