Electrochemical Formation of Pb Microwires with Tunable Morphology on Liquid Metal Electrodes

Abstract

Liquid metal electrodes based on Ga are an emerging area of interest given their fluid properties which can have significant impact on electrochemical processes. Here we study metal electrodeposition, namely lead electrodeposition on the liquid metal electrodes, gallium (Ga) and galinstan (GaInSn), which was performed in two different Pb²⁺ electrolytes (PbCl₂ and Pb(NO₃)₂) to investigate any differences in the nature of the electrodeposit. Cyclic voltammetry and chronoamperometry were used to study the characteristics, kinetics, and nucleation and growth mechanisms of the electrodeposition process. Analysis of this electrochemical data, such as current density-time transients and diffusion coefficients under different potentials, revealed distinct behaviors for Pb deposition at each liquid metal and electrolyte, influencing the final morphology of the lead deposit. It was also found that the electrolyte concentration and deposition time were found to impact the morphology of the electrodeposited Pb. Scanning electron microscopy and energy dispersive X-ray spectroscopy revealed various types of Pb microstructures, including wire, branch-like, and flake-like formations, highlighting the differences in lead structural development when deposited on liquid gallium and Galinstan electrodes.