Electrically Reconfigurable Phase Change Gly/Hydrogel for Solar‐Thermal Battery

ABSTRACT Phase change materials (PCMs) offer great promise for sustainable thermal energy storage, yet their practical deployment is hindered by unstable supercooling, inefficient solar harvesting, and lack of on‐demand energy release. Here, we propose a novel solar‐thermal battery using an electrically reconfigurable rigid‐flexible switchable phase change gly/hydrogel (PAM/SAT‐CQD gly/hydrogel) for ultra‐high solar harvesting and long‐term energy storage. The PAM/SAT‐CQD gly/hydrogel achieves unprecedented metastability down to −30°C with a supercooling degree of up to 88°C due to the H‐bonded solvation network of glycerol, enabling long‐term energy storage without accidental crystallization. Crucially, we develop a novel electrically reconfigurable crystallization technique, enabling on‐demand energy release of the supercooled PAM/SAT‐CQD gly/hydrogel to realize smart thermal management. Moreover, the PAM/SAT‐CQD gly/hydrogel also exhibits exceptional photothermal conversion efficiency over the full solar spectrum due to the non‐radiative relaxation of carbon quantum dots (CQDs). Importantly, the strong hydrogen bounding network endowed PAM/SAT‐CQD gly/hydrogel with excellent water retention and reabsorption capability. These attributes, supported by a robust hydrogen‐bonding network and non‐radiative photothermal mechanisms, make our PAM/SAT‐CQD gly/hydrogel ideal for applications in solar‐thermal battery, as well as wearable thermal management and intelligent thermal regulation systems, offering a scalable solution for renewable energy integration.