Composite Solid-State Electrolyte for Stable Lithium-Air Cycling

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Solution Overview

Problem

Lithium-air batteries face limitations in cycle life, energy efficiency, and safety due to the reactivity of lithium metal with liquid electrolytes and ambient components, leading to dendrite formation and unstable solid electrolyte interphase layers, which hinder their commercialization.

Innovation Solution

A solid-state electrolyte composition is developed using a polymeric matrix with inorganic nanoparticles, such as lithium and semi-metal elements, and a lithium salt, where the nanoparticles are chemically bonded within the matrix, and a silane coupling agent is used to enhance stability, applied via a solution casting method on a gas diffusion layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used with liquid electrolytes, then high theoretical energy density is achieved, but safety issues and dendrite formation occur due to reactivity with electrolyte components

Engineering Contradiction:

Improveenergy densityVSAvoidsafety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the interaction between lithium metal and electrolyte. This parameter change eliminates the reactivity issues and dendrite formation associated with liquid electrolytes while maintaining high energy density benefits

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite solid-state electrolyte consisting of inorganic nanoparticle fillers dispersed in a polymer matrix. This composite structure combines the mechanical flexibility of polymers with the ionic conductivity and stability of inorganic nanoparticles, resolving the safety-reliability contradiction

Inventive Principle:

Principle #40Composite materials

2Reliability

If solid-state electrolytes are used to improve safety, then ionic conductivity is reduced compared to liquid electrolytes

Engineering Contradiction:

ImprovesafetyVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent uses a composite structure with inorganic nanoparticles (such as Li10GeP2S12, Li10SnP2S12, or Li10SiO2S3) dispersed in a polymer matrix. The inorganic nanoparticles provide high ionic conductivity pathways while the polymer matrix provides mechanical flexibility and processability, achieving both safety and high ionic conductivity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent creates localized high-conductivity regions within the polymer matrix by dispersing inorganic nanoparticles throughout the solid-state electrolyte. These nanoparticle-rich zones serve as fast ion transport channels, ensuring high overall ionic conductivity while maintaining the solid-state safety advantages

Inventive Principle:

Principle #3Local quality

3Strength

If inorganic nanoparticles are added to polymer matrix, then mechanical strength is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent incorporates inorganic nanoparticles into the polymer matrix during the electrolyte fabrication process itself, rather than as a separate post-processing step. This preliminary integration simplifies manufacturing by combining material synthesis and reinforcement in one operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs solution casting methodology where the polymer and nanoparticle mixture is dissolved in a solvent, cast into the desired shape, and then dried to form the solid-state electrolyte membrane. This hydraulic approach simplifies the manufacturing of complex-shaped electrolytes with uniform nanoparticle distribution

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 solid-state electrolyte composition significantly improves ionic conductivity and mechanical strength, resulting in a stable potential gap and high energy efficiency over multiple cycles, outperforming traditional liquid electrolyte systems.

Implementation Method 1

The nanoparticles can also be chemically bonded within the matrix

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

a silane coupling agent is used to enhance stability

Methodology Applied

Scientific EffectSilane coupling: Adhesive

Implementation Method 3

The solid-state electrolyte composition significantly improves ionic conductivity

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 4

applied via a solution casting method on a gas diffusion layer

Methodology Applied

Scientific EffectSolution casting: Deposition (physical)

Data Source

PatentUS11967723B2Solid-state electrolyte for lithium air batteries

Publication Date: 2024.04.23 ILLINOIS INSTITUTE OF TECHNOLOGY

AI summary

A solid-state electrolyte composition for a lithium battery. The composition includes a polymeric matrix material, inorganic nanoparticles dispersed in or chemically bonded with the polymeric matrix material, and a lithium salt. The nanoparticles are formed of a compound including lithium and a different semi-metal element or metal element. Exemplary inorganic nanoparticles include a Li-rich super ionic conductor having a LixMyPzSq structural formula, wherein M refers to the different semi-metal element or a metal element.