Gallium‐assisted entropy engineering of high‐entropy oxide nanoparticles for solar/electrical dual‐mode thermal management textiles

Abstract High‐entropy oxides (HEO) offer an emerging platform for broadband photothermal conversion because multicationic disorder can simultaneously regulate crystal distortion, valence chemistry, and electronic transitions. However, synthesizing compositionally uniform high‐entropy oxide nanoparticles remains challenging, particularly for Cu‐containing spinel systems, where asynchronous precursor decomposition and unfavorable cation interactions readily induce phase segregation. Herein, we report a gallium‐assisted entropy‐engineering strategy for constructing FeCoCrNiCuGa high‐entropy oxide nanoparticles (HEO NPs). Liquid Ga nanoparticles serve not only as a reactive Ga source and nanoscale diffusion mediator but also as an enthalpy‐regulating component that lowers the thermodynamic penalty of multication mixing. The increased configurational entropy of the six‐component lattice further stabilizes the single‐phase spinel solid solution. Structural and spectroscopic analyses reveal homogeneous multielement distribution, strong lattice distortion, Raman‐active local disorder, mixed valence states, Cr 3+ /Ga 3+ ‐dominated octahedral stabilization, and Cu 2+ ‐induced Jahn–Teller distortion. With increasing cation number from FeCoGa to FeCoCrNiCuGa, the nanoparticles exhibit progressively enhanced broadband solar absorption, faster photothermal heating, and improved photothermal conversion efficiency, reaching 80.4% for the six‐component sample. Density functional theory and optical analysis suggest that the enhanced conversion originates from high‐entropy‐induced d‐orbital hybridization, bandgap narrowing, increased joint density of states, and defect‐assisted non‐radiative thermalization rather than localized plasmonic resonance. As a proof of concept, the optimized nanoparticles are integrated with MWCNT conductive networks and PDMS‐protected cotton textiles, producing a solar/electrical dual‐mode thermal management device. The textile reaches 58.9°C within 100 s under 1 sun irradiation and delivers voltage‐tunable Joule heating from 2 to 14 V, with a maximum temperature of 178.92°C. This work provides a thermodynamic and electronic‐structure design strategy for liquid‐metal‐assisted high‐entropy photothermal nanomaterials and multifunctional wearable thermal management systems. image