Photothermal Mineral-Based Composite Phase Change Materials for Direct Solar Energy Utilization: A State-of-the-Art Review

Abstract

Solar energy, the most promising renewable energy, suffers from intermittency and discontinuity. Phase change material (PCM)-based energy storage technology can mitigate this issue and substantially improve the utilization efficiency of solar energy. However, most PCMs have a low photothermal conversion capacity and are prone to leaks. To address these two key issues of PCMs, fine modification and mineral encapsulation have been employed and demonstrated to be effective methods. This review summarizes the structure of mineral materials and discusses the corresponding encapsulation techniques and preparation methods for mineral-based composite PCMs. Based on this, we focus on reviewing methods for enhancing the photothermal conversion performance of mineral-based PCMs and explore their underlying mechanisms. Furthermore, we present practical application cases of photothermal mineral-based composite PCMs, analyzing their potential in photothermal applications. Finally, we discuss the challenges encountered during the synthesis, modification, and application processes of photothermal mineral-based composite PCMs, providing insights into future directions for the efficient utilization of solar energy.