Energy-Efficient MOF–PCM Composites: A Review of Integrated Porous Architectures for Multifunctional Thermal and Hygrothermal Energy Storage

The growing demand for sustainable and energy-efficient systems has accelerated the development of multifunctional materials capable of simultaneously storing, regulating, and conserving thermal energy. Metal–organic framework (MOF)–based phase change material (PCM) composites have emerged as promising candidates for thermal and hygrothermal energy storage because of their tunable porosity, surface chemistry, and structural adaptability. This review critically examines the relationships among MOF architecture, PCM confinement, interfacial interactions, heat and moisture transport, cycling stability, and application-specific performance. Particular emphasis is placed on the multidimensional trade-offs governing composite design. Increasing PCM loading can improve latent-heat capacity but reduce the pore accessibility required for moisture buffering, whereas the incorporation of conductive fillers can enhance heat transfer at the expense of gravimetric energy-storage density. Likewise, highly hydrophilic frameworks favor moisture regulation but may exhibit lower hydrothermal stability, while mechanically robust and scalable formulations may require compromises in porosity, PCM loading, or interfacial performance. Comparative assessment across building, solar-thermal, electronic, textile, and environmental applications further shows that no single MOF–PCM configuration can simultaneously maximize latent-heat storage, thermal conductivity, humidity control, mechanical integrity, durability, and manufacturability. Accordingly, rational MOF–PCM development should follow a multi-objective, application-specific design strategy that balances structure, interface, performance, stability, and scalability rather than optimizing a single property. These insights provide practical guidance for the development of next-generation multifunctional thermal and hygrothermal energy-storage materials.