Search

Passive thermal regulation has attracted increasing interest owing to its zero-energy consumption capacity, which is expected to alleviate current crises in fossil energy and global warming. In this study, a biomimetic multilayer structure (BMS) comprising a silica aerogel, a photothermal conversion material (PTCM), and a phase change material (PCM) layer is designed inspired by the physiological skin structure of polar bears for passive heating with desirable temperature and endurance. The transparent silica aerogel functions as transparent hairs and allows solar entry and prevents heat dissipation; the PTCM, a glass plate coated with black paint, acts as the black skin to convert the incident sunlight into heat; and the PCM composed of n-octadecane microcapsules stores the heat, regulating temperature and increasing endurance. Impressively, outdoor and simulated experiments indicate efficient passive heating (increment of 60 °C) of the BMS in cold environments, and endurance of 157 and 92 min is achieved compared to a single aerogel and PTCM layer, respectively. The uses of the BMS for passive heating of model houses in winter show an increase of 12.1 °C. COMSOL simulation of the BMSs in high latitudes indicates robust heating and endurance performance in a −20 °C weather. The BMS developed in this study exhibits a smart thermal regulation behavior and paves the way for passive heating in remote areas where electricity and fossil energy are unavailable in cold seasons.

Lightweight, robust, and thin aerogel films with multifunctionality are highly desirable to meet the technological demands of current society. However, fabrication and application of these multifunctional aerogel films are still significantly underdeveloped. Herein, we demonstrate a multifunctional aerogel film composed of strong aramid nanofibers (ANFs), conductive carbon nanotubes (CNTs), and hydrophobic fluorocarbon (FC) resin. The obtained hybrid aerogel film exhibits large specific surface area (232.8 m2·g–1), high electrical conductivity (230 S·m–1), and excellent hydrophobicity (contact angle of up to 137.0°) with exceptional Joule heating performance and supreme electromagnetic interference (EMI) shielding efficiency. The FC coating renders the hydrophilic ANF/CNT aerogel films hydrophobic, resulting in an excellent self-cleaning performance. The high electrical conductivity enables a low-voltage-driven Joule heating property and an EMI shielding effectiveness (SE) of 54.4 dB in the X-band at a thickness of 568 μm. The specific EMI SE is up to 33528.3 dB·cm2·g–1, which is among the highest values of typical metal-, conducting-polymer-, or carbon-based composites. This multifunctional aerogel film holds great promise for smart garments, electromagnetic wave shielding, and personal thermal management systems.

Curving 2D MXene into 1D nanofibers can effectively stop the restacking of MXene flakes, and then the nanofibers are used to construct a lightweight and multifunctional MXene/C aerogel.The MXene/C aerogels achieved an RLminof − 53.02 dB and EAB of 5.3 GHz. The radar cross-sectional reduction value of MXene/C aerogels can reach 12.02 dB m2.Integrating multiple functions such as thermal insulation, sensing, and microwave absorption into one material—MXene/C aerogel.

All-inorganic metal halide perovskites (MHPs) with the formula CsPbX3(X = Cl-, Br-, I-) have excellent photophysical properties and low-cost fabrication, offering exciting opportunities for flexible electronics. However, the suboptimal quantum yield and inferior stability of solid-state MHPs impede their diverse wearable applications. Here, a straightforward water evaporation crystallization strategy for the preparation of salt-shelled metal halide solids is proposed. The well-designed CsPbBr3@KBr material exhibits narrow green photoluminescence (full-width at half-maximum ~ 20nm), high quantum yield (87.3%), and favourable light irradiation and thermal stability. Thus, their applications in waterborne transparency inks and flexible photoluminescent films are demonstrated. Especially, they can be employed as fillers of polyvinyl alcohol (PVA) for high-performance positive friction materials in triboelectric nanogenerators (TENGs), and the output performance of the TENG is 2.3 times higher than the pristine one. As a proof-of-concept, a wearable photoluminescent sensor with a voltage response range of 0-100 kPa and a response time of 125 ms is constructed, which can potentially be served as a passive sensor-in-screen configuration to detect motions of various parts of the human body. It is believed that such metal halides will unleash the possibility of a broad variety of applications in lightweight and multifunctional wearable electronics.