Suppression of dendrite formation via ultrasonic stimulation

Abstract

This research introduces a chemistry-agnostic approach to achieve rapid and degradation-free battery charging via ultrasonic agitation. An ultrasonic device operating in the megahertz range was used to stimulate electrolyte flow from outside the cell. The acoustic streaming effect accelerates ion transport from the bulk electrolyte to the electrode surface and suppresses the formation of an ion depletion zone. An experimental setup was used to optically observe the formation of dendrites when the current imposed across two zinc electrodes exceeded the limiting current. Beyond this limit, diffusion alone cannot provide sufficient ions, resulting in an ion depletion zone. It was subsequently shown that dendrite formation was reduced by over 98% when 15x the limiting current was forced across the electrodes and acoustic stimulation was delivered. Furthermore, it was shown that compared to the scenario without ultrasonic stimulation, the steady state potential was also reduced by 29%, indicating much better ion exchange between the electrodes. These findings suggest that ultrasonic stimulation can be a tool for enhancing electrochemical processes such as battery charging and discharging.