Inorganic hollow microsphere based energy storage phase change composite materials with all-spectrum absorbing solar photothermal conversion for anti-/deicing

Abstract

The development of high-efficiency solar photothermal conversion and storage materials is critical to address the intermittency and randomness of solar energy. In this paper, we prepared magnéli-phase Ti_nO_2n-1(Ti₄O₇) mesoporous hollow microspheres as photothermal materials by employing titanium dioxide and polydopamine as raw materials and using the high-temperature carbothermal reduction method. The Ti₄O₇/PCMs with photothermal conversion and energy storage are synthesized by vacuum impregnation of different carbon chain fatty amines (Tetradecylamine (TDA), Hexadecylamine (HDA), and Octadecylamine (ODA)) as PCMs into the Ti₄O₇. The Ti₄O₇/PCMs exhibit superhydrophobicity and resistance to acid and alkali. The hollow structures help to minimize light reflection by enhancing light scattering and coupling, the photothermal conversion efficiencies of Ti₄O₇/TDA, Ti₄O₇/HDA, and Ti₄O₇/ODA are 89.9 %, 89.5 %, and 90.3 %, respectively, with thermal conductivities of 0.410 W·m⁻¹·K⁻¹, 0.405 W·m⁻¹·K⁻¹, and 0.418 W·m⁻¹·K⁻¹, and latent heats of 155.8 J·g⁻¹, 162.1 J·g⁻¹ and 151.9 J·g⁻¹. Meanwhile, the nanoconfinement effect of the Ti₄O₇ hollow structure effectively solves the leakage problem of fatty amine during the phase change process. The Ti₄O₇/PCMs are assembled by spraying, brushing, and molding to meet the needs of multiple working conditions, and their photothermal and electrothermal conversion performances are remarkable in applying anti-/de-icing.