CdPS₃ nanosheets-based membrane with high proton conductivity enabled by Cd vacancies

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Proton transport in nanochannels is vital for energy storage and conversion.
• Current materials like Nafion have limited conductivity (≤0.2 S/cm).

Purpose of the Study:

• To develop new membranes with enhanced ion conductivity for energy applications.
• To investigate the role of transition-metal vacancies in ion transport.

Main Methods:

• Assembly of membranes using two-dimensional transition-metal phosphorus trichalcogenide nanosheets.
• Characterization of proton and lithium ion conductivity under varying humidity and temperature.

Main Results:

• A Cd$_{0.85}$PS$_{3}$Li$_{0.15}$H$_{0.15}$ membrane achieved ~0.95 S/cm proton conductivity at 90°C and 98% relative humidity.
• High proton conductivity is attributed to abundant proton donors, easy desorption, and excellent hydration facilitated by cadmium vacancies.
• Superhigh lithium ion conductivity was observed in Cd$_{0.85}$PS$_{3}$Li$_{0.3}$ and Mn$_{0.77}$PS$_{3}$Li$_{0.46}$ membranes.

Conclusions:

• Transition-metal vacancies in these nanosheet membranes enable exceptionally high ion conductivity.
• These novel materials offer a promising alternative for advanced energy storage and conversion devices.