Anisotropic cellulose-based phase change aerogels for acoustic-thermal energy conversion and management.

Porous materials are usually used as sound-absorbing materials to alleviate noise pollution problems. However, the heat energy conversed from the acoustic energy is wasteful. Herein, anisotropic cellulose-based phase change aerogels (MXene/CNF-C/PEG aerogels) are fabricated by facile directional freeze casting method with anisotropic porous structure, efficient sound wave absorption, acoustic-thermal conversion and thermal management capability. MXene/CNF-C/PEG aerogels with shape stability are formed by hydrogen bonding forces between carboxylated cellulose nanofibers (CNF-C) and PEG without chemical crosslinking. The addition of MXene not only increases thermal conductive performance to 150 % but also enhances acoustic-thermal conversion ability effectively. Moreover, the directional porous MXene/CNF-C/PEG aerogels (DMCPs) possess high energy storage density (143.0 J/g) and acoustic-thermal conversion performance, which open up broad application prospect in the field of acoustic to heat energy conversion and storage.