High-Performance All-Solid-State Proton Rectifier Using a Heterogeneous Membrane Composed of Coordination Polymer and...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Achieving rational control over unidirectional proton transport is difficult due to challenges in creating asymmetry in proton-conducting materials.
• Existing methods often rely on organic polymers, which have limitations in structural design and stability.

Purpose of the Study:

• To develop a novel all-solid-state proton rectifier with enhanced unidirectional proton transport capabilities.
• To explore the use of well-defined inorganic materials for creating proton rectification.

Main Methods:

• Fabrication of free-standing membranes from a proton-conducting 2D porous coordination polymer (Cu2(CuTCPP)) and a hydroxide ion-conducting layered double hydroxide (Mg-Al-LDH(NO3)).
• Combination of these membranes to create a pH gradient within the conducting medium.
• Characterization using current-voltage measurements under controlled humidity conditions.

Main Results:

• The heterogeneous membrane demonstrated significant unidirectional proton transport.
• A proton rectification ratio exceeding 200 was achieved at 90% relative humidity in the initial voltage scan.
• This represents the highest reported ratio for all-solid-state proton rectifiers.

Conclusions:

• The combination of Cu2(CuTCPP) and Mg-Al-LDH(NO3) effectively creates a proton-rectifying device.
• The high designability and well-defined structures of these inorganic components offer a new pathway for developing solid-state proton rectifiers.
• This work provides fundamental insights into solid-state proton rectification mechanisms.