Printable hBN Ionogel Inks for High-Resolution Flexible Electronics

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Solution Overview

Problem

Current hexagonal boron nitride (hBN) ionogel formulations are not compatible with high-resolution printing methods used in printed electronics, limiting their application in devices such as transistors, supercapacitors, and neuromorphic computing devices.

Innovation Solution

Development of aerosol-jet-printable ionogel inks using exfoliated hexagonal boron nitride nanoplatelets with a thin amorphous carbon coating and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI) ionic liquid, allowing for high-resolution printing with tunable viscosity and solid-like behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If bulk hBN ionogel formulations are used, then mechanical strength and chemical stability are improved, but printability and manufacturing precision deteriorate

Engineering Contradiction:

Improvemechanical strengthVSAvoidprintability

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The bulk hBN material is segmented into nanoplatelets through exfoliation, transforming the material from a bulk form that cannot be printed into a nanoscale form that can be aerosolized and deposited with high precision while retaining the mechanical strength benefits of hBN

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The material parameters are changed by reducing hBN to nanoplatelet scale and controlling the solid loading concentration (20-50%), which transforms the material from non-printable bulk form to printable ink form while maintaining mechanical properties

Inventive Principle:

Principle #35Parameter changes

2Strength

If high solid loading of hBN nanoplatelets is used, then mechanical strength is improved, but ink flowability and printability worsen

Engineering Contradiction:

Improvemechanical strengthVSAvoidink flowability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The ink formulation parameters are optimized by controlling solid loading within 20-50% range and adjusting ionic liquid concentration, which maintains sufficient mechanical strength while ensuring the ink remains flowable for aerosol jet printing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A composite ink system is created combining hBN nanoplatelets with ionic liquid and solvent, where the ionic liquid component provides flowability control and the nanoplatelets provide mechanical strength, achieving a balance between opposing properties

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If exfoliated hBN nanoplatelets are used, then printability is improved, but material stability deteriorates

Engineering Contradiction:

ImproveprintabilityVSAvoidmaterial stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

An ionic liquid intermediary is introduced between the hBN nanoplatelets and the solvent, forming a stable ionogel structure that prevents nanoplatelet aggregation and maintains material stability while enabling printability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A composite ionogel system is formed with hBN nanoplatelets, ionic liquid, and solvent, where the ionic liquid acts as a stabilizing matrix that maintains nanoplatelet dispersion and material composition stability during printing and application

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 printable ionogel inks exhibit high ionic conductivity and mechanical strength, enabling reliable printing and fabrication of flexible electronic devices with excellent mechanical tolerance and operational stability.

Implementation Method 1

The printable ionogel inks exhibit high ionic conductivity

Methodology Applied

Scientific EffectIonic conductivity: Conduction (electrical)

Implementation Method 2

a solid matrix material comprises exfoliated hexagonal boron nitride (hBN) nanoplatelets

Methodology Applied

Scientific EffectMechanical reinforcement: Composite Materials

Implementation Method 3

aerosol jet printing has recently attracted considerable attention for printed electronics

Methodology Applied

Scientific EffectAerosol deposition: Aerosol

Data Source

PatentUS12473451B2Printable ionogel inks and forming methods and applications of same

Publication Date: 2025.11.18 NORTHWESTERN UNIV

AI summary

One aspect of this invention relates to hexagonal boron nitride (hBN) ionogel inks using exfoliated hBN nanoplatelets as the solid matrix. The hBN nanoplatelets are produced from bulk hBN powders by liquid-phase exfoliation, allowing printable hBN ionogel inks to be formulated following the addition of an imidazolium ionic liquid and ethyl lactate. The resulting inks are reliably printed with variable patterns and controllable thicknesses by aerosol jet printing, resulting in hBN ionogels that possess high room-temperature ionic conductivities and storage moduli of >3 mS cm−1 and >1 MPa, respectively. By integrating the hBN ionogel with printed semiconductors and electrical contacts, fully-printed thin-film transistors with operating voltages below 1 V are demonstrated on polyimide films. These devices exhibit desirable electrical performance and robust mechanical tolerance against repeated bending cycles, thus confirming the suitability of hBN ionogels for printed and flexible electronics.