Reversible Surface Energy Storage in Molecular-Scale Porous Materials

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• Forcible wetting of hydrophobic pores offers a method for interfacial energy storage.
• Energy recovery via pressure-volume work during decompression is possible.
• Hysteresis in wetting/drying cycles leads to energy dissipation and reduced efficiency.

Purpose of the Study:

• To investigate how decreasing planar pore diameters affects energy recovery efficiency.
• To understand the relationship between pore size, hysteresis, and stored energy density.

Main Methods:

• Open ensemble (Grand Canonical) Monte Carlo simulations were employed.
• The study focused on the behavior of liquids within confined planar pores of varying diameters.

Main Results:

• Near-complete reversibility and improved energy recovery were achieved in pores accommodating only a monolayer of liquid.
• Small pore sizes minimized liquid/gas interface area during cavitation.
• Steep increases in infiltration pressure and reduced translational entropy were observed in tight confinements.

Conclusions:

• Reducing pore diameter is an effective strategy to minimize cycling hysteresis and enhance stored-energy density.
• This approach offers advantages over increasing liquid particle size for improving energy recovery in porous materials.