Superprotonic Conductivity of a Functionalized Metal-Organic Framework at Ambient Conditions

Xiao-Min Li; Yameng Wang; Yongbiao Mu; Jiang Liu; Lin Zeng; Ya-Qian Lan

doi:10.1021/acsami.2c00500

Superprotonic Conductivity of a Functionalized Metal-Organic Framework at Ambient Conditions

ACS Appl Mater Interfaces. 2022 Feb 23;14(7):9264-9271. doi: 10.1021/acsami.2c00500. Epub 2022 Feb 9.

Authors

Xiao-Min Li¹, Yameng Wang¹, Yongbiao Mu¹, Jiang Liu², Lin Zeng^{1

3}, Ya-Qian Lan⁴

Affiliations

¹ Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
² Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.
³ Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China.
⁴ School of Chemistry, South China Normal University, Guangzhou 510006, China.

PMID: 35138786
DOI: 10.1021/acsami.2c00500

Abstract

Seeking fast proton transport pathways at ambient conditions is desirable but challenging. Here, we report a strategy to synthesize a composite material with a polyoxometalate (POM) and an ionic liquid (IL) confined in stable metal-organic framework (MOF) channels through electrostatic interaction. The obtained SO₃H-IL-PMo₁₂@MIL-101 possesses fast proton transfer, and its proton conductivity can reach 1.33 × 10^-2 S cm^-1 at ambient conditions (30 °C, 70% relative humidity (RH)), which is the highest value among the MOF-based proton conductors operated in an ambient environment. Therefore, it has the potential of becoming a room-temperature proton conductor without a humidifier. Importantly, the composite material is further fabricated into a composite membrane for proton-exchange membrane fuel cells (PEMFCs), which can deliver a power density of 0.93 mW cm^-2 at 30 °C and 98% RH. This result can lay a fundamental basis for the application of MOF-based proton conductors in the area of electrochemical energy conversion.

Keywords: ambient condition; electrostatic interaction; functionalized metal−organic framework; proton-exchange membrane fuel cell; superprotonic conductivity.