Liquid metal based stretchable magnetoelectric films and their capacity for mechanoelectrical conversion

Gallium based liquid metal alloys (GLMAs) have tremendous prospects in diverse applications, such as transient devices, soft robotics, biomedical sensing, and health monitoring, due to being endowed with compelling deformability and conductivity simultaneously. Unfortunately, most GLMA-based flexible devices require external power supply, which might cause some potential issues including additional weight, occupied space, and frequent replacement. Alternatively, self-powered concepts, by biologically converting mechanical forces to electric energy, are deemed as a promising strategy. Thus, the challenge that GLMAs are applied to self-powered system is critical and imperative. This study has demonstrated a self-powered and stretchable magnetoelectric film based on GLMAs. The magnetoelectric film is able to conduct mechanoelectrical conversion via controllable distance of electromagnetic interaction during cyclic stretching–releasing process. To investigate the mechanoelectrical conversing mechanism, an equivalent Maxwell's numerical simulation is combined with experimental results, exploring different experimental parameters. Furthermore, diverse programmed patterning of GLMAs and structure designs are utilized to tune electrical performance. It is believed that the magnetic/electrical synergistic design principle will create a new avenue for liquid metals as functional material in the development of wearable electronics with large strains.