Anode-Electrolyte Interlayering in Solid-State Batteries via Dry-Processing

The first technique improves electrolyte densification, which is essential for ion conductivity and battery reliability overall. The process involves the use of a sintering aid (e.g., sulfur) to achieve denser and more stable electrolytes than are achievable through more common, high-temperature processes. Electrolytes that are denser and less porous have higher ion conductivity (thus better performance), longer cycle lives, and lower volatility. Aside from densification, this technique also significantly increased the base electrolyte's lithium wettability. The second innovation is a new cathode and electrolyte design using a mixed conducting material that can carry both ions and electrons, which simplifies the cathode’s composition by eliminating the need for separate ion and electron conductors. This catholyte is a composite that utilizes a mixed conducting material, replacing both the ion and electron conductors with a single material thus simplifying solid state cathode design from a 3-component to 2-component composite. The mixed material is composed of a metal chalcogenide, such as titanium disulfide (TiS2), which can act as a mixed conductor and contributes to energy storage. The addition of sulfur boosts energy capacity up to 33% compared to traditional cathode designs. Reducing single-conduction phases simplifies energy transport pathways and improves efficiency, making solid-state batteries easier to produce and safer to use. These two innovations work together to improve the state of the art, creating solid-state batteries with higher temperature tolerances and up to five times more energy capacity than current lithium-ion batteries. They stand together at a TRL 4 and are available for patent licensing individually or as part of the larger SABERS (LEW-TOPS-167) or SABERS 2.0 portfolio (LEW-TOPS-188).

Battery cells are sealed inside a strong, flexible pouch which is placed inside a lightweight pressure vessel filled with inert working fluid (e.g., argon gas, silicone oil) that applies a low pressure evenly around the pouch, ensuring uniform compression and eliminating directional stress on the cell. This case maintains constant pressure throughout the battery’s life cycle to ensure consistent contact between solid components, which optimizes performance and minimizes damage. The pressure necessary in this design is much lower than that in uniaxial systems, which allows for a less heavy packaging system. This lightweight design and improved technique may show particular relevance on large scales (e.g., aerospace, automotive), where onboard load weight and longevity are priorities. This isostatic battery case contributes to the SABERS 2.0 portfolio (LEW-TOPS-188), improving the state of the art for solid-state batteries. Currently at a TRL 4, the case is available to license independently or as part of the larger SABERS solid-state battery suite.

The SABERS innovators developed novel lithium-sulfur designs, including sulfur-selenium on graphene cathodes, and lightweight bipolar plate stacking and packaging designs. SABERS is unique in several aspects, in particular, it deploys graphene-based manufacturing processes for the cathode and bipolar plates, and it uses a solid-state electrolyte in place of the liquid electrolyte found in other lithium-sulfur battery designs. The team has achieved energy densities over 500 W-hr/kg, with ongoing development targeting further improvements. Coin cell and pouch prototype demonstrations have been successful and are ongoing. Major component technologies in SABERS include the following: • S/Se Cathode – Sulfur/Selenium on graphene scaffold (LEW-20228-1) • Solid Electrolyte – Solid-state electrolyte composites (LEW-20445-1) • Bipolar Stack – Graphene plates (LAR-20257-1) Robust computational models have been developed to support the battery materials design and are available to licensees to evaluate and optimize different materials combinations and performance targets. Further developments in catholyte formulations, anode interlayering, and packaging optimization are presented in SABERS 2.0 (LEW-TOPS-188). Individual technologies can be licensed from either suite, or entire portfolios can be licensed to support solid-state battery development programs.

The original SABERS portfolio established foundational materials and architecture for solid-state lithium-sulfur batteries through innovations in graphene-based cathodes, solid electrolytes, and bipolar plate designs. Building on this foundation, SABERS 2.0 addresses critical challenges that have limited the practical implementation and scalability of solid-state batteries: cathode efficiency and electrolyte performance, anode interface stability, and cell-level packaging optimization. The SABERS 2.0 portfolio comprises four complementary innovations that work together to improve solid-state battery performance and manufacturing viability. Major licensable technologies in the SABERS 2.0 portfolio include: • Mixed Conducting Cathodes and Dense Electrolytes (LEW-TOPS-186): Two complementary innovations in electrolyte densification and catholyte formulation that simplify manufacturing and improve energy capacity, ion conductivity, and battery reliability. • Solvent-Free Anode Interlayer (LAR-TOPS-405): A dry-processed interlayer that prevents dendrite formation, maintains stable interfaces, and enables cost-effective, environmentally friendly manufacturing. • Isostatically Pressurized Cell Case (LEW-TOPS-187): A lightweight pressure vessel system that provides uniform compression to solid-state cells, eliminating the need for heavy machinery while enhancing performance and longevity. These technologies may be licensed independently, as part of the SABERS 2.0 suite, or in custom combination with the technologies in the original SABERS suite (LEW-TOPS-167).

The Ram-Dent Thermal Runaway Triggering Device is capable of trig-gering mild short circuits that are similar to internal defects, and more extreme short circuits that are comparable to those initiated by an implanted internal short circuit device – all without having to modify the battery cell in any way. The device imparts a high velocity, low mass blunt impact onto a small surface area of a Li-ion battery cell can wall allowing a small hemispherical dent to form. This impact deforms and tears the internal separator of the battery cell, causing a short circuit, and induces thermal runaway. Several methods for initiating TR on demand currently exist, but they have characteristics and biases that make them more unfavorable for certain testing objectives. Heat-based insult in any form requires additional thermal energy to be applied to the battery cell, potentially distorting the signal-to-noise ratio in FTRC measurement, and increas-ing the severity of failure beyond what is intended. This methodology also requires time to heat the battery cell to critical temperature, and it potentially weakens the battery cell can wall causing abnormal kinetics and rupture. Mechanical insult methodologies, such as crush testing and nail penetration, have unique applications but rely on deformation of the battery cell itself which alters the flow characteristics of internal gases and the material integrity of the battery cell. This technology aims to solve these limitations by implementing a cost-effective method to create a natural short circuit failure in Li-ion batteries that does not alter nominal vent paths and energy yields, potentially yielding the most unbiased calorimeter tallies yet. The Ram-Dent Thermal Runaway Triggering Device is at a technology readiness level (TRL) 4 (component and/or breadboard validation in laboratory environment) and is now available for patent licensing. Please note that NASA does not manufacture products itself for commercial sale.