I.LITHIUM-ION BATTERIES

This topic is aimed to the preparation and study of the ionic mobility in solid electrolytes. New electrode materials with fast Li+ de-/insertion kinetic, high reversibility and low toxicity will be obtained. It will permits the development of batteries with high energy, high power, elevate cyclability and environmental friendly.

Electrode and Electrolyte for Solid State Batteries

Objective: Preparation and study of new electrode materials and solid electrolyte with high energy values, strength, cyclability and high ionic conductivity.

Solid Electrolytes

      Structural factors which favour the ionic conductivity in compounds of the families Li_3xLa_(2/3-x)TiO₃, Li_3xLa_(1/3-x)NbO₃, Li_xSr_xLa_(2/3)-xTiO₃ and               Li_{1 + x}M _{2 + x}Al_x (PO₄)₃ (M = Ti , Ge).

Electrode materials

Regarding this theme, the following topics will be undertaken:

-> Materials for positive electrode (cathode): Spinels derived LiMn₂O₄, LiCoO₂ layered oxide derivatives and phosphate derivatives of LiFePO_4.

– Preparation of new LiNi_0.5Mn_1.5O₄-based cathodes. These materials have a very high potential (≈4.7V) and elevated energy density (≈650 mAhg^-1). For the present time, we have prepared some LiNi_0.5Mn_1.5O₄-based cathodes with cyclability >99.9% by cycle, that preserve their capacity at high currents (>90% for i ≈750mAg^-1).

– Preparation of three-dimensional (3D) electrodes comprising active materials able to reversibly de-/insert Li⁺-ions, and carbon monoliths with high electronic conductivity and porosity, the latter acting as current collector. The cathode active materials considered will be LiNi_0.5Mn_1.5O₄, LiNi_0.33Mn_0.33Co_0.33O₂ and LiFePO₄. Nanometrics MO_x and Li₄Ti₅O₁₂ will be used as anode materials.

– Preparation of 3D LiMn₂O₄ cathodes with inverse opal structure and very high capacity retention. The 3D integration of electrolyte/electrodes in an all-solid state battery will be done.

-> Negative electrode materials (anode): simple and mixed nanostructured oxides of titanium, iron.

In all cases, spectroscopic (NMR) characterization of electrolyte-electrode association by “in-situ” NMR techniques addressed to analyze factors that control Li conductivity in charge/discharge processes. Lithium ions position in the crystalline structure will be determined by neutron diffraction (ILL of Grenoble). The Li-mobility will be analyzed by pulsed field gradient nuclear magnetic resonance (PFG-NMR).

Lithium-Ion Batteries Prototypes

Objective: Design and development of prototypes for lithium-ion cells, button type batteries with excellent cyclability and low environmental impact.

– Development of high-voltage (3-5V) and high ciclability (>99.9% by cycle) Li-ionbatteries. The assemblage of these devices will facilitate the cooperation with industrial partners.