This paper provides a review of the solid–liquid phase change materials (PCMs) for latent heat thermal energy storage (LHTES). The commonly used solid–liquid PCMs and their thermal properties are summarized here firstly. Two major drawbacks that seriously limit the application of PCMs in an LHTES system, that is, low thermal conductivity and liquid leakage, are discussed. Various methods for enhancing the thermal conductivity and heat transfer of solid–liquid PCMs are explained. Previous studies regarding form‐stable composite PCMs and microencapsulated PCMs are also presented. Furthermore, applications of the solid–liquid PCMs used in LHTES and thermal management systems are introduced and analyzed. Finally, future outlooks and research topics are proposed.

Phase change materials (PCMs) offer great potential for realizing zero-energy thermal management due to superior thermal storage and stable phase-change temperatures. However, liquid leakage and solid rigidity of PCMs are long-standing challenges for PCM-based wearable thermal regulation. Here, we report a facile and cost-effective chemical cross-linking strategy to develop ultraflexible polymer-based phase change composites with a dual 3D crosslinked network of olefin block copolymers (OBC) and styrene-ethylene-butylene-styrene (SEBS) in paraffin wax (PW). The C-C bond-enhanced OBC-SEBS networks synergistically improve the mechanical, thermal, and leakage-proof properties of PW@OBC-SEBS. Notably, the proposed peroxide-initiated chemical cross-linking method overcomes the limitations of conventional physical blending methods and thus can be applicable across diverse polymer matrices. We further demonstrate a portable and flexible PW@OBC-SEBS module that maintains a comfortable temperature range of 39–42 °C for personal thermotherapy. Our work provides a promising route to fabricate scalable polymer-based phase change composite for wearable thermal management.