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It is highly desirable yet challenging to develop high-performance microwave absorption materials with lightweight, thin thickness, and strong absorption capability over broad frequency ranges by simple and cost-effective methods. Herein, we design an ultralight (~54 mg cm−3) magnetic-carbon hybrid material to achieve superior microwave absorption performances. By instantaneous freezing-induced self-assembly of Fe3+, Co2+-glucose complexes on a cheap and water-removable template (i.e., NaCl), the as-made composite features 3D hierarchical porous structure and nanosheet-like carbon pore walls embedded with nanocrystalline CoFe2O4. The chemical composition can be controlled by simply altering the ratio of Co2+ (Fe3+) and glucose. Benefitting from the structural and compositional advantages, the optimized composite absorber exhibits a minimum reflection loss value of − 52.29 dB at a thin thickness of 2.0 mm and an effective absorption bandwidth reaching 5.36 GHz (12.64–18 GHz) at a low filler loading of 20 wt%. The microwave absorption mechanism survey reveals that the weak surface reflection and strong dissipation capacity induced by nanosheet-like pore walls combined with the multiple internal reflections caused by 3D hierarchical porous structure contribute to robust impedance matching and strong microwave attenuation ability. This work may offer new insights for designing highly effective magnetic-carbon microwave absorbers with low density and wide absorbing frequency.

Flexible wearable devices with highly sensitive properties have raised enormous attention in human healthcare monitoring, soft robots and smart textiles. However, the current most researches only focus on the improvement of sensing sensitivity and the acquisition of mechanical performance, regularly ignoring the significance of wearing comfort and breathability. Herein, to overcome this challenge, we developed a fibrous sensor with three-dimensional reversible conductive networks for multiple signals monitoring via novel ultrasonic-coating technology. As a strain sensor, it possessed higher sensitivity (Gauge factor = 8.96) with excellent dynamic durability (5000 cycles) and mechanical performances than other conductive gel and film based sensors, which can meet the requirement of signal detection in various extreme environments. More surprisingly, the wearable textile sensors were assembled successfully by traditional sewing technology with different shapes. These textile sensors possessed outstanding real-time signal capture capability with temperature and full-range pH at various states such as stretching and twisting. Additionally, the textile sensors can detect different degrees of human movements such as large deformation finger bending and weak deformation swallowing, which paved the way for the development of flexible wearable devices.