GOALI: A Comparative Study of Electrochemical Codeposition with In-Situ Electron Microscopy

Cuny City College, New York NY

Investigators

Abstract

This proposal intends to use a variety of tools, with support and collaboration from IBM, to study the nanoscale mechanics of electrochemical codeposition in real time. For the zinc-bismuth and bismuth-tellurium codeposition systems potentiostatic, galvanostatic, and pulsed control will be applied while simultaneously imaging the developing morphology of the deposited structure - in situ, within the liquid electrolyte - with good temporal resolution (30 images per second) and spatial resolution (better than 20nm). This will provide unique metrological information on the evolution of the deposit morphology at the nanoscale during electrochemical processing. This study addresses a significant gap in current understanding of codeposition processes: how morphology and stoichiometry vary under different process control regimes and electrolyte compositions. The two model codeposition systems outlined in this proposal have promise for use in energy related technologies. In electrochemical storage structures zinc anodes have long been attractive for reasons of 1) high energy density when paired with air or low-cost cathodes, 2) abundance, and 3) cost. To date secondary zinc anodes have been difficult to achieve due to a tendency toward dendritic structures. Bismuth is known to suppress hydrogen evolution in a working zinc battery and is added to increase shelf life, thus is an additive of interest to plated zinc structure. For another application, slight non-stoichiometries of bismuth telluride are the workhorse structures for thermoelectric devices, both cooling devices and electrical generators. The efficacy of the thermoelectric is determined by the relative chemistries of the complementary p and n type structures. Outside the laboratory the proposed research will serve a core topic of in-situ microscopy and seed lectures, demonstrations and online media for high school and undergraduate students.