Anodes for Li-ion Batteries based on electrodeposited Tin in Deep Eutectic Solvents

L.A. AZPEITIA; M.G. ORTIZ; C.A. GERVASI; A. VISINTIN; A.E. BOLZÁN

Brno

Congreso; 23rd ABAF Advanced Batteries, Accumulators and Fuel Cells; 2022

Considering the potential value of tin and tin compounds as materials for Li-ion batteries anodes, the simplicity of the electrodeposition techniques and the increasing interest in deep eutectic solvents as strategic green solvents, we studied the preparation of tin electrodes of different structures and composition. For this purpose, anodes based on copper foils and copper foams were used [1]. Copper foams were prepared in our laboratory by electrodeposition of copper from copper sulphate solutions under galvanostatic conditions, and heat treated to improve their mechanical characteristics. Both, foams and foils, were covered by a thin film of electroreduced graphene oxide (ERGO) formed by the drop-casting method [2]. The purpose of this highly conductive layer was to separate copper substrate from tin electrodeposit to hinder the diffusion of tin atoms into the copper lattice with the subsequent formation of intermetallics. Afterwards, tin anodes were prepared by electrodeposition from a choline chloride + tin chloride 1:2 molar deep eutectic solvent by applying a pulse plating technique under galvanostatic conditions [3]. Four different types of electrodes were synthesised and tested: i) copper foil + ERGO + tin; ii) copper foil + ERGO + tin oxide; iii) copper foam + ERGO + tin and iv) copper foam + ERGO + tin oxide. Electrodes consisting of tin oxide were prepared by electro-oxidation in 0.05M KClO4 applying a galvanostatic double-pulse routine by stepping from 5 mA/cm2 for 1 s, to 0 mA/cm2 for 1s, during t = 1200 s. Results show significant improvement on the electrodes performance after changing from a smooth to a 3D structure and from tin to tin-oxide electrode.