Facile Fabrication of Low-Impedance, Highly Conformal Epidermal Electrodes Based on Laser-Induced Graphene-Silver...

Long-term and high-fidelity electrophysiological (EP) signal monitoring with conformal epidermal electrodes with low contact impedance and robustness against motion artifacts is of great significance for health monitoring and human-machine interfaces. However, the low-cost yet scalable fabrication of large-area electrodes and arrays with these desired properties remains challenging. Here, a facile strategy is reported to fabricate large-area, highly conformal, and low-impedance epidermal electrodes based on highly porous and conductive laser-induced graphene (LIG) nanocomposites. The patterned superhydrophilic LIG allows the self-selective wetting of silver ionic solutions into the porous structure, followed by reduction to form LIG-Ag nanocomposites with significantly reduced sheet resistance (from 50 to 0.06 Ω/sq) and also the skin contact impedance. Subsequent transfer of the nanocomposites onto an ultrathin (13 µm) styrene-ethylene-butylene-styrene (SEBS) substrate results in durable, highly conformal, and low-impedance epidermal electrodes even after storage for over 8 months. The resulting electrodes demonstrate superior signal-to-noise ratio (SNR) and resistance against motion artifacts for EP signal monitoring. The twelve-lead ECG monitoring and biopotential-based control of a robotic hand demonstrate the practical utility of these electrodes for clinical health monitoring and human-machine interactions.