Regulating the Conductive Network of Graphene/Ni Composite Films toward Tunable Electromagnetic Shielding Efficiency

Smart electromagnetic interference (EMI) shielding materials with adjustable shielding efficiency (SE) hold immense importance in the field of wearable and switchable EMI shielding. However, existing materials often suffer from a constrained tunability range and inadequate stability. In this study, a highly stretchable conductive framework is fabricated by integrating Ni-doped laser-induced graphene (LIG/Ni) with silicone. Through meticulous manipulation of the LIG scanning trajectory and Ni nanoparticle (NP) deposition parameters, ordered and dense conductive pathways were formed. This ordered structure preserves the graphene's structural coherence and conductivity along the axis perpendicular to stretching, while graphene parallel to the stretching direction forms random connections, resulting in the effective regulation of electrical conductivity. Under a 200% strain, the electrical conductivity dropped to a minimum of 1.07 S/cm, and the average SE in the X-band was reduced to 2.33 dB. Upon strain release, the conductive network rapidly reconfigured, boosting conductivity to 63.6 S/m and an enhanced SE of 68.12 dB. With its highly reversible conductive network, this composite exhibits exceptional cycling stability and an expansive range of adjustable SE, thereby holding immense practical value for versatile electromagnetic protection applications.