Development of Lithium-Sulfur/Silicon Batteries (LiSSi) with high specific energy for automotive application

Purpose of the project LiSSi (VW AG, Wacker Chemie AG, TUM) is to develop a novel type of rechargeable battery with high specific energy of 450 Wh/kg at cell level and 300 Wh/kg at system level (vehicle traction battery). The system is based on the combination of a Li2S cathode and a Si anode. In contrast to state-of-the-art lithium-ion batteries this combination also provides higher intrinsic safety.

Nevertheless, the current lithium-sulfur batteries have some problems that prevent commercialization. This is the low number of cycles and the low current rates. The project includes material research on electrodes and electrolyte, tests of small half cells and the production of full cells of larger capacity (goal: 2.5 Ah). In addition, work will be undertaken in the field of battery modeling, so the heat balance of the Li2S/Si-technology and its influence can be modeled in order to derive optimal operating strategies. For prediction and modeling of the aging behavior extensive experiments are planned.

The goal of the project is to provide a more environment-friendly mobility by lithium-sulfur and silicon based technology. In respect to the recent challenges a big production is not expected before 2020, so that the application of the project results initially concentrates on patent protection and publication. The transfer of this technology into other markets such as stationary energy storage is always kept in view.