Mechanically robust and high latent heat solid–solid phase change materials <i>via</i> a H-bonding collaborative strategy for energy storage and conversion

Solid-solid phase change materials (SSPCMs) historically struggle to achieve an optimal balance between mechanical robustness and efficient thermal energy storage (TES) capacity. To overcome this limitation, we engineered a hierarchical hydrogen-bond array by integrating quadruple hydrogen-bonded UPy dimers (strong bonds) with urethane linkages (weak bonds). This synergistic network forms a crosslinked structure at room temperature, conferring exceptional mechanical strength (29.3 MPa) to the SSPCMs. Concurrently, the material achieves a high phase change component content (92 wt%) and delivers substantial latent heat (133.7 J g^-1). This dual-functionality strategy yields comprehensive performance exceeding that of most previously reported SSPCMs. Furthermore, the dynamic hydrogen-bond network imparts multiple advanced functionalities, including excellent recyclability, shape memory, and self-healing capabilities. Critically, the hydrogen-bonding mechanism mitigates the aggregation of hydroxylated multi-walled carbon nanotubes (MWCNTs), ensuring uniform dispersion within the SSPCM matrix. This advancement facilitates practical implementation in photothermal conversion and low-pressure Joule heating applications. Our supramolecular design strategy thus establishes a new paradigm for sustainable energy storage materials that simultaneously possess high mechanical integrity and significant latent heat capacity.