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

Abstract

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.