Porous Silica Solid Electrolyte Ionic Conductivity

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Solution Overview

Problem

Current solid electrolytes used in all-solid-state lithium secondary batteries have limited ionic conductivity, hindering the development of next-generation power storage devices.

Innovation Solution

A solid electrolyte comprising porous silica with interconnected pores coated with an electrolyte containing 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI-FSI) and a lithium salt, where the molar ratio of EMI-FSI to silica is between 1.0 and 3.5, enhancing ionic conductivity and maintaining the electrolyte in a gel form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional solid electrolytes are used in all-solid-state lithium secondary batteries, then the battery structure is simplified and safety is improved, but the ionic conductivity is limited

Engineering Contradiction:

ImprovesafetyVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention uses a composite structure combining porous silica framework with EMI-FSI electrolyte coating. The porous silica provides structural stability and safety, while the EMI-FSI coating layer provides high ionic conductivity. This composite approach resolves the contradiction between safety and ionic conductivity by integrating the advantages of both materials.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention employs porous silica with controlled pore structures to create a solid electrolyte that maintains both mechanical integrity and high ion transport capability. The porous structure allows sufficient electrolyte coating while maintaining structural stability, thus achieving both safety and high ionic conductivity.

Inventive Principle:

Principle #31Porous materials

2Quantity of substance

If the molar ratio of EMI-FSI to silica is increased to improve ionic conductivity, then the electrolyte coating becomes more effective, but the electrolyte may lose its gel form

Engineering Contradiction:

Improveionic conductivityVSAvoidgel form stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The invention optimizes the molar ratio of EMI-FSI to silica within a specific range (1.0 < ratio < 3.5) to achieve the desired balance between ionic conductivity and gel form stability. This parameter optimization ensures sufficient electrolyte coating for high ion transport while maintaining the structural integrity of the gel form.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The porous silica structure acts as an intermediary framework that supports the EMI-FSI electrolyte coating. This framework allows the electrolyte to maintain its gel form while providing sufficient coating coverage for high ionic conductivity, mediating between the conflicting requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional solid electrolytes are used, then manufacturing is simpler, but the cycle, rate, and low-temperature characteristics are poor

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcycle and rate characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention applies EMI-FSI electrolyte coating to the porous silica framework in advance through impregnation, creating a pre-formed solid electrolyte with optimized properties. This preliminary action ensures that the electrolyte is uniformly distributed and properly bound to the framework, resulting in improved cycle and rate characteristics while maintaining manufacturing simplicity.

Inventive Principle:

Principle #10Preliminary action

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 proposed solid electrolyte achieves high ionic conductivity, excellent cycle, rate, and low-temperature characteristics, leading to improved electrical characteristics in power storage devices.

Implementation Method 1

an electrolyte coating inner surfaces of the plurality of pores, wherein the electrolyte includes 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide represented by EMI-FSI and a lithium salt dissolved in the EMI-FSI

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

maintaining the electrolyte in a gel form

Methodology Applied

Scientific EffectGel formation: Gel

Data Source

PatentUS11557789B2Solid electrolyte, electrode, power storage device, and method for producing solid electrolytes

Publication Date: 2023.01.17 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)

AI summary

A solid electrolyte (10) of the present disclosure includes porous silica (11) having a plurality of pores (12) interconnected mutually and an electrolyte (13) coating inner surfaces of the plurality of pores (12). The electrolyte (13) includes 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide represented by EMI-FSI and a lithium salt dissolved in the EMI-FSI. A molar ratio of the EMI-FSI to the porous silica (11) is larger than 1.0 and less than 3.5.