Aim 3: Cathodes

The Aim 3 team will focus on the reversible conversion of the positively charged metal particles, such as iron or manganese, dissolved in the electrolyte to form a solid metal-oxide cathode when the battery is being charged. On discharge, the cathode dissolves back into solution, similar to what is happening at the anode. This reversible conversion will depend on both potential energy and acidity of the electrolyte. This is part of a broad class of chemical reactions termed proton-coupled electron transfer.

The primary challenges of aqueous electrodeposition/stripping involving proton-coupled electron transfer is obtaining selectivity of the electrodeposition products under battery-relevant conditions, like high energy density, and in an electrolyte optimized for both anode and cathode. This means control of the interfacial acidity level and water, and maintenance of high electronic conductivity in the electrodeposited oxide of the electrode. Further challenges arise from competing processes, such as hydrogen atoms burying themselves in electrode crevices or the production of hydrogen and oxygen from the electrolyte’s water at both electrodes, which could destroy the battery.

This Aim 3 researchers seek to understand the elementary steps involved to obtain selectivity of aqueous metal oxide electrodeposition/stripping reactions.