Fabrication of NixCo3-xS4 hollow nanosphere as wideband electromagnetic absorber at thin matched thickness

Nowadays, transition metal sulfide (TMS), especially for spinel crystal structure (A(x)B(3-x)S(4)), have been proved to be a promising electromagnetic (EM) absorber if been used to deal with the severe electromagnetic pollution. However, EM performance degradation and absorption layer thickness-decreasing at present remains a big challenge, owning to the poor EM attenuation ability. To overcome this barrier, herein we reported a NixCo3-xS4 (x = 0, 0.3, 0.6, 1.0) absorber with hollow sphere structure to realize a good EM performance with a thinner matched thickness ( < 1.5 mm). The average sizes of these NixCo3-xS4 distributed in 450-550 nm. The dielectric loss ability (epsilon '') can be boosted by tuning the molar ratio of Ni/Co, which attributes to EM performance. Additionally, hollow structure would lead to the electromagnetic multi-reflection, also benefited to EM performance. The results demonstrated that the maximum qualified absorption bandwidth (f(E)) of 3.8 GHz can be achieved for the Ni0.3CO2.7S4 sample when specimen thickness only equals to 1.3 mm.