EUROLIS · Advanced European lithium sulphur cells for automotive applications

Li-ion batteries become a reality in the future vehicles, although they do not fulfil completely the demands of consumers. In this respect batteries with higher energy density are required. Lithium technology utilizing sulphur as a cathode is one of the optimal choices since it offers the possibility of achieving high-energy, long-life storage batteries with a potential low price. At present, the practical use is faced with two major problems: (i) a low intrinsic conductivity of sulphur and polysulphides and (ii) loss of active materials due to solubility of the intermediate products in the commonly used electrolytes. The low intrinsic conductivity can be overcome using improved electronic wiring. The occurrence of soluble polysulphides is reflected as a loss of the active material during the cycling and additionally soluble polysulphides are responsible for overcharging problem which lowers the energy efficiency. With an aim to have stable capacity retention with a good cycling efficiency it is important to find a suitable electrochemical environment for the lithium – sulphur batteries. Possible approaches are using polysulphide reservoirs with modified surfaces in the highly mesoporous conductive matrix. Proposed system with high surface area should enable weak adsorption of polysulphides intermediates allowing reversible desorption. This way a full utilization of the active material without significant losses can be obtained. In order to understand the influence of surface area and surface modification, including interactions between electrolyte and sulphur based cathode composite we need to have a reliable characterization techniques. In this respect different electrochemical, spectroscopic and physical characterization (in-situ or ex-situ) techniques can provide us valuable information’s about the possible mechanism which can be used in planning of substrates for sulphur in the Li-S batteries.