Next-Generation Li-Ion Batteries: High performance through 5V Stable and Highly Conductive Inorganic Electrolyte

Conventional lithium-ion batteries utilizing organic electrolyte suffer severely from several drawbacks associated to the poor electrochemical stability at higher potentials, high volatility and flammability of electrolyte components as well as poor performance at lower temperatures. To overcome these issues we developed a novel purely inorganic electrolyte consisting of sulfur dioxide as a solvent and a proprietary conductive salt. [1,2] This electrolyte formulation shows superior stability towards potentials of up to 5V together with exceptional ionic conductivity exceeding organic electrolyte by up to an order of magnitude. Throughout this presentation we will discuss in detail the basic properties and electrochemical performance of our SO2-based electrolytes in comparison to state of the art organic electrolyte. Extensive research efforts of the last few years have led to a unique electrolyte system, which is capable to withstand electrolyte decomposition beyond a potential of 5V. The larger potential window allows for higher average discharge potentials and significantly increased capacities. For NMC, for instance, a capacity increase of 20% is possible, which not only enhances cell energy but may also reduce cost due to more efficient cathode utilization. 21700 cells manufactured with our pilot-scale manufacturing equipment already achieved energy densities as high as 310 Whkg-1 with ordinary NMC/graphite cell chemistry. Recently, we have shown that our cells not only may be cycled for hundreds of cycles at 4.6 V but also demonstrate exceptional charge/discharge characteristics at temperatures as low as -40 °C. Our cells also passed all tests associated to UN38.3 which paves the way towards commercial applications. Our technology may be understood as a drop in solution for large scale battery cell manufacturing. Only small modifications with regard to electrolyte handling and filling have to be made by maintaining all other cell manufacturing processes such as electrode coating and cell assembly. This together with the prospect of proven compatibility with future electrode materials such as LMR, LNMO, LFMP, Silicon or lithium metal makes our technology highly adaptable and future proof.