(531g) Advanced Halogenated Electrolytes for Improved Performance, Safety, and Cycle Life of High Energy Lithium-Ion Batteries

High capacity cathodes are necessary for the development of future high energy density lithium-ion batteries, although challenges to safe charge transfer between these cathodes and the electrolytes need to be surmounted to create a cost effective battery solution. Stability of the solid-electrolyte interface layer is important for improving cycle life, necessary for most battery applications, and promoting safer operations, to prevent dangerous exothermic reactions that can cause thermal runaway. The Army is looking at these technologies as a way to increase the energy density of soldier worn batteries, which account for > 40 pounds of the ~130 pounds a soldier carries when deployed. In this project we utilized a in house developed chlorinated manganese spinel due to a > 200 mAh/g capacity and 5 V cell operation. Common high voltage electrolytes employ fluorinated carbonates that seem to cause a parasitic interaction between the chlorinated cathode materials and the electrolyte. Determination of the degradation effects will help inspire future electrolytes for chlorinated spinel materials for future battery technologies and create a > 400 Wh/Kg cell with stable cycle life. SEM, EDS, and XRD were utilized to evaluate the degradation of the cathode surface with repeated cycling. Additional, efforts are targeted in creating rapid charge transfer at the electrode / electrolyte surface with non-flammable electrolytes to further enhance the safety characteristics of these cells. Future high energy density batteries with stable charge transfer are necessary for the developing battery industry, especially electronic vehicles, and will help reduce the battery weight burden of soldiers while deployed on mission.