The shell on the nano-magnetic absorber can prevent oxidation, which is very important for its practical utilization. Generally, the nonmagnetic shell will decrease the integral magnetic loss and thus weaken the electromagnetic absorption. However, maintaining the original absorption properties of the magnetic core is a major challenge. Here, we designed novel and facile CoxFey@C composites by reducing CoxFe3−xO4@phenolic resin (x = 1, 0.5 and 0.25). High saturation magnetization value (Ms) of CoxFey particle, as a core, shows the interesting magnetic loss ability. Meanwhile, the carbon shell may increase the integral dielectric loss. The resulting composite shows excellent electromagnetic absorption properties. For example, at a coating thickness of 2 mm, the RLmin value can reach to −23 dB with an effective frequency range of 7 GHz (11–18 GHz). The mechanisms of the improved microwave absorption properties are discussed.

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Lithium dendrite growth has long been considered an obstacle to the practical application of lithium metal battery, which could be efficiently suppressed by increasing the lithiophilicity of Cu collector. Therefore, herein we developed a facile way to prepare LiCuO/Cu composite current collector, which shows better wettability with EC/EDC electrolyte than pure Cu2O layer. X‐ray diffraction (XRD) analysis shows that there is a large amount of LiCuO on the surface of the anode. The nucleation overpotential of LiCuO/Cu composite current collector is only 26 mV in the electrodeposition curve. At a current density of 1 mA/cm2, the Li−Cu cell with the as‐prepared LiCuO/Cu anode, can keep more than 85 % Coulombic efficiency for more than 125 cycles. Impedance spectra of electrodes image show that the impedance of LiCuO/Cu composite current collector is only 60 Ω at the initial stage, which can promote the transfer of Li+ at the collector surface and thus inhibit the formation of lithium dendrites on the electrode surface.

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