# Toward the Rational Design of Ion‐Conducting Ionic Liquid‐Incorporated Metal–Organic Framework Hybrids

## TL;DR

This paper reviews how to design hybrid materials combining ionic liquids and metal-organic frameworks to improve ion conductivity for solid-state batteries.

## Contribution

The paper provides a comprehensive overview of synthetic methods and factors influencing ion conduction in IL@MOF hybrids.

## Key findings

- IL@MOF hybrids show superior ionic conductivity due to ion migration in MOF pores.
- Ionic conduction is controlled by IL filling level, ion species, and MOF pore characteristics.
- Li+ ion transport in these hybrids is promising for solid-state lithium-ion batteries.

## Abstract

Solid‐state ionics have been the subject of intense research because of their possible applications as solid electrolytes for all‐solid‐state electrochemical devices. Ionic liquid‐introduced metal–organic frameworks (IL@MOFs) are an emerging class of hybrid solids with superior ionic conductivity, in which the migration of component ions of ILs in the pores is responsible for ionic conduction. In this review, we present an overview of the development of ion‐conducting IL@MOF hybrids from the perspective of synthetic methodologies to incorporate ILs into MOFs and the ion‐conducting behavior controlled by the IL filling level, ion species of ILs, and MOF structures such as pore size and pore surface state. Finally, we devote attention to the Li+‐ion conduction, especially the Li+‐ion transport number, of the pore‐encapsulated Li+‐containing ILs directed toward applications in all‐solid‐state lithium‐ion batteries.

We present the overview of the development of ionic liquid‐introduced metal–organic framework (IL@MOF) hybrids from the perspectives of synthetic methodologies to incorporate ILs into MOFs and ionic conduction controlled by IL filling level, ion species of ILs, and MOF structures such as pore size and pore surface state. Additionally, the Li+‐ion conduction, especially the Li+‐ion transport number, of pore‐encapsulated Li+‐containing ILs is presented toward applications in all‐solid‐state lithium‐ion batteries.