Recent trends of the research activity on lithium-ion batteries in Italy

In Italy the research on lithium batteries has been active since two decades and several projects involving Universities, the ENEA government energy agency and the Arcotronics Italia SpA Company have been carried out with success. At present, in the framework of a project of national interest “Electrode and Electrolyte Nanostructured Materials for Advanced Lithium Batteries” funded by the Minister of Education, University and Research, six Academic groups have been involving in the effort to develop new electrode materials, characterized by high values of specific capacity and suitable morphology, and of new nanocomposite polymer electrolytes. The morphological conversion towards nanostructures is the strategy pursued in this project to achieve its main goal, i.e. the quantum jump in term of battery specific energy and power. In addition to improvement in specific capacity, also cost reduction and environmental compatibility are important goals. As concerns the positive electrode materials the strategy that has been following is that of replacing LiCoO2 with a less expensive and environmentally compatible materials. Accordingly, LiFePO4 has been considered very promising, although its high resistance reduces the operative capacity to fractions much below the theoretical value. To overcome this drawback the dispersion of nanometric conducting powders during the LiFePO4 synthesis process has been performed. The dispersion of nano-sized ceramic powders into the polymeric matrix is the approach which has been pursuing to obtain nanocomposite polymer electrolytes having optimized performance. As concerns negative electrode materials, research efforts have been focusing on the effect of nanometric metal powder additive on commercial graphite and on the graphite substitution with metals alloying Li, such as Sn, which have specific capacity much higher than graphite. However, these metals suffer of a limited cycle life due to the large volume changes accompanying their electrochemical process in lithium-ion batteries. To overcome this drawback the approach of reducing the metal particle size to nanometric values and of substituting the metal with intermetallic compounds or with metal oxides have been pursuing. The results confirm that the strategy to reduce the particle size to the nano scale, particularly improves the cycling stability of the electrode materials. More than 100 galvanostatic cycles without capacity loss and with near 100% coulombic efficiency have been achieved with nanometric Cu6Sn5 alloy hosted in a carbon paper current collector, which is new for this application and may be a suitable alternative to the conventional copper in that it may accommodate submicrometric particles of Cu6Sn5 in a tridimensional matrix. With the aim to give a view of the present research activity on lithium-ion batteries in Italy, the contribution of the Universities of Bologna, Camerino, Chieti, Roma “La Sapienza”, Sassari and of the Torino Politecnico, involved in the outstanding project, are reported with particular details on the results obtained at Bologna University on the negative electrode materials.