The goal of the research Project is the development of suitable anode, electrolyte and cathode materials which can be combined in ambient temperature rechargeable batteries. Particular attention will be paid to those batteries in which both electrodes intercalate reversibly lithium and show a back and forth motion of their lithium atoms during cell charge and discharge (lithium ion batteries, rocking-chair batteries).
The performance of the different cell components will be improved in order to obtain safer, longer lasting, cheaper and less polluting batteries.
The scientific objectives of the Project include: preparation of new binary and ternary oxide and chalcogenide systems suitable for lithium intercalation reactions; characterization of their composition and structure; study of the chemical and electrochemical intercalation behaviour of these and other previously known materials; detailed evaluation of the performance of electrochemical test cells that combine intercalation electrodes by determining structural, thermodynamic and kinetic parameters affecting the intercalation process; modelling the experimental results and theoretical calculations to propose an electronic mechanism for the intercalation phenomena, and the study of the potential applicability of prototype cells with possible industrial interest. The latter objective is extensible to the design and determination of the performance of test cells for possible application in commercial batteries and the optimization of performance by combining the most adequate component materials in standard battery assemblies.
The group characterised the structures of the materials they studied as well as completing detailed thermodynamic and kinetic studies on the proposed battery materials. They considered the fundamental mechanisms involved in the movement of the lithium ions and tested the potential applicability for commercial battery prototypes in four case studies of rocking chair batteries. Although a final product, ready-for-market was not obtained, this was a basic research project and it now requires a partner from industry to continue the work. The high risk of any fundamental research project not solving the problem must always be weighed against the benefits of the potential application. In this case, the benefits of lighter, cleaner, longer lasting batteries are great.
Lithium batteries with positive intercalation electrodes offer several advantages due to their low weights and high energy densities. However, the use of lithium metal anodes in rechargeable batteries is restricted due to safety reasons, as dendritic lithium growth during charge leads to internal short circuits after 20-30 cycles, which may have explosive results. In order to avoid this problem, several first generation rocking chair batteries were proposed from 1982 to 1989, in which the anodic material was a lithium inserted oxide or chalcogenide system.
From 1990, a second generation of rocking-chair cells is being developed by different researchers in Japan, USA and Canada by using carbon (coke) as an anode material that inserts lithium at a low voltage during the charge of the cell. The Project intends an innovative approach to the study of rechargeable batteries at the European level, by examining different possibilities of combination of previously known and new inorganic materials - oxide and chalcogenide systems - that allow lithium insertion reactions and that are compatible in the constitution of rocking chair type cells with or without carbon anode. Basic research on the electrochemistry of these systems is of interest for a transfer to public or private industries directly concerned with the development of high performance energy storage devices. Related applications include the use of renewable energies for rural electricity or miniaturized power sources for electronics. Moreover, the substitution of other more contaminant systems such as lead or cadmium batteries by lighter units with higher capacities has relevant economic and environmental benefits.
Funding SchemeCSC - Cost-sharing contracts