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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.

The University of Delaware (UD) with their project partners will develop a new class of hydroxide exchange membranes (HEMs) for use in electrochemical devices such as fuel cells. Hydroxide exchange membrane fuel cells (HEMFC), in contrast to PEM fuel cells, can use catalysts based on low-cost metals as well as inexpensive membranes and bipolar plates. However, a low-cost HEM that simultaneously possesses adequate ion conductivity, chemical stability, and mechanical robustness does not yet exist.

Pennsylvania State University (Penn State) will develop a process for cold-sintering of ceramic ion conductors below 200°C to achieve a commercially viable process for integration into batteries. Compared to liquid electrolytes, ceramics and ceramic composites exhibit various advantages, such as lower flammability, and larger electrochemical and thermal stability. One challenge with traditional ceramics is the propagation of lithium dendrites, branchlike metal fibers that short-circuit battery cells.

3M will develop a new anion exchange membrane (AEM) technology with widespread applications in fuel cells, electrolyzers, and flow batteries. Unlike many proton exchange membrane (PEM) applications, the team’s AEM will operate in an alkaline environment, which means lower-cost electrodes can be used. The team plans to engineer a membrane that simultaneously meets key goals for resistance, mechanical and chemical stability, and cost. They will do this by focusing on simple, hydroxide-stable polymers, such as polyethylene, and stable cations, such as tetraalkylammonium and imidazolium groups.

The University of California, San Diego (UC San Diego), in partnership with Liox Power and the University of Maryland, will develop a self-forming, high temperature solid-state lithium battery that solves the critical cost and performance problems impeding commercialization of solid-state batteries for electric vehicles. The battery will possess a very long life due to a chemical mechanism that repairs cycling damage automatically. This self-healing electrolyte will also limit the growth of dendrites.

United Technologies Research Center (UTRC) will develop a redox flow battery system that combines next-generation reactants with an inexpensive and highly selective membrane. This SMART-FBS project addresses the two highest cost components in redox flow battery systems: reactants and membranes. The team plans to develop these two components simultaneously using core materials that will work in tandem. Polymer membranes will be developed that include benzimidazole or pyridine structures; ionic conductivity will come from the membrane’s structure that allows acid to be imbibed into the polymer.

Iowa State University (ISU) will develop new lithium-ion-conducting glassy solid electrolytes to address the shortcomings of present-day lithium batteries. The electrolytes will have high ionic conductivities and excellent mechanical, thermal, chemical, and electrochemical properties. Because glasses lack grain boundaries, they will also be impermeable to lithium dendrites, branchlike metal fibers that can short-circuit battery cells. These glassy solid electrolytes can enhance the safety, performance, manufacturability, and cost of lithium batteries.

24M Technologies will lead a team to develop low cost, durable, enhanced separators/solid state electrolytes to build batteries using a lithium metal anode. Using a polymer/solid electrolyte ceramic blend, 24M will be able to make a protective layer that will help eliminate side reactions that have previously contributed to performance degradation and provide a robust mechanical barrier to branchlike metal fibers called dendrites. Unimpeded, dendrites can grow to span the space between the negative and positive electrodes, causing a short-circuit.

American Manufacturing, in collaboration with the University of Colorado at Boulder, will develop a flash sintering system to manufacture solid lithium-conducting electrolytes with high ionic conductivity. Conventional sintering is the process of compacting and forming a solid mass by heat and/or pressure without melting it to the point of changing it to a liquid, similar to pressing a snowball together from loose snow. In conventional sintering a friable ceramic “bisque” is heated for several hours at very high temperatures until it becomes dense and strong.

Oak Ridge National Laboratory (ORNL) will develop glassy Li-ion conductors that are electrochemically and mechanically stable against lithium metal and can be integrated into full battery cells. Metallic lithium anodes could significantly improve the energy density of batteries versus today’s state-of-the-art lithium ion cells. ORNL has chosen glass as a solid barrier because the lack of grain boundaries in glass mitigates the growth of branchlike metal fibers called dendrites, which short-circuit battery cells.