Utilizing MOFs Melt-Foaming to Design Functionalized Carbon Foams for 100% Deep-Discharge and Ultrahigh Capacity...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Meltable metal-organic frameworks (MOFs) are promising for carbon-based materials but limited by low melting points.
• Developing moldable carbon materials requires accessible MOFs with tunable properties.

Purpose of the Study:

• To introduce a MOFs melt-foaming strategy for creating functionalized carbon foams.
• To investigate the performance of Ni single atoms/quantum dots-functionalized carbon foams (NiSA/QD@CFs) as sodium metal anodes.

Main Methods:

• Developed a melt-foaming strategy utilizing flexible metal-phosphorus bonds and hydrogen bonds for MOF melting below 200 °C.
• Employed high annealing rates to induce MOF foaming, creating NiSA/QD@CFs.
• Evaluated NiSA/QD@CF electrodes in symmetrical and full sodium metal battery cells.

Main Results:

• NiSA/QD@CF electrodes demonstrated stable cycling for 1000 hours in symmetrical cells with low voltage hysteresis (98 mV at 100 mA/cm², 100 mAh/cm², 100% DOD).
• The foam structure facilitated uniform sodium deposition, and Ni single atoms/quantum dots enhanced sodium absorption.
• Full cells and anode-free cells exhibited excellent rate and cyclic performances.

Conclusions:

• The melt-foaming strategy provides a mild-processing route to liquid MOFs for electrochemical energy storage applications.
• NiSA/QD@CFs show significant potential as advanced electrode materials for high-performance sodium metal batteries.