Copper electrodeposited in ice ionic electrolytes

Metal electrodeposition has been a subject of extensive research and has found widespread industrial applications for centuries. The use of liquid ionic electrolyte systems has become a well-established method for electrodeposition, with the vast body of literature dedicated to this system, reflecting the depth and breadth of research. While metal deposition in liquid ionic electrolytes appears to have reached its performance limits, there is potential for further improvements by exploring alternative electrolytes, such as solid ionic electrolytes. Ice ionic electrolytes represent a promising subset of ionic solid electrolytes, readily obtained by freezing liquid ionic electrolytes, leveraging the liquid-to-solid phase transition at freezing temperatures. Hence, we propose the utilization of an ice ionic electrolyte to investigate metal electrodeposition behavior within the ionic solid electrolyte framework. Here we froze a CuSO4 solution to create the ice ionic electrolyte. Remarkably, this ice ionic electrolyte exhibited excellent conductivity for electrodeposition, resulting in the formation of dense copper deposits with exceptional mechanical properties. Furthermore, we observed and analyzed unique behaviors involving cathode deposition, anode dissolution, and hydrogen evolution through microscopic examinations. This research contributes to our understanding of metal electrodeposition in ice ionic electrolytes and offers valuable insights for exploring novel avenues in electrodeposition studies.