Facile synthesis and green high-performance electromagnetic wave absorbing composite material based on biomass cotton and Ni @ nanoporous carbon

In recent years, electromagnetic pollution has become a growing concern, and electromagnetic wave absorption materials are increasingly used to mitigate its effects. This study presents a biomass cotton/nickel MOFs-derived Ni@ nanoporous carbon@ carbon fiber (Ni@ NPC@ CF) composite material, prepared using hydrothermal and thermal decomposition methods. Microscopic observations reveal a uniform distribution of Ni@ NPC@ CF on the carbon fiber matrix. The composite exhibits multiple electromagnetic wave loss mechanisms: magnetic loss from nano‑nickel particles and electrical loss from nanoporous carbon and carbon fibers. With only a 20 % filling ratio and a thickness of 2.75 mm, the material achieves an RL_min of −67 dB and an effective absorption bandwidth (EAB) of 7.23 GHz (RL < -10 dB). This study offers a practical solution for utilizing biomass as a high-performance, cost-effective, eco-friendly, and renewable carbon-based absorbent material, providing valuable insights for developing electromagnetic wave absorbing composites.