Ni₃Sn₂ alloy nanocrystals encapsulated within electrospun carbon nanofibers for enhanced microwave absorption performance

Ni₃Sn₂ nanocrystals are encapsulated in carbon nanofibers (CNFs) to form NiSn/CNFs hybrid, using a facile electrospinning method followed by thermal treatment. Compared with pure CNFs and Ni₃Sn₂ nanoparticles, the resultant NiSn/CNFs hybrid exhibits significantly enhanced microwave absorption performance in terms of high reflection loss and wide bandwidth. The introduction of Ni₃Sn₂ in CNFs can effectively regulate the microwave absorption performance of CNFs. Interestingly, an optimal content of Ni₃Sn₂ in the NiSn/CNFs hybrid leads to an unusual dielectric behavior which endows the hybrids with strong reflection loss, especially in high frequency range. When Ni₃Sn₂ loading was 52.26 wt%, a maximum reflection loss (RL) of 39.81 dB was obtained at 7.36 GHz. Moreover, a wide frequency range with RL peak value above 10 dB was achieved from 12.76 to 18 GHz. This excellent microwave absorption performance of NiSn/CNFs hybrids can be attributed to their large numbers of electrical pathways which can dissipate microwave energy into heat effectively as well as dielectric relaxation and interface scattering.