Multiple H‐Bonding Cross‐Linked Supramolecular Solid–Solid Phase Change Materials for Thermal Energy Storage and Management

Abstract Solid–solid phase change materials (SSPCMs) are considered among the most promising candidates for thermal energy storage and management. However, the application of SSPCMs is consistently hindered by the canonical trade‐off between high TES capacity and mechanical robustness. In addition, they suffer from poor recyclability due to chemical cross‐linking. Herein, a straightforward but effective strategy for fabricating supramolecular SSPCMs with high latent heat and mechanical strength is proposed. The supramolecular polymer employs multiple H‐bonding interactions as robust physical cross‐links. This enables SSPCM with a high enthalpy of phase transition (142.5 J g⁻¹), strong mechanical strength (36.9 MPa), and sound shape stability (maintaining shape integrity at 120 °C) even with a high content of phase change component (97 wt%). When SSPCM is utilized to regulate the operating temperature of lithium‐ion batteries, it significantly diminishes the battery working temperature by 23 °C at a discharge rate of 3 C. The robust thermal management capability enabled through solid–solid phase change provides practical opportunities for applications in fast discharging and high‐power batteries. Overall, this study presents a feasible strategy for designing linear SSPCMs with high latent heat and exceptional mechanical strength for thermal management.