Ordered Proton Transport Channels in a Layered Host-Guest Crystal for High-Performance Fuel Cells.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Chemistry

Background:

• Proton exchange membrane fuel cells (PEMFCs) require solid electrolytes with high proton conductivity over a broad temperature range.
• Current electrolytes face limitations in conductivity and operational temperature stability.

Purpose of the Study:

• To develop a novel solid electrolyte material for enhanced PEMFC performance.
• To investigate the proton transport mechanism in a new layered cadmium chlorophosphate crystal.

Main Methods:

• Synthesis and structural characterization of the layered cadmium chlorophosphate crystal (CdClPO4-ImH).
• Analysis of proton transport pathways using structural and theoretical methods.
• Measurement of proton conductivity under varying temperatures and humidity.
• Fabrication and testing of a H2/O2 fuel cell using the synthesized electrolyte.

Main Results:

• A new layered crystal, (C3N2H5)[CdCl(H3/2PO4)]2 (CdClPO4-ImH), was synthesized, featuring ordered 1D proton transport channels.
• A continuous hydrogen-bonding network facilitates efficient proton hopping.
• Excellent proton conductivity (2.57 × 10^-2 S cm^-1 at 90 °C and 95% RH) was achieved between -20 and 90 °C.
• An undoped membrane delivered a peak power density of 104 mW cm^-2 in a H2/O2 fuel cell.

Conclusions:

• CdClPO4-ImH demonstrates significant potential as a solid electrolyte for PEMFCs due to its broad-temperature conductivity.
• The host-guest synergy and hydrogen-bonding network are key to its efficient proton transport.
• The material offers a promising alternative for next-generation fuel cell technologies.