Ricerc@Sapienza

Lithium-ion batteries (LIBs) have received increasing interest thank to their high potential for providing efficient energy storage and low environmental impact. However, there are still concerns about the safety of LIBs; the increased number of explosion and fire accidents has raised significant attention in LIBs safety, limiting their commercialization and applications.
A battery consists of anodic and cathodic compartments separated by an electrolyte. Usually this electrolyte is based on organic solvents dissolving suitable lithium salts, which guarantees the well-known high power densities and energies characteristic of LIBs. However, these organic electrolytes are volatile and flammable, posing a several safety issues for the LIBs use.
A strategy to reduce the safety hazard in these devices is the replacement of the conventional liquid electrolytes with solid polymer electrolytes (SPE).
Among all solid polymers studied, the ion exchange membrane can be considered an interesting choice due to its single-ion property which can facilitate the fast Li+ transport and guarantees a Li+ transference number equal to one. Besides, this type of membranes does not require the addition of lithium salts which are unstable and corrosive. In this field, perfluoro-sulfonated polymers, such as Nafion membrane (DuPont) widely used as electrolyte in low temperature Fuel Cells, could be an innovative approach for the development of future polymer electrolytes for LIBs.
In this project, particular efforts will be devoted to develop and characterize advanced Li+-conducting Nafion membrane with higher ionic conductivity and stability. Powerful physical chemical and electrochemical characterizations will be used. Composite Nafion-Li membranes, obtained by incorporating functional inorganic additives, will be also considered. The electrochemical performances of the proposed electrolytes will be studied in Li/Li symmetric cells and in secondary cells using LiFePO4 as cathode materials.