A multi-mode cellulose acetate/MXene Janus film with structure enhanced self-reflection, selective emission and absorption for cooling and heating

Passive radiative thermal management has been recognized as one of the most promising energy-saving technologies to provide thermal comfortable environment. However, static function and complex production process limit its application. Herein, we propose a simple strategy to achieve the integration of radiative cooling, radiative heating, and active electro-thermal heating. It is worth stressing that the radiative cooling is only based on the self-reflective structure and self-emissive molecular property of cellulose acetate electrospun membrane. In cooling mode, the average temperature of Janus film outdoor is 9.4 degrees C lower than commercial cotton fabric. Meanwhile, radiative heating and active heating stem from the photothermal and electrothermal performance of MXene. In heating mode, the average temperature of Janus film is 40 degrees C higher than cotton fabric. Flipping the Janus film allows for dynamic thermal management. In short, the scalable and universal strategy paves the way for the development of dynamic thermal-regulating technology.