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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS2007

Multiple internal seal right micro-electro-mechanical system vacuum package

A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum package that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

Hayworth, Ken J.↗

NASA NTRS2008

Multiple internal seal ring micro-electro-mechanical system vacuum packaging method

A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum packaging method that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

Hayworth, Ken J.↗

NASA NTRS1977

Electrostatic analysis of charge-coupled structures

Package of three computer programs performs two-dimensional electrostatic analysis to determine efficiency of charge transfer. One program can be used to analyze three-electrode charge-coupled device input/output gates, and other two programs can be used to analyze two-phase structures containing two or four electrodes with periodic boundary conditions.

Gassaway, J. D.↗

NASA NTRS1992

Surface-Acoustic-Wave Piezoelectric Microbalance

Improved piezoelectric microbalances developed for use in measuring masses of volcanic, aerosol, and other small particles suspended in air. Sensitive microbalance used to analyze airborne particles in real time in environments as diverse as clean rooms or upper atmosphere. Surface-acoustic-wave resonator includes input and output sets of interdigitated electrodes and two passive conductive patterns acting as reflectors. Mechanical energy travels both ways out from middle and reflected back toward middle. Microbalance and associated circuitry fit in small package. Circuit draws only 80 mA at 5 V. Sensitivity more than 400 times that of bulk piezoelectric microbalance.

Chuan, Raymond L.↗

NASA NTRSDate not supplied

Solid-state Architecture Batteries for Enhanced Rechargeability and Safety (SABERS) for Extended Deep Space Applications

Extended duration deep space missions as well as permanent space habitats face numerous technical challenges, key among them is energy generation and energy storage. There are considerable monetary and technical barriers to the generation of power in space. Therefore, it is important to store and be able to access power in an efficient and safe manner over a large number of cycles. Energy storage and in particular, batteries, are vital to the operation of next-generation extraterrestrial shuttles, rovers, habitats and extravehicular activity (EVA) space suits. The performance metrics for extended duration space missions are at least 2 times greater than those set for terrestrial applications such as electric automobiles. Furthermore, safety is essential for operation of space missions particularly involving astronauts such as shuttles, habitats and EVA space suits. Preliminary systems level analysis has indicated that there are five key properties which must be optimized for successful implementation of battery systems. Those five key criteria are: safety, energy density, power, packaging design and scalability. Current state-of-the-art (SOA) lithium-ion batteries can meet or exceed the requirements for certain space applications in the areas of power and scalability, yet are insufficient in the key performance criteria of energy, safety and packaging design. The SABERS concept proposes a battery that meets all five key performance criteria through development of a solid-state architecture battery utilizing high capacity sulfur-selenium cathode and lithium metal anode. The combination of sulfur and selenium offers a balanced energy-to-power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This hybrid cathode will be developed by implementing NASA patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. A solid-state electrolyte will be used as a safe, non-flammable replacement to the highly flammable liquid organic electrolytes currently used in SOA lithium-ion batteries. This solid-state lithium-sulfur/selenium cell will be designed into a serial stacking configuration to enable dense packaging of the battery cells. The serial stacking configuration is termed a bipolar stack, which has the advantages of reducing overall cell weight, simplifying the interfaced connections for the cell, and minimizing the cooling requirements for the cell. Lastly, optimization of battery components will occur through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a fully solid-state battery with operational temperatures up to 150 °C which provides the required energy density, discharge rates, and inherent safety to meet the strict space mission performance criteria. In particular, the wide operational temperature window is required for the large temperature ranges which are experienced across a broad range of potential space missions. This presentation will show initial results that demonstrate the SABERS team has developed a composite carbon-sulfur cathode which exceeds 1100 Wh/kg at a discharge rate of 0.4C, and 804 Wh/kg at a discharge rate of 1C. Additionally, this presentation will show the SABERS team multiscale computational modeling approach and has produced a novel particle dynamics method called Solid Electrolyte Sphere Approximation Model (SESAM). SESAM is on the 1-10 µm scale and provides electromechanical and grain interactions for predictive design guidelines for the experimental team to follow.

Urban Air Mobility (UAM) Vehicles↗

NASA NTRSDate not supplied

Solid-state Architecture Batteries for Enhanced Rechargeability and Safety for Electric Aircraft

All electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The most challenging of these technical barriers to overcome is developing an energy storage system capable of meeting the rigorous aerospace safety and performance criteria. The performance metrics for eVTOL craft are at least 2 times greater than those of electric automobiles. Furthermore, safety is essential for operation of commercial electric aerovehicles. Preliminary systems level analysis has indicated that there are five key properties which must be optimized for successful implementation of battery systems. Those five key criteria are: safety, energy density, power, packaging design and scalability. Current state-of-the-art (SOA) lithium-ion batteries meet or exceed the requirements for electric aviation in the areas of power and scalability, yet are insufficient in the key performance criteria of energy, safety and packaging design. The SABERS concept proposes a battery that meets all five key performance criteria through development of a solid-state architecture battery utilizing high energy density and power density sulfur-selenium cathode with a lithium metal anode. The combination of sulfur and selenium offers a balanced energy-to-power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This cathode will be developed by implementing NASA patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. A solid-state electrolyte will be used as a safe, non-flammable replacement to the highly flammable liquid organic electrolytes currently used in SOA lithium-ion batteries. This solid-state lithium-sulfur-selenium cell will be designed into a serial stacking configuration to enable dense packaging of the battery cells. The serial stacking configuration is termed a bipolar stack, which has the advantages of reducing overall cell weight, reducing the amount of interfaced connections for the cell, and minimizing the cooling requirements for the cell. Lastly, optimization of battery components will occur through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a fully solid-state battery with operational temperatures from 0 °C to 150 °C which provides the required energy density, discharge rates, and inherent safety to meet the strict aerospace performance criteria. This presentation will show initial results that demonstrate the SABERS Team has developed a composite carbon-sulfur cathode which exceeds 1100 Wh/kg at a discharge rate of 0.4C, and 804 Wh/kg at a discharge rate of 1C. Additionally, this presentation will show the SABERS Team multiscale computational modeling approach and has produced a novel particle dynamics method called Solid Electrolyte Sphere Approximation Model (SESAM). SESAM is on the 1-10 µm scale and provides electromechanical and grain interactions for predictive design guidelines for the experimental team to follow.

Urban Air Mobility (UAM) Vehicles↗

NASA NTRSDate not supplied

Computational Modeling Development of Solid-state Architecture Batteries for Enhanced Rechargeability and Safety for Electric Aircraft

Urban Air Mobility (UAM) Vehicles↗

NASA NTRS1977

Preliminary investigation of a sealed, remotely activated silver-zinc battery

Methods necessary to provide a remotely activated, silver zinc battery capable of an extended activated stand while in a sealed condition were investigated. These requirements were to be accomplished in a battery package demonstrating an energy density of at least 35 watt hours per pound. Several methods of gas suppression were considered in view of the primary nature of this unit and utilized the electroplated dendritic zinc electrode. Amalgamation of the electrode provided the greatest suppression of gas at the zinc electrode. The approach to extending the activated stand capability of the remotely activated battery was through evaluation of three basic methods of remote, multi-cell activation; 1) the electrolyte manifold, 2) the gas manifold and 3) the individual cell. All three methods of activation can be incorporated into units which will meet the minimum energy density requirement.

Wheat, C. G.↗

NASA NTRS2007

Compact Packaging of Photonic Millimeter-Wave Receiver

A carrier structure made from a single silicon substrate is the basis of a compact, lightweight, relatively inexpensive package that holds the main optical/electronic coupling components of a photonic millimeter-wave receiver based on a lithium niobate resonator disk. The design of the package is simple and provides for precise relative placement of optical components, eliminating the need for complex, bulky positioning mechanisms like those commonly used to align optical components to optimize focus and coupling. Although a prototype of the package was fabricated as a discrete unit, the design is amenable to integration of the package into a larger photonic and/or electronic receiver system. The components (see figure) include a lithium niobate optical resonator disk of 5-mm diameter and .200- m thickness, positioned adjacent to a millimeter- wave resonator electrode. Other components include input and output coupling prisms and input and output optical fibers tipped with ball lenses for focusing and collimation, respectively. Laser light is introduced via the input optical fiber and focused into the input coupling prism. The input coupling prism is positioned near (but not in contact with) the resonator disk so that by means of evanescent-wave coupling, the input laser light in the prism gives rise to laser light propagating circumferentially in guided modes in the resonator disk. Similarly, a portion of the circumferentially propagating optical power is extracted from the disk by evanescent-wave coupling from the disk to the output coupling prism, from whence the light passes through the collimating ball lens into the output optical fiber. The lens-tipped optical fibers must be positioned at a specified focal distance from the prisms. The optical fibers and the prisms must be correctly positioned relative to the resonator disk and must be oriented to obtain the angle of incidence (55 in the prototype) required for evanescent-wave coupling of light into and out of the desired guided modes in the resonator disk. To satisfy all these requirements, precise alignment features are formed in the silicon substrate by use of a conventional wet-etching process. These features include a 5-mm-diameter, 50- m-deep cavity that holds the disk; two trapezoidal-cross-section recesses for the prisms; and two grooves that hold the optical fibers at the correct positions and angles relative to the prisms and disk. The fiber grooves contain abrupt tapers, near the prisms, that serve as hard stops for positioning the lenses at the focal distance from the prisms. There are also two grooves for prismadjusting rods. The design provides a little slack in the prism recesses for adjusting the positions of the prisms by means of these rods to optimize the optical coupling.

Nguyen, Hung↗

NASA NTRS2012

Dielectric Performance of High Purity HTCC Alumina at High Temperatures - A Comparison Study with Other Polycrystalline Alumina

A very high purity (99.99+) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this co-fired material. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96 polycrystalline alumina (96 Al2O3), where 96 alumina was used as the benchmark. A prototype packaging system based on regular 96 alumina with Au thick-film metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500C. In order to evaluate this new HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96 alumina and a LTCC alumina from room temperature to 550C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96 alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

High temperature↗

NASA NTRS2014

Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - a Comparison Study with Other Polycrystalline Alumina

A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thickfilm metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500 C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550 C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

Electronic packaging↗

NASA NTRS1983

Advanced nickel hydrogen cell configuration study

An evaluation of the current nickel hydrogen cell design is presented. The IPV, or the Individual Pressure Vessel, is the state of the art right now. The present design, 3 1/2 inch cell, has a current limit of 50 ampere-hours. The nickel hydrogen cell design is the state of the art. Its size is 3 1/2 inches which limits it to 50 hours. The probable limits of that are probably 160 amphere IPV cell remaining in the passive cooling mode. The IPV stacks is a parallel connection of electrodes. Positive electrodes are connected with leads to the top portion of the stack and negative electrodes are connected with leads and pulled down to the bottom. So it is a combination connection of paralleling series electrostacking--parallel inside each individual stack, and series connected from one stack to the next. It offers, in the analysis, improvements in packaging, cost, energy density, and specific energy.

Adler, E.↗

NASA NTRS2011

Carbon Nanotube-Based Structural Health Monitoring Sensors

Carbon nanotube (CNT)-based sensors for structural health monitoring (SHM) can be embedded in structures of all geometries to monitor conditions both inside and at the surface of the structure to continuously sense changes. These CNTs can be manipulated into specific orientations to create small, powerful, and flexible sensors. One of the sensors is a highly flexible sensor for crack growth detection and strain field mapping that features a very dense and highly ordered array of single-walled CNTs. CNT structural health sensors can be mass-produced, are inexpensive, can be packaged in small sizes (0.5 micron(sup 2)), require less power than electronic or piezoelectric transducers, and produce less waste heat per square centimeter than electronic or piezoelectric transducers. Chemically functionalized lithographic patterns are used to deposit and align the CNTs onto metallic electrodes. This method consistently produces aligned CNTs in the defined locations. Using photo- and electron-beam lithography, simple Cr/Au thin-film circuits are patterned onto oxidized silicon substrates. The samples are then re-patterned with a CNT-attracting, self-assembled monolayer of 3-aminopropyltriethoxysilane (APTES) to delineate the desired CNT locations between electrodes. During the deposition of the solution-suspended single- wall CNTs, the application of an electric field to the metallic contacts causes alignment of the CNTs along the field direction. This innovation is a prime candidate for smart skin technologies with applications ranging from military, to aerospace, to private industry.

Wincheski, Russell↗

NASA NTRS2020

Solid-state Architecture Batteries for Enhanced Rechargeability and Safety (SABERS)

All-electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The most challenging of these technical barriers to overcome is developing an energy storage system capable of meeting the rigorous aerospace safety and performance criteria. The performance metrics for eVTOL craft, such as specific energy and cycle life, are at least 2 times greater than those of electric automobiles. Furthermore, safety is essential for operation of commercial electric aerovehicles. Preliminary systems level analysis studies have indicated that there are five key properties which must be optimized for successful implementation of battery systems. Those five key criteria are safety, energy density, power, packaging design and scalability. Current state-of-the-art (SOA) lithium-ion batteries meet or exceed the requirements for electric aviation in the areas of power and scalability, yet are insufficient in the key performance criteria of energy, safety and packaging design. The SABERS concept proposes a battery that meets all five key performance criteria through the development of a solid-state architecture cell design utilizing high energy density and power density sulfur-selenium cathode with a lithium metal anode. Data will be presented demonstrating high performing sulfur - selenium cathode that offers a balanced energy to power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This cathode is being developed by implementing NASA patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. Novel processing methods allow developing solid-state electrolyte that is a safe, non-flammable replacement to the highly flammable liquid organic electrolytes currently used in SOA lithium-ion batteries. The all solid-state lithium-sulfur-selenium cell design enables the implementation of a bipolar stack configuration, which has the advantages of reducing overall cell weight, reducing the amount of interfaced connections for the cell, and minimizing cooling requirements for the battery. In particular, the solid-state design allows for a serial stacking configuration to enable dense packaging of the cells within the bipolar stack. Lastly, optimization of battery components occurs through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a solid-state battery with operational temperatures from 0 °C to 150 °C which provides the required energy density, discharge rate, and inherent safety to meet strict aerospace performance criteria.

solid state batteries↗

NASA NTRS2002

Radial Field Piezoelectric Diaphragms

A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

Bryant, R. G.↗

NASA NTRSDate not supplied

Solid-state Architecture Batteries for Enhanced Rechargeability and Safety (SABERS) for Electric Aircraft

All-electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The primary barrier to overcome is developing an energy storage system capable of meeting the rigorous aerospace safety and performance criteria. The performance metrics for eVTOL vehicles are at least two times greater than those of electric ground vehicles. Furthermore, inherently non-flammable batteries are essential for safe operation of commercial electric aerovehicles. The SABERS concept proposes a battery that meets the key performance criteria through development of a solid-state architecture battery utilizing high-capacity sulfur-selenium cathode and lithium metal anode. The combination of sulfur and selenium offers a balanced energy-to-power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This hybrid cathode will be developed by implementing NASA patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. A solid-state electrolyte will be used as a safe, non-flammable replacement to the highly flammable liquid organic electrolytes currently used in SOA lithium-ion batteries. This solid-state lithium-sulfur/selenium cell will be designed into a serial stacking configuration to enable dense packaging of the battery cells. The serial stacking configuration is termed a bipolar stack, which has the advantages of reducing overall cell weight, simplifying the interfaced connections for the cell, and minimizing the cooling requirements. Lastly, optimization of battery components will occur through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a fully solid-state battery with operational temperatures up to 150 °C which provides the required energy density, discharge rates, and inherent safety to meet the strict aerospace mission performance criteria. This presentation will demonstrate a feasible path for solid-state cells that possess a specific energy of greater than 400 Wh/kg to enable electric aircraft.

Urban Air Mobility (UAM) Vehicles↗

NASA NTRSDate not supplied

Solid-state Architecture Batteries for Enhanced Rechargeability and Safety (SABERS) Beyond Li-Ion: Technology to Enable Sustainable Electric Aviation

All-electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The primary barrier to overcome is developing an energy storage system capable of meeting the rigorous aerospace safety and performance criteria. The performance metrics for eVTOL vehicles are at least two times greater than those of electric ground vehicles. Furthermore, inherently non-flammable batteries are essential for safe operation of commercial electric aerovehicles. The SABERS concept proposes a battery that meets the key performance criteria through development of a solid-state architecture battery utilizing high-capacity sulfur-selenium cathode and lithium metal anode. The combination of sulfur and selenium offers a balanced energy-to-power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This hybrid cathode will be developed by implementing NASA patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. A solid-state electrolyte will be used as a safe, non-flammable replacement to the highly flammable liquid organic electrolytes currently used in SOA lithium-ion batteries. This solid-state lithium-sulfur/selenium cell will be designed into a serial stacking configuration to enable dense packaging of the battery cells. The serial stacking configuration is termed a bipolar stack, which has the advantages of reducing overall cell weight, simplifying the interfaced connections for the cell, and minimizing the cooling requirements. Lastly, optimization of battery components will occur through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a fully solid-state battery with operational temperatures up to 150 °C which provides the required energy density, discharge rates, and inherent safety to meet the strict aerospace mission performance criteria. This presentation will demonstrate a feasible path for solid-state cells that possess a specific energy of greater than 400 Wh/kg to enable electric aircraft.

Urban Air Mobility (UAM) Vehicles↗

NASA NTRS2023

Solid-State Architecture Batteries for Enhanced Rechargeability and Safety (SABERS): Advanced Battery Technology for Sustainable Aviation

All-electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The primary barrier to overcome is developing an energy storage system capable of meeting the rigorous aerospace safety and performance criteria. The performance metrics for eVTOL vehicles are at least two times greater than those of electric ground vehicles. Furthermore, inherently non-flammable batteries are essential for safe operation of commercial electric aerovehicles. The SABERS concept proposes a battery that meets the key performance criteria through development of a solid-state architecture battery utilizing high-capacity sulfur-selenium cathode and lithium metal anode. The combination of sulfur and selenium offers a balanced energy-to-power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This hybrid cathode will be developed by implementing NASA patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. A solid-state electrolyte will be used as a safe, non-flammable replacement to the highly flammable liquid organic electrolytes currently used in SOA lithium-ion batteries. This solid-state lithium-sulfur/selenium cell will be designed into a serial stacking configuration to enable dense packaging of the battery cells. The serial stacking configuration is termed a bipolar stack, which has the advantages of reducing overall cell weight, simplifying the interfaced connections for the cell, and minimizing the cooling requirements. Lastly, optimization of battery components will occur through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a fully solid-state battery with operational temperatures up to 150 °C which provides the required energy density, discharge rates, and inherent safety to meet the strict aerospace mission performance criteria. This presentation will demonstrate a feasible path for solid-state cells that possess a specific energy of greater than 400 Wh/kg to enable electric aircraft. The presentation will also explore novel materials and computational models used to achieve all solid-state cells that operate safely at very high temperatures and specific energies. The cells can withstand damage while operating without an increase in temperature or spontaneous ignition.

Urban Air Mobility (UAM) Vehicles↗