Printing Composites with Salt Hydrate Phase Change Materials for Thermal Energy Storage

Area of Science:

• Materials Science
• Chemical Engineering
• Energy Storage

Background:

• Salt hydrate phase change materials (PCMs) are crucial for thermal energy storage in renewable energy systems.
• Widespread adoption is hindered by issues such as undercooling, phase separation, and container corrosion.
• Developing stable and efficient salt hydrate PCMs is essential for advancing energy storage technologies.

Purpose of the Study:

• To develop a novel additive manufacturing method for creating noncorrosive salt hydrate composites.
• To integrate nucleating agents and thermally conductive additives into salt hydrate PCMs.
• To enhance the thermal cyclability and reduce undercooling of salt hydrate PCMs.

Main Methods:

• Utilized direct ink writing (DIW) additive manufacturing to print salt hydrate composites.
• Prepared salt hydrate particles from nonaqueous Pickering emulsions to formulate thixotropic inks.
• Incorporated polymer dispersions in toluene as the matrix, with salt hydrates acting as rheological modifiers.
• Cured the printed composites via solvent evaporation under ambient conditions.
• Integrated carbon black to enhance thermal conductivity.

Main Results:

• Successfully printed and cured salt hydrate composites containing up to 70 wt % salt hydrate.
• Demonstrated reliable thermal cyclability over 10 cycles with suppressed undercooling compared to bulk salt hydrate.
• Maintained structural integrity and thermal performance during melting and solidification.
• Showcased versatility using magnesium nitrate hexahydrate (MNH) and zinc nitrate hexahydrate (ZNH).
• Enhanced thermal conductivity by at least 33% with the addition of carbon black.

Conclusions:

• Additive manufacturing offers a versatile platform for creating advanced salt hydrate phase change materials.
• The DIW technique effectively addresses undercooling, phase separation, and corrosion issues.
• These tailored composites provide customizable thermal properties for targeted energy management applications.