**3. Conclusions**

material is LiCoO2, the cathode dissolution reaction is represented by Eq. (2) [6]. Figure 15

2(s) 2 2(l) (aq) 2(aq) 2(g) (aq) 2 (l) 1 1 LiCoO H O 3HCl CoCl O LiCl 2H O

+ + ® ++ + (27)

shows a simplified diagram of li-ion batteries recycling using the electrodeposition.

2 2

118 Modern Surface Engineering Treatments

**Figure 15.** Simplified diagram of li-ion batteries recycling using the electrodeposition.

Although many groups working with Li-ion batteries recycling, the group most advanced in recycling via electrodeposition seems to be the group's researcher Eric M. Garcia. Garcia and other researchers perform a study of cathode Li-ion batteries recycling using the electrodepo‐ sition technique. Among several conclusions was shown that the largest charge efficiency found was 96.90% at pH 5.40. Furthermore, this research group conducted a detailed study of the mechanism of electrodeposition using electrochemistry quartz crystal microbalance technique (EQCM) [34]. In this case, it was assessed that at pH below 5, the electrodeposition of cobalt follows the direct mechanism (Eq. 13). For pH less than 2.70, cobalt electrodeposition occurs simultaneously with the reduction of protons to hydrogen [34]. In other work of Garcia and colleagues of research, it was explained the morphology of material electrodeposited with relation to pH. Although other research papers also focused on the cobalt electrodeposition as way of recycling battery Li-ion, Garcia's group pioneered the application of recycled cobalt. Garcia and other researchers associated the recycling of Li-ion battery to production of supercapacitor based on composite formed by cobalt oxides and hydroxides. The specific capacitances calculated from cyclic voltammetry and electrochemical impedance spectroscopy show a good agreement with the value of 625 Fg-1 [36]. Moreover Garcia et al. also proposed

The electrodeposition remains a very important topic for technology development. Through changes in operating parameters, one can obtain metallic or oxide films with different characteristics. The electrodeposited Co3O4, have an excellent supercapacitive behavior with specific capacitive value around 2700 Fg-1. The MnO2 synthesized by electrodeposition method also have very good values of supercapacitance varying between 240 and 521 Fg−1. In solar cells, the electrodeposition is a very promising method for electrodes fabrication. This is because the electrodeposition is a method simple, practical and inexpensive to produce both p-type as n-type. Moreover, with the advancement of Solid Oxide Fuel Cells development, the electrodeposition is once again an important method to be considered. In this case the electrodeposition is an excellent method for improved of electrical interconnects. Finally, there is also an environmental aspect of electrodeposition. This because the metals recycling of metals presents in spent batteries is made principally by electrodeposition method.
