Heterostructured magnetic composites with exchange coupling effects are considered to be promising electromagnetic wave (EMW) absorbers. In this work, tailored heterostructures of soft magnetic ZnFe₂O₄ and hard magnetic Fe₃C are generated and tightly anchored on two-dimensional (2D) carbon nanosheets, by in-situ blowing and carbonization process of gel precursor. Nanosized soft/hard magnetic phases generate large number of heterogeneous interfaces. Density functional theory (DFT) calculations confirm the exchange coupling effect that results from the dynamic charges reconstruction of soft/hard magnetic heterogeneous interface. The synthesized Fe₃C/ZnFe₂O₄/C (FZC) shows wide effective absorption bandwidth (EAB) of 4.56 GHz and RL_min value of −65.6 dB. By layer-to-layer stacking of 2D FZC and reduced graphene oxide (rGO), the obtained flexible rGO/FZC-1 film can effectively shield 5G signals. Importantly, both the 2D morphology and abundant heterostructures restrain the diffusion of saline ions inside the FZC coatings and enhance the “maze effect”, finally improving the corrosion resistance in marine environment. This work provides advanced nanostructure integrating 2D morphology and soft/hard magnetic heterostructure with effective exchange coupling, which can simultaneously achieve the EMW stealth and high corrosion resistance.

Nanostructured silicon anodes have shown extraordinary lithium storage properties for lithium-ion batteries (LIBs) but are usually achieved at low areal loadings (< 1.5 mg·cm⁻²) with low areal capacity. Sustaining sound electrochemical performance at high loading requires proportionally higher ion/electron currents and robust structural stability in the thicker electrode. Herein, we report a three-dimensional (3D) printed silicon-graphene-carbon nanotube (3D-Si/G/C) electrode for simultaneously achieving ultrahigh areal/gravimetric capacities at high mass loading. The periodically arranged vertical channels and hierarchically porous filaments facilitate sufficient electrolyte infiltration and rapid ion diffusion, and the carbonaceous network provides excellent electron transport properties and mechanical integrity, thus endowing the printed 3D-Si/G/C electrode with fast electrochemical reaction kinetics and reversibility at high mass loading. Consequently, the 3D-Si/G/C with high areal mass loading of 12.9 mg·cm⁻² exhibits excellent areal capacity of 12.8 mAh·cm⁻² and specific capacity of 1007 mAh·g⁻¹, respectively. In-situ optical microscope and ex-situ scanning electron microscope (SEM) confirm that the hierarchically porous filaments with interconnected carbon skeletons effectively suppress the volume change of silicon and maintain stable micro-lattice architecture. A 3D printed 3D-Si/G/C-1||3D-LiFePO₄/G full cell holds excellent cyclic stability (capacity retention rate of 78% after 50 cycles) with an initial Coulombic efficiency (ICE) of 96%. This work validates the feasibility of 3D printing on constructing high mass loading silicon anode for practical high energy-density LIBs.

Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging. Owing to the excellent mechanical strength and electroconductivity, commercial carbon fibers cloth demonstrates great potential as high-performance electrodes for ions storage. Despite this, its direct application on capacitive deionization is rarely reported in terms of limited pore structure and natural hydrophobicity. Herein, a powerful metal-organic framework-engaged structural regulation strategy is developed to boost the desalination properties of carbon fibers. The obtained porous carbon fibers features hierarchical porous structure and hydrophilic surface providing abundant ions-accessible sites, and continuous graphitized carbon core ensuring rapid electrons transport. The catalytic-etching mechanism involving oxidation of Co and subsequent carbonthermal reduction is proposed and highly relies on annealing temperature and holding time. When directly evaluated as a current collector-free capacitive deionization electrode, the porous carbon fibers demonstrates much superior desalination capability than pristine carbon fibers, and remarkable cyclic stability up to 20 h with negligible degeneration. Particularly, the PCF-1000 showcases the highest areal salt adsorption capacity of 0.037 mg cm⁻² among carbon microfibers. Moreover, monolithic porous carbon fibers-carbon nanotubes with increased active sites and good structural integrity by in-situ growth of carbon nanotubes are further fabricated to enhance the desalination performance (0.051 mg cm⁻²). This work demonstrates the great potential of carbon fibers in constructing high-efficient and robust monolithic electrode for capacitive deionization.