In recent times, the growing demand for energy has reached new technologies for the storage of electricity where secondary electrochemical batteries have been seen as a good option to satisfy this need¹. Within the components of a cell, the electrodes are the materials that affect the performance and cost of the device. That said, it is necessary to develop materials that reduce the cost of batteries and thus expand their application for energy storage². From this point of view, metal polycyanometallates (PCMMs) could be appropriate for being employed as active cathode material because they have an open framework structure where intercalation processes of ions present in the electrolyte can occur accompanied by a redox change of a metallic center. In this work, the influence of the experimental variables of PCMM synthesis (KCu[Fe(CN)₆] or K₂Co[Mo(CN)₈]) was studied by chemical procedures (hydro / solvothermal), on the microstructure (parameters of the crystalline structure) and the charge capacity of these materials as cathodes in batteries of Metal-ion type (Metal = Li +, K +, Na +). The synthesis variables studied were: concentration of precursors, temperature and reaction time. The PCMMs were characterized physicochemically by XRD, SEM, EDX and electrochemically through cyclic voltammetry and charge / discharge curves. Additionally, button-type batteries were assembled to study the performance of these materials as cathodes. Finally, it obtained a statistical relationship between the synthesis parameters and the analyzed responses, thus finding the optimal conditions of the synthesis process to obtain the best performance of the cathodic material. The chemometric strategy used in this work can be used to optimize the cathode materials that are now used in commercial lithium batteries.

References:

1. L. Zhang y col., “Towards High-Voltage Aqueous Metal-Ion Batteries Beyond 1.5 V: The Zinc/Zinc Hexacyanoferrate System,” Adv. Energy Mater., 5, 1–5, 2015.
2. M. Omarova y col., “Nickel Hexacyanoferrate Nanoparticles as a Low Cost Cathode Material for Lithium-Ion Batteries”, Electrochimica Acta, 184, 58-63, 2015.