Electromagnetic wave absorption performance and electrochemical properties of multifunctional materials: Air@Co@Co₃Sn₂@SnO₂ hollow sphere/reduced graphene oxide composites

Herein, a facile and controllable structural fabrication strategy is presented for the fabrication of multinanoshell Air@metal@intermetallic@oxide-like Air@Co@Co₃Sn₂@SnO₂ hollow spheres with a multinanoshell (HSMNS) structure using a hollow Co sphere template and a simple hydrothermal method. Composites of Air@Co@Co₃Sn₂@SnO₂ HSMNS/reduced graphene oxide (RGO) were obtained, and the electromagnetic wave (EW) absorbing properties of the composites as microwave-absorbing materials as well as the electrochemical properties as the anode electrode materials of lithium-ion batteries (LIBs) were investigated. The obtained results demonstrate that the Air@Co@Co₃Sn₂@SnO₂/RGO composite exhibited remarkable EW absorbing properties with an extremely high reflection loss of −55.49 dB and an ultrabroad effective absorption bandwidth of 5.43 GHz when loaded at only 5 wt% in a paraffin coating owing to the strengthened synergistic effects of the magnetic metal, resistive intermetallic, and dielectric metal oxide shells. In addition, the composite showed a superior performance with long-term cycling stability (960 mAh g⁻¹ after 180 cycles at a current density of 0.1 A g⁻¹) when used as the anode of an LIB. These results indicate that the composite of Air@Co@Co₃Sn₂@SnO₂ HSMNS/RGO, which exhibits light-weight, highly efficient absorbing properties, and long-term cycling stability as the anode electrode of LIBs, has a promising future in EW absorption and electrochemical fields. We hope that this strategy will provide a new method for the construction of complex multinanoshell hollow structural materials in other research fields.