Additive manufacturing can be defined as a collection of interchangeable unitary processes that can be combined to obtain a complex product: a composite. This composite may consist of different materials such as polymer, ceramics, metal or even biological constituents. The main advantage of the additive manufacturing is that the unitary operations can be adapted to a specific and selected reaction process. In this work, electrodes of Nickel and 3-D printed polylactic acid (PLA) are produced by additive manufacturing that involves 3-D printing, assembling, compression and temperature treatment to form a stable composite. The composites and electrodes are characterized by differential scanning calorimetry (DSC), high temperature X-Ray Diffraction (HT-XRD), scanning electron microscopy (SEM) and associated techniques such as energy dispersive spectroscopy (EDS). The electrodes obtained are used to capture Sr²⁺ from aqueous solutions. The capture leads to the reduction of the Sr ion to metal on the Nickel surface as observed by SEM and EDS. The compositional changes on the electrode surfaces and morphologies are associated to each electrode reaction. The PLA stability in the reaction temperature range was studied by HT-XRD and DSC. This study is relevant because Ni is casted in PLA molds. The electroreduction is an oxidation-reduction process. It means that there are reactions in both electrodes. These reactions are studied from the morphology changes obtained by SEM and the elemental analysis done by EDS. From these analyses, the global electro-reduction reaction is proposed. The results are discussed in order to develop a mobile device oriented to the capture of Sr²⁺ in low concentration aqueous volumes.