Multilayered Superionic Conductive Conformal Solid Electrolyte for Lithium Metal/High Nickel Lithium Nickel Manganese Cobalt (NMC) Cells

The Department of Energy is leading efforts to develop advanced battery technologies for Electric Vehicles (EVs). Improving the performance and lowering the cost of batteries will help to further increase market penetration of EVs, consequently reducing our nation’s dependence on foreign oil. The current state-of-the-art in EV battery technology is Lithium Ion batteries (LIBs); however, LIBs would significantly benefit from higher specific energy densities (currently about 170~265 Wh/kg) and improved durability. Lighter and more durable batteries will increase the range of EVs and/or lower the total battery cost per vehicle. The electrode materials determine the specific energy of LIBs. An attractive and straightforward approach to increase the specific energy is to utilize new electrode materials that have larger capacities. Among all the future electrode material candidates, lithium metal is the most promising anode due to its large capacity and largest negative voltage. However, traditional liquid electrolytes can neither prevent Li dendrite formation nor are stable with respect to lithium metal for prolonged cycles. Replacement of the liquid electrolytes with solid electrolytes could be a viable solution for lithium metal anode systems. The proposed technology in this project is to develop a superionically conductive (conductivity > 10-3 S/cm at room temperature) solid polymer electrolyte that is suitable for Lithium Metal/High Nickel Lithium Nickel Manganese Cobalt (NMC) cells. The team will further develop a multilayered electrolyte system to allow the use of high nickel NMC cathodes which is crucial for high energy density LIBs. The lamination of two polymer electrolytes will provide both superionic conductivity and high cathode stability, allowing the utilization of the full capacity of the cathode. If successful, the resulting solid-state Li Metal/High Ni NMC cells will achieve gravimetric energy densities over 400 Wh/kg, which is 50% higher than the start-of-art lithium ion batteries. Such a high energy density certainly will be beneficial for EV applications. In addition, the solid-state cells have intrinsic safety advantages over liquid electrolyte based batteries, making them a safer choice for energy storage. Beyond the EV application, safe batteries with ultrahigh energy densities will attract attention of manufactures from consumer electronics industry.