Experimental Evaluation of Redox Couples of Copper Complexes Based on 1,10‐Phen and 2,2‐Bpy in an Aprotic Medium: In Search of Alternatives for Electrochemical Energy Storage Systems

This manuscript focuses on the study of copper salts and complexes, contemplated for their use in RFB. In the first instance, the copper redox pairs were evaluated in CuCl 2 and Cu(NO 3 ) 2 salts in acetonitrile and later the corresponding syntheses were performed to form complexes of the same salts using 1,10‐phen and 2,2‐bpy as ligands. The electrochemical evaluation was carried out using cyclic voltammetry techniques in parallel with spectrophotometric techniques. In addition, EIS studies were carried out and the characterization of the surface electrodes with SEM after electrolysis at negative potentials is also shown. The cyclic voltammetry diagrams show a good reversibility of the copper redox couple when a graphite electrode is used in media without complexes. In addition, the deposits present well‐defined and uniform geometries over the entire surface of the working electrode. However, the UV–vis tests show a low stabilization of the Cu + species in the noncomplexed species. For the synthesized complexes, good reversibility of the Cu(I) species is observed in cyclic voltammetry. A correct configuration with the use of Copper and graphite in copper salts with and without complexing allows obtaining a cell potential of 1.2 V, a quite competitive potential for copper batteries.