Unlocking the Potential of Polydopamine-Mediated Hybrid MXene and hBN 2D Nanosheets for Improved Thermal Energy Storage and Management Reza Eslami, Reza Daneshazarian, Nahid Azizi, Mohammad Rafieimehr, Umberto Berardi, and Hadis Zarrin* Cite This: https://doi.org/10.1021/acsaenm.4c00559 Read Online ACCESS Metrics & More Article Recommendations ABSTRACT: One challenge in phase change materials (PCM) is boosting thermal conductivity without compromising latent heat, which is essential for storing thermal energy via phase changes, such as melting and solidification. This study focuses on developing a hybrid nanoenhanced plant-based paraffin wax, by incorporating surface-modified hexagonal boron nitride (hBN) and MXene. Here, polydopamine (PDA) served as a surface and chemical modifier to enhance the compatibility and long-term stability of MXene and hBN nanosheets within the NE-PCM, which are characterized through FTIR, XPS, XRD, and TEM. The surface modification enabled the nanosheets to disperse uniformly in the PCM without needing a surfactant, and they remained stable even after 1 h of centrifugation. The results indicate that the addition of 1% of PDA@hBN/MXene to PCM led to enhancements in all thermo- physical properties, including a 25.5% increase in the latent heat of melting, a 79% increase (at 15 °C) and a 59% increase (at 40 °C) in thermal conductivity, and a 32.5% increase (in the liquid state) and a 17.8% increase (in the solid state) in specific heat capacity. These findings underscore the significant advantages of hybrid NE-PCM in enhancing the performance of thermal energy management applications such as building energy management with pipe-encapsulated methods. KEYWORDS: phase change material, hexagonal boron nitride, MXene, hybrid nanocomposite, polydopamine, thermal energy storage ■ INTRODUCTION As the world’s population and urbanization continue to grow, energy consumption in the building sector also increases, causing environmental problems such as global warming and pollution. 1 The advancement of renewable energy is closely tied to energy storage technology. Latent heat thermal energy storage (LHTES) using phase change materials (PCM) is a crucial method for balancing energy demand and supply to maintain consistent heat output after sunset and is a promising strategy for renewable energy collection and utilization. 2,3 Ideal PCMs should have minimal volume changes during phase transitions to prevent damage to containment systems. Organic PCMs (such as paraffin) typically experience minimal volume changes, while inorganic PCMs (such as salt hydrates) may show more significant variations. These materials also need good thermal conductivity, stability under cycling, and nontoxicity for long-term use in applications like waste heat recovery and solar energy storage. 4 Solid−liquid PCM have also become a popular choice for low or medium-temperature thermal energy storage applica- tions due to their desired chemical and thermal stability, as well as their low or negligible supercooling degree. 5 Paraffin Received: September 4, 2024 Revised: November 26, 2024 Accepted: December 16, 2024 Article pubs.acs.org/acsaenm © XXXX American Chemical Society A https://doi.org/10.1021/acsaenm.4c00559 ACS Appl. Eng. Mater. XXXX, XXX, XXX−XXX Downloaded via UNIV OF TORONTO on January 12, 2025 at 23:10:38 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.