Preventing Formation of Metal Dendrites During Electroplating Using External Ultrasonic Actuators

Metal dendrites are tree-like formations caused by the uneven deposition of ions onto a substrate. In electroplating, dendrites are generally undesired due to the resultant uneven and brittle surface. Furthermore, in metal batteries dendritic growth irreversibly consumes active metals and can eventually cause a short-circuit between the electrodes. Applying ultrasound to reduce dendrite growth has previously been achieved with integrated actuators. However, implementation of integrated actuation has significant drawbacks: it compromises optimal design and needs to be incorporated in early development, since retrofitting to existing designs is cumbersome or impossible. External actuation would solve these limitations. We show that external ultrasound reduces non-uniform dendrite growth during electroplating up to a threshold deposition current. Below the threshold dendrite growth was significantly inhibited and a uniform plating was formed. The results demonstrate that external ultrasonic transducers could be retrofitted to existing systems to suppress dendrite growth.