The major bottleneck for battery driven electric vehicles is the battery. Existing battery types all have their specific drawbacks: lead acid batteries give EV a short range of only 60 km, Na/S operate at 300 C and NiCd batteries contain poisonous Cd and are expensive. Li batteries may give EV a range of 200-300 km, operate at room temperature and are expected to be cheap. The EC programme therefore focuses on the development of different concepts for Li batteries.
The objective of this project is to develop and validate specific manganese dioxide cathodes with high energy density and good cycling behaviour for solid polymer electrolyte lithium secondary batteries manufactured by an original process developed by the CEA.
Manganese dioxide, used as a lithium intercalation compound, already presents experimental performances which are compatible with the needs of the electrical vehicle market.
- In terms of energy density, the optimization of the cathode material allows to expect ca. 120 to 150 Wh/kg within the next few years.
- Compared to the liquid electrolyte solution, the solid polymer electrolyte battery exhibits safety characteristics permitting the use of a metallic lithium electrode as anode and therefore increase the energy density.
- Many systems use toxic metals such as vanadium or reactive solvents. On the other hand, the materials used for the Lithium/MnO2 battery are environmentally harmless and the recyclability may be envisaged
- The costs of the materials used seem to be compatible with the goals of the European Community programmes (150 ECU/kWh).
Nonetheless, an optimized reversible phase still remains to be developed.
The methodology includes the synthesis and physico-chemical treatments of various simples of manganese dioxides. These are prepared by DEM/CEA, CNRS and SEDEMA, who possess the know-how for original syntheses and thermal treatments of such products.
The oxides are characterized in terms of structure, structural defects, texture, water content, chemical purity and non-stoichiometry (CEA-CARS-SEDEMA).
Specific studies are conducted to characterize the evolution on the optimized intercalation compound during the intercalation-deintercalation process, particularly with in-situ X-ray diffraction (CARS) coupled with electrochemical tests (CEA) on batteries manufactured according to an original process developed by the CEA.
Funding SchemeCSC - Cost-sharing contracts