Advanced Electrolytes for Safe, High Voltage, High Energy Cells

The specific objective of this STTR is to develop a high energy dense, safe, rechargeable Li battery by replacing the conventional flammable carbonate-based electrolyte with a solid state electrolyte and/or ionic liquid.  This proposal focuses on developing a > 350 Wh/kg cell with an average discharge voltage of >4.6 V and retaining > 80% capacity over 100 cycles, using a room temperature ionic liquid (RTIL) as electrolyte.  To achieve high energy density, a Li metal anode will be coupled to high voltage lithium nickel manganese oxide (LNMO) [1] cathode.  SEI formation on Li is eliminated with Sisom’s Engineered Particle® coating. Formation of a stable SEI formation on high voltage cathodes has been demonstrated with both conventional and RTIL electrolytes.    The team of Lithium Battery Engineering (LBE), Ohio State University (OSU)  and Sisom Thin Films, LLC brings together all the necessary technologies to achieve the goals of this STTR. The underlying experience includes: a working 4.2 V High Power Carbon/RTIL/NMC111 cell a working 4.2 V High Power silicon /RTIL/NMC111 cell a working RTIL for lithium metal cells. a working (flammable) electrolyte  for a 4.8 V carbon//LMNO cell a new RTIL that has been shown effective in lithium metal – NMC811 high voltage cells Sisom Thin Films’s patented protective coating for lithium metal Ohio State’s expertise in RTILs and electrochemical and characterization methods for probing SEI formation on anodes and cathodes In SBIR–A153-101 LBE worked with high voltage RTILs and developed a non-flammable silicon/NMC cell that could CHARGE and discharge at 40% of room temperature capacity at -30 oC.    In SBIR A18-079, LBE developed a successful new electrolyte for improved performance of lithium metal cells.  LBE has also developed a working 4.8 V carbon//LNMO cell. Sisom has patented a Li metal anode stabilized with a porous engineered particle film which has been demonstrated to eliminate drawbacks of Li metal anodes including dendrite growth. This technology won Sisom the 2020 LG/Hyundai EV and Battery Challenge. Ohio State University has extensive experience in solid state electrolytes and RTILs. Prof Co’s research focus is in understanding and developing analytical tools and electrochemical methods to probe SEI formation. The OSU lab is multidisciplinary, combining electrochemical, analytical, materials and physical chemistry techniques and will resolve/reconcile the electrochemical reactions between RTILs and LNMO. Our approach is to combine the collective expertise of the team to develop and deliver ten safe, high energy, lithium metal anode with ceramic coating/RTIL electrolyte/LNMO cathode cells.       [1]  Lithium Nickel Manganese Oxide is the only cathode we know with a 4.8V discharge profile.