• Biomass-derived carbon (BC) materials are emerging as eco-friendly and efficient candidates for EMI shielding and EM wave absorption due to their high porosity, large surface area, and oxygen functionalities.
• The review outlines synthesis strategies for BC materials and discusses mechanisms of EM wave interference, highlighting strategies to enhance dielectric loss and impedance matching.
• BC composites with metal oxides, sulfides, or conductive polymers show significantly improved EMI shielding effectiveness and absorption performance.
• Challenges such as scalability, uniformity, and performance optimization remain, but future prospects point toward multifunctional and tunable BC-based absorbers.