Polymer engineering in phase change thermal storage materials

Thermal storage technology based on phase change material (PCM) holds significant potential for temperature regulation and energy storage application. However, solid-liquid PCMs are often limited by leakage issues during phase changes and are not sufficiently functional to meet the demands of diverse applications. Fortunately, it has been recognized that many polymer materials can effectively address these problems in the field of phase-change energy storage. These polymers exhibit exceptional performances and provide versatile options for energy storage applications. Due to the wide range of available polymers, different structures and properties are be utilized in various ways for energy storage purposes. This review focuses on three key aspects of polymer utilization in phase change energy storage: (1) Polymers as direct thermal storage materials, serving as PCMs themselves; (2) strategies for the development of shape-stable PCMs based on polymers, including vacuum impregnation, direct blending, chemical grafting, electrospinning, microencapsulation, and the homogeneous-toheterogeneous-strategy; and (3) polymer-enhanced multifunctional PCMs, which can exhibit additional properties such as flexibility, hydrophobicity, and photo-thermal conversion. The objective of this review is to expand the application of polymers in the field of phase change energy storage and to provide more research ideas for the development of novel, high-performance multifunctional shape-stable PCMs with excellent performances.