Polymeric Electrolyte Additives for Suppressing Zinc Dendrite Formation in Rechargeable Batteries with Zinc Anodes

Rechargeable zinc-air batteries are attractive because they utilize non-flammable aqueous electrolytes and offer high energy densities. However, a major roadblock in the development of rechargeable zinc-anodes is the dendritic morphology evolution during zinc electrodeposition (i.e., during battery charging). Zinc dendrites are a major source of capacity loss and early cell failures.

In the present talk, we will demonstrate the use of polymeric additives, such as polyethylenimine, as electrolyte additives for effectively suppressing dendrite formation during zinc electrodeposition. Dendrite suppression by additives will be characterized using in situ optical microscopy. Steady-state and transient electrochemical polarization measurements on a rotating disk electrode, combined with electrochemical quartz crystal microgravimetry will be used to unravel the mechanism by which additives suppresses zinc dendrite growth. Additive injection studies implemented in a rotating disc electrode configuration, coupled with diffusion-adsorption modeling, will be discussed as a reliable technique for precisely measuring the diffusion coefficient and adsorption rate constant of aforementioned polymeric additives. These additives' properties provide insights into the rate-controlling processes responsible for additives-assisted zinc dendrite suppression.