Electrochemical Nucleation and Growth of Mn and Mn-Zn Alloy from Leached Liquors of Spent Alkaline Batteries Using a Deep Eutectic Solvent.

In this work, the leaching of the active material electrodes of spent alkaline batteries was carried out using a deep eutectic solvent formed by acetylcholine chloride-urea as leaching medium. From the leaching liquors of the cathode or the cathode/anode mix, the electrochemical formation of Mn or Mn-Zn alloy, onto a glassy carbon electrode, was respectively performed by means of cyclic voltammetry and chronoamperometry techniques. The analysis of the potentiostatic current density transients was done using of models that involve the three-dimensional nucleation and diffusion controlled growth of a) bimetallic phases [Díaz-Morales et al. J. Solid. State Electrochem. 17 (2013) 345-351], in the case of the Mn-Zn alloy and b) metallic nuclei, for Mn electrodeposition [Scharifker and Mostany, J. Electroanal. Chem., 177 (1984) 13-23]. From scanning electron microscopy and EDX, it was verified that the nuclei formed were composed of Mn, or the Mn-Zn alloy depending on the leaching liquors used. [ABSTRACT FROM AUTHOR]