Hierarchically engineered mineral frameworks for photothermal synergistic phase change microspheres: enabling high-efficiency building thermal regulation

Buildings represent a significant global energy consumer, with heating and cooling accounting for the dominant demand sector, where renewable energy penetration remains insufficient. Solar energy, as the most abundant clean resource, necessitates advanced materials to address intermittency and low energy density challenges. While phase change materials (PCM) integrating photothermal conversion and thermal storage functions offer critical solutions for energy-efficient buildings, their practical implementation is hindered by inherent limitations: low thermal conductivity compromises heat transfer efficiency, and leakage during phase transitions undermines system reliability. These deficiencies impose fundamental deployment barriers in construction applications demanding precise thermal regulation. To transcend these limitations, we engineer hierarchical mineral microspheres featuring three key innovations: a dual-scale thermal network via synergistic integration of graphite nanosheets and silver nanowires (AgNWs) into porous attapulgite (ATP), where graphite nanosheets establish fundamental heat conduction pathways and AgNWs act as ‘high-speed channels’ to bridge the contact thermal resistance between nanosheets, overcoming conductivity barriers of carbon-only systems; molecular-level leakage confinement through biomimetic sodium alginate/CaCl₂ cross-linking, forming plant cell-inspired core-shell structures; and cement-compatible fabrication enabled by vacuum-assisted PCM loading for direct construction material integration. The optimized composite (P-PVA-AAGC) achieves exceptional thermal storage capacity (melting enthalpy: 112.9 J/g; solidification: 102.2 J/g) and exhibits a 3-fold extension in phase transition duration (35–30 °C) versus P-ATP. Crucially, cement-integrated microspheres demonstrate unprecedented thermal regulation in functional building blocks, validating scalable deployment. This architecture establishes a new paradigm for energy-saving building envelopes and solar thermal systems, enabling high-efficiency thermal regulation in functional building blocks and addressing critical sustainability gaps in construction.