Multifunctional phase-change materials with Ni-MOF/MXene hierarchical network for thermal energy storage, photothermal conversion, and excellent electromagnetic shielding

Abstract

Developing phase change materials (PCMs) that combine energy storage, thermal management, and electromagnetic shielding is important for improving electronic devices and renewable energy systems, meeting the growing need for efficient and compact thermal solutions. This study presents a novel multifunctional composite PCM (CPCM) that integrates energy storage, electromagnetic shielding, and photothermal-electric conversion. The composite was synthesized by electrostatically assembling a 3D Ni-MOF/MXene network, followed by vacuum-assisted impregnation of paraffin wax (PW). The PW@Ni-MOF/MXene composite exhibited a high melting enthalpy of 177.35 J g⁻¹ and crystallization enthalpy of 176.73 J g⁻¹, indicating superior energy storage capacity. Additionally, the CPCM demonstrated exceptional photothermal conversion efficiency of 96.70 %, effectively absorbing solar energy across the spectrum. The electromagnetic shielding properties of PW@Ni-MOF/MXene was also notable, with a minimum reflection loss of −51.76 dB at 17.78 GHz. The layered porous structure of the Ni-MOF/MXene network significantly enhanced the thermal conductivity of composites, reaching 0.5065 W m⁻¹ K⁻¹, 353 % higher than pure PW. These properties make the PW@Ni-MOF/MXene CPCM a promising candidate for advanced applications in thermal management, electromagnetic shielding, and photothermal-electric energy conversion systems.