hBN Gel Electrolytes Balancing Strength and Ionic Conductivity

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Solution Overview

Problem

Current solid-state electrolytes for lithium-ion batteries face challenges such as low ionic conductivity, high interfacial resistance, and cumbersome processing, while liquid electrolytes are highly flammable, posing safety risks.

Innovation Solution

Development of high-modulus gel electrolytes using exfoliated hexagonal boron nitride (hBN) nanosheets coated with carbon, mixed with an ionic liquid, which enhances mechanical properties and maintains high ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid-state electrolytes are used to eliminate flammable organic solvents, then safety is improved, but ionic conductivity and mechanical properties deteriorate

Engineering Contradiction:

ImprovesafetyVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses composite materials by combining ionic liquids with gelling matrices (polymers or ceramic particles) to create ionogels that exhibit both solid-state safety and liquid-like ionic conductivity. The composite structure allows the ionic liquid to provide high ion transport while the matrix provides mechanical strength and stability.

Inventive Principle:

Principle #40Composite materials

2Strength

If solid matrix loading is increased to enhance mechanical strength, then resistance to lithium dendrite growth is improved, but ionic conductivity deteriorates

Engineering Contradiction:

Improvemechanical strengthVSAvoidionic conductivity

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating a hierarchical structure where the gelling matrix provides mechanical strength at the macro scale while the ionic liquid channels maintain high ionic conductivity at the micro scale. The matrix is designed to provide structural support without completely blocking ion transport pathways.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If conventional liquid electrolytes are used, then ionic conductivity is maintained, but flammability and safety risks worsen

Engineering Contradiction:

Improveionic conductivityVSAvoidflammability

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful flammability of conventional liquid electrolytes into a benefit by using ionic liquids that are inherently non-flammable. The ionic liquid composition eliminates the safety risks of organic solvents while maintaining the desired ionic conductivity through its unique molten salt structure.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Object-affected harmful factors

If currently available solid-state electrolytes are used, then flammability is eliminated, but processing complexity and interfacial resistance worsen

Engineering Contradiction:

ImproveflammabilityVSAvoidprocessing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies universality by designing ionogel electrolytes that simultaneously perform multiple functions: they act as both the electrolyte medium and the separator, eliminating the need for separate porous membrane components. This multi-functionality simplifies the overall device structure and processing while maintaining safety.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 hBN nanosheet-based gel electrolytes offer improved mechanical strength by two orders of magnitude, retain high ionic conductivity, and provide thermal stability up to 175°C, enabling safe and efficient operation of solid-state rechargeable batteries.

Implementation Method 1

exfoliated hBN nanosheets are produced

Methodology Applied

Scientific EffectExfoliation:

Implementation Method 2

Ionic liquids offer several advantages including nonflammability, negligible vapor pressure, and high thermal and electrochemical stability

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 3

impart exceptional thermal stability that allows high-rate operation of solid-state rechargeable lithium-ion batteries at temperatures up to 175° C.

Methodology Applied

Scientific EffectThermal stability: Thermal Insulation

Data Source

PatentUS12407019B2Gel electrolytes for electrochemical devices, fabricating methods and applications of same

Publication Date: 2025.09.02 NORTHWESTERN UNIV

AI summary

This invention discloses high-modulus, ion-conductive gel electrolytes and methods of making the gel electrolytes and electrochemical devices. The gel electrolytes include an ionic liquid and nanosheets mixed in the ionic liquid. The nanosheets in one example include exfoliated hexagonal boron nitride (hBN) nanosheets. Compared to conventional bulk hBN microparticles, exfoliated hBN nanosheets improve the mechanical properties of the gel electrolytes by about 2 orders of magnitude, while retaining high ionic conductivity at room temperature. Moreover, exfoliated hBN nanosheets are compatible with high-voltage cathodes, and impart exceptional thermal stability that allows high-rate operation of solid-state rechargeable lithium-ion batteries at high temperatures.