Sunlight‐Triggered Polymerization of Anti‐Freezing PADOCFe Ionogels for Low‐Grade Heat Harvesting, Device Cooling, and Energy Storage

ABSTRACT The high energy consumption of artificial intelligence (AI) hardware remains a major limitation; harvesting and converting its waste heat using multifunctional ionogels offers an energy‐saving pathway. However, ionogels possess low‐grade heat harvesting, device cooling and energy storage fabricated under nature conditions remains challenging. Herein, we propose a novel sunlight‐triggered polymerization with solvent exchange to construct multifunctional poly(acrylic acid‐co‐acryloyloxyethyl trimethylammonium chloride)/oxidized curdlan/Fe 2 (SO 4 ) 3 (PADOCFe) ionogels. OC (27.3% carboxyl content) functions as a bio‐accelerator and photothermal initiator, reducing the activation energy of PAD polymerization from 103.2 to 69.5 kJ mol −1 and enabling sunlight‐triggered polymerization under ambient conditions. Subsequent Fe 3 ⁺/SO 4 2 − solvent exchange induces Hofmeister salting‐out and metal‐ligand coordination, yielding densely networks with high toughness (2.22 MJ m −3 ), ionic conductivity (8.63 S m −1 ) and anti‐freezing stability (−20°C). Strikingly, PADOCFe acts as ionic medium for thermoelectric harvesting and evaporative cooling, maintaining a stable Seebeck coefficient of 0.47 mV K −1 after 10 cooling‐absorption cycles. Integrated with a charging smartphone, it reduces surface temperature from 46.4 to 35.6°C while generating 1.8 mV at △ T ≈ 2.0°C. As a supercapacitor electrolyte, it delivers specific capacitance of 106.3 F g −1 and 90.4% retention after 1000 cycles. These sunlight‐triggered, three‐in‐one ionogels provide a promising route to mitigating energy challenges of AI hardware in flexible electronics.