Metal Matrix–Metal Nanoparticle Composites with Tunable Melting Temperature and High Thermal Conductivity for Phase-Change Thermal Storage

Abstract

Abstract:Phase change materials (PCMs) are of broad interest for thermal storage and management applications. For energy dense storage with fast thermal charging/discharging rates, a PCM should have a suitable melting temperature, large enthalpy of fusion, and high thermal conductivity. To simultaneously accomplish these traits, we custom design nanocomposites consisting of phase change Bi nanoparticles embedded in an Ag matrix. We precisely control nanoparticle size, shape, and volume fraction in the composite by separating the nanoparticle

Engineering the Thermal Conductivity of Functional Phase‐Change Materials for Heat Energy Conversion, Storage, and Utilization

“…Although carbon materials have higher thermal conductivities, there is a possibility that metal and carbon‐based additives can react to form carbide at a high temperature for high temperature metal‐based PCMs. Additionally, adding metal additives (i.e., Bi nanoparticles) into a metal matrix (i.e., an Ag matrix) may reduce the thermal conductivity of composite due to the relatively low thermal conductivity of metal nanoparticles . Therefore, metal based PCMs do not require additional efforts to regulate thermal conductivity, which may increase the input cost and reduce the phase change enthalpy .…”

“…Except for metal and alloys, most PCMs suffer from the drawback of low thermal conductivities, which results in poor thermal charging/discharging rates. The thermal conductivities of organic PCMs and salt hydrates range from ≈0.1 to 1 W m −1 K −1 , and those of inorganic salts range from ≈0.5 to 5 W m −1 K −1 …”

“…Metal-based PCMs possess superior thermal conductivities ranging from ≈10 to 400 W m −1 K −1 , which greatly enhance the exergetic efficiency of the thermal energy storage system. [26] For example, the thermal conductivity of Sn is 66.8 W m −1 K −1 , and that of 88Al-12Si is 181 W m −1 K −1 . [27] Although carbon materials have higher thermal conductivities, there is a possibility that metal and carbon-based additives can react to form carbide at a high temperature for high temperature metal-based PCMs.…”

“…Additionally, adding metal additives (i.e., Bi nanoparticles) into a metal matrix (i.e., an Ag matrix) may reduce the thermal conductivity of composite due to the relatively low thermal conductivity of metal nanoparticles. [26] Therefore, metal based PCMs do not require additional efforts to regulate thermal conductivity, which may increase the input cost and reduce the phase change enthalpy. [4,28] Except for metal and alloys, most PCMs suffer from the drawback of low thermal conductivities, which results in poor thermal charging/discharging rates.…”

“…The thermal conductivities of organic PCMs and salt hydrates range from ≈0.1 to 1 W m −1 K −1 , and those of inorganic salts range from ≈0.5 to 5 W m −1 K −1 . [26] There are generally two approaches to tuning k PCM : filling additives [29] or encapsulating into porous matrixes or shells [30] with high thermal conductivities. Extensive available reviews related to the thermal conductivity enhancement of PCMs have been reported, which summarized the strategies for improving thermal conductivities in detail.…”