EBiIn-Cu-GaIn Composite Electrodes inside Microfluidic Chips

Fusible metal electrodes are one of the hot research topics today and have been more widely used in the field of microfluidics. Although many microfabrication-based techniques have been widely applied to various microstructures, current research is still unable to satisfy the use of electrodes in some extreme environments, such as the warning of electrodes in the case of thermal runaway (high temperature and high mechanical stress) in electric vehicles. In order to make the electrodes more adaptable to various environments, we have developed a method to fabricate EBiIn-Cu-GaIn composite electrodes within a single-layer microfluidic channel using a galvanic replacement reaction. The composite electrodes, which combine the advantages of miniaturization, flexibility, good mechanical properties, and high-temperature resistance, can withstand bending at 90°, stretching at 230%, and pressure at 2.7 MPa. The composite electrode was also used to fabricate a miniature heater with a heating temperature of up to 278 °C.