Sila Nanotechnologies

Demand for Lithium-ion (Li-ion) batteries has increased significantly as products such as smartphones, laptops, electric vehicles, and grid storage batteries rise in popularity. However, Li-ion batteries have numerous safety and performance limitations due to their flammable electrolyte and the charge storage density of their active materials, which are not easily overcome by incremental progress. New types of high-performance separators and electrodes built with solid-state ion conductors could simultaneously improve the energy density and safety of lithium ion batteries by removing the most flammable battery components, and also improving the driving range and durability of electric vehicles. Solid-state separators also open the door to the use of lithium metal as an active material, resulting in a significant increase in cell energy content, and the subject of research efforts for the past several decades. New battery technology that employs energy dense, thermally stable, and long-lasting materials will also be of interest for grid storage, particularly in dense, urban environments where the space occupied by storage systems is more of a concern.

Sila Nanotechnologies will develop solid-state ceramic lithium batteries with high energy density. Traditional methods using ceramic electrolytes significantly reduces a battery’s volumetric energy density because the materials are relatively bulky. Commercially produced separator membranes are also expensive and thick because of challenges in fabrication and handling of thinner, defect-free solid-state electrolyte membranes. In addition, such membranes are often air sensitive, have low ionic conductivity, and are susceptible to the growth of branchlike metal fibers called dendrites. Unimpeded, dendrites can grow to span the space between the negative and positive electrodes, causing short-circuiting. To overcome these limitations the team proposes a shift in solid-state battery technology: melt-infiltrating of a solid-state electrolyte at moderate temperatures into a porous separator-cathode stack. This reduces cell volume by nearly three times, while resulting in a corresponding increase in energy density and cost-reduction. The result is a product with low cost and high production yield, built on a process similar to conventional organic electrolyte-filling techniques. The equipment for this process will be very similar to what is currently used in Li-ion battery manufacturing, except that it will be slightly modified for operation at elevated temperatures of up to 250-400°C. The use of equipment similar to what is currently used by industry will reduce the risks of technology scale-up.

If successful, developments made under the IONICS program will increase the energy storage content for vehicle batteries by about 30% compared to today's Li-ion batteries and significantly reduce battery storage system costs.