Toward Enhanced S‑Band Absorption Ability via Ni Element Modification of Peach Pit Carbon

The problem of microwave pollution becomes more serious with the widespread popularity of electronic equipment; the development of microwave absorption materials has assumed critical importance. However, most reported carbon-based microwave absorption materials have no obvious absorption performance in 2–4 GHz (S band), which seriously limits their application. In this work, Ni(OH)₂-coated peach pit carbon [Ni(OH)₂/C1] is prepared by simple precipitation to achieve a minimum reflection loss (RL) value of −46.2 dB (5.6 mm, at 2.9 GHz) and absorption band cover 2.54–4 GHz in the thickness range of 3.7–6 mm in the S-band. In addition, Ni(OH)₂/C1 achieved an RL_min value of −58.05 dB (2.7 mm, at 7.68 GHz) and maximum effective absorption bandwidth (EAB) of 3.95 GHz in the range 2–18 GHz. Our work provides new insights into the microwave absorption in low frequencies and expands the application range and scenarios of carbon-based materials.