Abstract: Preparation of effective electromagnetic (EM) wave absorbing composites with identical host materials and synthetic route but different guest materials remains a challenge due to diverse physicochemical properties brought about by varied guest materials. To address the above issue, the buffering effect of the buffering solution was imitated to design serially efficient EM wave absorbing composites. NiCo₂O₄ with reasonable EM absorption capacity was selected as the host material (imitating solute of buffering solution), and serial NiCo₂O₄-based composites with tunable guest materials (imitating limited external acid/base) were fabricated by means of the Maillard reaction. In consequence, five kinds of NiCo₂O₄-based EM wave absorbing composites with EAB ranging from 5.76 to 6.48 GHz were obtained. The excellent EM wave absorption performance from the buffering effect was attributed to the dynamic collaborative optimization of impedance matching characteristic and EM wave dissipation capacity due to the introduction of guest materials, which was revealed by an in-depth investigation of serial representative NC-Mo samples with consecutive addition amount variation of guest MoO₃ component in host NiCo₂O₄ materials. This work not only demonstrates a new pathway for the rapid preparation of EM wave absorbers with customized components but also sheds light on a novel strategy for the design of serial high-performance EM wave absorbing composites by means of the buffering effect.

Key words: Electromagnetic wave absorption, Spinel ferrite, Buffering effect, Maillard reaction