Highly Flexible and Conductive Electrodes through Combining Honeycomb and Butterfly Pattern Bio‐Inspired Structure for ECG Signal Recording

Abstract Recent advances in the development of flexible electronic devices have increased the demand for flexibility and conductivity. However, there is still a significant challenge to manufacture flexible electrodes featuring satisfactory mechanical and conductivity performance simultaneously. In this paper, based on synergistically combining theoretical structural design and screen printing, a new flexible electrode with butterfly‐shaped honeycomb (BSH) negative Poisson's ratio (NPR) structure through combining honeycomb and butterfly pattern bio‐inspired structure is designed and fabricated. And the flexibility and conductivity of different substrate electrodes are investigated. Results demonstrate that flexible electrode of polyamide (PA) substrate with BSH‐NPR structure can effectively boost the conductivity during the large deformation process, resulting in higher bending‐resistant (the resistance is only 4.1 Ω at 180°), fatigue‐resistance (only 4.5 Ω after 1000 cycles), stretching‐resistance (only 20.3 Ω at 20% strain), and self‐recovery (releasing strain enables re‐joining, namely, conductive) properties. Particularly, the electrode is still conductive when the strain of that is 40% and shows promising mechanical properties. Electrocardiography (ECG) signals recorded on the volunteer's chest, fingertips (no bending), and knuckles (repeated bending) are successfully exhibited with superior accuracy and long‐term stability for flexible electrode fabricated in this paper, demonstrating greater potential in biological signal monitoring applications.