Coordination polymer glass from a protic ionic liquid: proton conductivity and mechanical properties as an electrolyte.

Tomohiro Ogawa,You-Lee Hong,Kazuki Takahashi,Yusuke Nishiyama,Koji Ohara,Sanjog S Nagarkar,Satoshi Horike

doi:10.1039/d0sc01737j

Abstract

High proton conducting electrolytes with mechanical moldability are a key material for energy devices. We propose an approach for creating a coordination polymer (CP) glass from a protic ionic liquid for a solid-state anhydrous proton conductor. A protic ionic liquid (dema)(H2PO4), with components which also act as bridging ligands, was applied to construct a CP glass (dema)0.35[Zn(H2PO4)2.35(H3PO4)0.65]. The structural analysis revealed that large Zn–H2PO4−/H3PO4 coordination networks formed in the CP glass. The network formation results in enhancement of the properties of proton conductivity and viscoelasticity. High anhydrous proton conductivity (σ = 13.3 mS cm−1 at 120 °C) and a high transport number of the proton (0.94) were achieved by the coordination networks. A fuel cell with this CP glass membrane exhibits a high open-circuit voltage and power density (0.15 W cm−2) under dry conditions at 120 °C due to the conducting properties and mechanical properties of the CP glass.

Highlights

Proton conductive materials are important components of various electrochemical devices.[1,2,3] One signi cant device is the fuel cell, and anhydrous proton conductors as electrolytes working at 120–200 C have long been in high demand.[4]
The structural analysis revealed that large Zn–H2PO4À/H3PO4 coordination networks formed in the coordination polymer (CP) glass
The amorphous compound containing Zn2+, dema, and H2PO4À was synthesized by neutralization of zinc oxide (ZnO), diethylmethylamine and phosphoric acid (H3PO4) (Scheme S1† top)

Summary

Introduction

Proton conductive materials are important components of various electrochemical devices.[1,2,3] One signi cant device is the fuel cell, and anhydrous proton conductors as electrolytes working at 120–200 C have long been in high demand.[4]. EDGE ARTICLE Satoshi Horike et al Coordination polymer glass from a protic ionic liquid: proton conductivity and mechanical properties as an electrolyte

Results

Conclusion