Highly conductive and durable electrothermal electrode through the steric confinement effect of graphene on helically intersected carbon fiber network

Abstract Flexible electrodes with good conductivity and stability during deformation are the key medical devices for thermal therapy. However, reconciling the contradiction between conductive stability and stretchability is still a challenging issue. In this study, biaxial stress field was generated by rotation extrusion technology and we successfully realized the concentric arrangement of 2D conductive graphene (GR) in the flexible tubular electrode. It is worth mentioning that this 2D stacked GR network can act as a confining space, which not only increases the contact probability of the one-dimensional filler carbon fiber (CF) in the hybrid system, reducing the percolation threshold, but also greatly improves the durability of the conductive network. The as-prepared polyethylene elastomer (POE)/g/CF electrode displayed a strain affordability of over 50%, tunable saturation temperature (Ts) of 41.8–62.3 °C with an input of 5–10 V and lower power consumption (8.0 mW/°C). Most impressively, after being compressed by 140 times (50% strain), the electrothermal performance of the flexible tubular electrode remained unchanged, which was promising in practical thermal therapy.