The lithium-ion batteries are a promising technology for be to use how energy sources for hybrid and electrical vehicles. Those batteries have the highest energy density among the secondary batteries for mobile applications.

However, their power density is not enough for to satisfy the requirements of the electrical vehicles. For this reason, it is proposed the construction of a hybrid electrochemical device using a lithium battery and an electrochemical capacitor.

The hybrid electrochemical device combines the features of the devices used for his construction, in this case, the high power density of the electrochemical capacitor and the high energy density of the lithium battery by which this hybrid device is ideal for electrical vehicles.    

The hybridization consists in to combine the material of battery electrode and the capacitor electrode in a new hybrid electrode.

In this work, the hybrid electrode is the combination of LiFePO6 whit high surface area carbon and a metallic current collector. The LiFePO₆ was synthesized by a hydrothermal process using how precursor compound lithium hydroxide. The lithium compound was characterized using SEM and XRD.

Additionally, an electrochemical model was proposed for to predict the behavior and performance of hybrid electrode of LiFePO₆/Carbon and the hybrid device constructed with this electrode. This one dimensional model has been based in the transport phenomena, porous electrode theory, double lawyer theory and the electrochemical kinetics.

 The setting of experimental parameters of model was carried out through the electrochemical characterization of LiFePO6 using cyclic voltammetry, EIS, and stationary technics.

The model was validated at small scale in the laboratory using only the hybrid electrode.