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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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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Structure and Interface Design Enable Stable Li-Rich Cathode

Li-rich layered-oxide cathodes have the highest theoretical energy density among all the intercalated cathodes, which have attracted intense interests for high energy Li-ion batteries. However, O3-structured layered-oxide cathodes suffer from a low initial Coulombic efficiency (CE), severe voltage fade, and poor cycling stability because of the continuous oxygen release, structural rearrangements due to irreversible transition-metal migration, and serious side reactions between the delithiated cathode and electrolyte. In this work, we report that these challenges are migrated by using a stable O2-structured Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 (O2-LR-NCM) and all-fluorinated electrolyte. The O2-LR-NCM can restrict the transition metals migrating into the Li layer and the in situ formed fluorinated cathode electrolyte interphase (CEI) on the surface of the O2-LR-NCM from the decomposition of all-fluorinated electrolyte during initial cycles effectively restrains the structure transition, suppresses the O2 release, and thereby safeguards the transition metal redox couples, enabling a highly reversible and stable oxygen redox reaction. O2-LR-NCM in all fluorinated electrolytes achieves a high initial CE of 99.82 % and cycling CE of and cycling CE of >99.9%, high reversible capacity of 278 mAh/g, and high capacity retention of 83.3% after 100 cycles. The synergic design of electrolyte and cathode structure represents a promising direction to stabilize high-energy cathodes.

25 ENERGY STORAGE↗
NASA NTRS1989

Advanced high-temperature batteries

The promise of very high specific energy and power was not yet achieved for practical battery systems. Some recent approaches are discussed for new approaches to achieving high performance for lithium/DeS2 cells and sodium/metal chloride cells. The main problems for the development of successful LiAl/FeS2 cells were the instability of the FeS2 electrode, which has resulted in rapidly declining capacity, the lack of an internal mechanism for accommodating overcharge of a cell, thus requiring the use of external charge control on each individual cell, and the lack of a suitable current collector for the positive electrode other than expensive molybdenum sheet material. Much progress was made in solving the first two problems. Reduction of the operating temperatures to 400 C by a change in electrolyte composition has increased the expected life to 1000 cycles. Also, a lithium shuttle mechanism was demonstrated for selected electrode compositions that permits sufficient overcharge tolerance to adjust for the normally expected cell-to-cell deviation in coulombic efficiency. Sodium/sulfur batteries and sodium/metal chloride batteries have demonstrated good reliability and long cycle life. For applications where very high power is desired, new electrolyte coinfigurations would be required. Design work was carried out for the sodium/metal chloride battery that demonstrates the feasibility of achieving high specific energy and high power for large battery cells having thin-walled high-surface area electrolytes.

Nelson, Paul A.↗
NASA NTRS2004

Very High Efficiency, Miniaturized, Long-Lived Alpha Particle Power Source Using Diamond Devices for Extreme Space Environments

A power source that converts a-particle energy into electricity by coulomb collision in doped diamond films is described. Alpha particle decay from curium-244 creates electron-hole pairs by free- ing electrons and holes inside the crystal lattice in N- and P-doped diamond films. Ohmic contacts provide electrical connection to an electronic device. Due to the built-in electric field at the rectifying junction across the hT- and P-doped diamond films, the free electrons are constrained to traveling in generally one direction. This one direction then supplies electrons in a manner similar to that of a battery. The radioactive curium layer may be disposed on diamond films for even distribution of a-particle radiation. The resulting power source may be mounted on a diamond substrate that serves to insulate structures below the diamond substrate from a-particle emission. Additional insulation or isolation may be provided in order to prevent damage from a-particle collision. N-doped silicon may be used instead of N-doped diamond.

Elizabeth A Kolawa↗
DOE OSTI2022

Multinode Multi-GPU Two-Electron Integrals: Code Generation Using the Regent Language

The computation of two-electron repulsion integrals (ERIs) is often the most expensive step of integral-direct self-consistent field methods. Formally it scales as O(N 4 ), where N is the number of Gaussian basis functions used to represent the molecular wave function. In practice, this scaling can be reduced to O(N 2 ) or less by neglecting small integrals with screening methods. The contributions of the ERIs to the Fock matrix are of Coulomb (J) and exchange (K) type and require separate algorithms to compute matrix elements efficiently. We previously implemented highly efficient GPU-accelerated J-matrix and K-matrix algorithms in the electronic structure code TeraChem. Although these implementations supported the use of multiple GPUs on a node, they did not support the use of multiple nodes. This presents a key bottleneck to cutting-edge ab initio simulations of large systems, e.g., excited state dynamics of photoactive proteins. We present our implementation of multinode multi-GPU J- and K-matrix algorithms in TeraChem using the Regent programming language. Regent directly supports distributed computation in a task-based model and can generate code for a variety of architectures, including NVIDIA GPUs. We demonstrate multinode scaling up to 45 GPUs (3 nodes) and benchmark against hand-coded TeraChem integral code. Finally, we also outline our metaprogrammed Regent implementation, which enables flexible code generation for integrals of different angular momenta.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Design of High-Voltage Stable Hybrid Electrolyte with an Ultrahigh Li Transference Number

Considering the high energy consumption during processing, and the low compliance and adhesion of ceramic electrolytes, the integration of polymer into ceramic electrolytes provides a way to mitigate the interfacial issues. However, the severe ion concentration gradient, low ionic conductivity, and instability toward Li metal and high-voltage cathodes become the major concerns in applying hybrid electrolytes. In this work, we report a single-ionconducting hybrid electrolyte (SIE-LLZO) with 64 wt % Li 7 La 3 Zr 2 O 12 (LLZO) particles embedded in a fluoroboron-centered Li-conductive polymer framework (LiBFSIE). The SIE-LLZO electrolyte exhibited a high Li transference number of 0.94 and electrochemical stability up to 5.6 V vs Li/Li + . Promising averaged Coulombic efficiencies of 99.97% and 99.91% were achieved in cells with LiNi 0.8 Co 0.15 Al 0.05 O 2 and LiNi 0.6 Mn 0.2 Co 0.2 O2 cathodes for 400 and 200 cycles, respectively. Finally, the Li-conducting pathway in the hybrid electrolyte was further investigated by a 6 Li-to- 7 Li isotope replacement method, indicating that Li transport mainly relies on the LLZO and interface between LiBFSIE and LLZO.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Li-substituted layered spinel cathode materials for sodium ion batteries

Systems, methods, and compositions are disclosed for a Li-substituted layered-tunneled O3/spinel Na(NixFeyMnz)O2 cathode material, Na0.87Li0.25Ni0.4Fe0.2Mn0.4O2+∂ (LS-NFM) for enhanced sodium ion storage and cycling stability. The LS-NFM electrode is prepared by adjusting the stoichiometric ratio of the Na ion over the sum of Li and transition metal ions below 1. The Rietveld refinement of XRD data indicates that the cathode is composed of 94% layered and 6% spinel components. When cycled at a high current density of 100 mA g−1, LS-NFM cathode exhibited a first-cycle Coulombic efficiency of 88% and reversible discharge capacity of 107 mAh g−1 after 50 cycles with the capacity retention of 95%.

Xiong, Hui↗
DOE OSTI2022

Electrochemically induced amorphous-to-rock-salt phase transformation in niobium oxide electrode for Li-ion batteries

Intercalation-type metal oxides are promising negative electrode materials for safe rechargeable lithium-ion batteries due to the reduced risk of Li plating at low voltages. Nevertheless, their lower energy and power density along with cycling instability remain bottlenecks for their implementation, especially for fast-charging applications. Here, we report a nanostructured rock-salt Nb 2 O 5 electrode formed through an amorphous-to-crystalline transformation during repeated electrochemical cycling with Li + . This electrode can reversibly cycle three lithiums per Nb 2 O 5 , corresponding to a capacity of 269 mAh g –1 at 20 mA g –1 , and retains a capacity of 191 mAh g –1 at a high rate of 1 A g –1 . Further, it exhibits superb cycling stability with a capacity of 225 mAh g –1 at 200 mA g –1 for 400 cycles, and a Coulombic efficiency of 99.93%. We attribute the enhanced performance to the cubic rock-salt framework, which promotes low-energy migration paths. Our work suggests that inducing crystallization of amorphous nanomaterials through electrochemical cycling is a promising avenue for creating unconventional high-performance metal oxide electrode materials.

25 ENERGY STORAGE↗
DOE OSTI2022

Low-Oxidized Siloxene Nanosheets with High Capacity, Capacity Retention, and Rate Capability in Lithium-Based Batteries

The mechanical degradation experienced by Si electrodes during Li (de)alloying reactions can potentially be mitigated by using Si-based materials with layered 2D geometries. Such materials are expected to exhibit favorable mechanical properties and be capable of buffering the volume change associated with (de)lithitation. In this work, 2D siloxene nanosheets are synthesized using a facile topotactic reaction followed by ultrasonication as an exfoliation step. Here, detailed structural and chemical characterization via electron microscopy, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy is conducted, revealing a low-oxidized siloxene nanosheet material with only 15% surface Si-oxide. The obtained siloxene nanosheets are tested as Li-ion negative electrodes in lithium-based electrochemical cells. The cells exhibit high rate capability with a capacity of 935 mAh g –1 at 3200 mA g –1 and ≈99.5% coulombic efficiency. The inclusion of fluoroethylene carbonate (FEC) in the electrolyte improves capacity retention over 200 cycles from 13% to 77% at 1000 mA g –1 . This behavior is attributed to the FEC decomposition forming a solid electrolyte interphase (SEI) with higher ion conductivity and robust LiF/Li x PO y F z content, as characterized via XPS Raman spectroscopy.

25 ENERGY STORAGE↗
DOE OSTI2023

Accelerated Short Circuiting in Anode-Free Solid-State Batteries Driven by Local Lithium Depletion

“Anode-free” solid-state batteries (SSBs), which have no anode active material, can exhibit extremely high energy density (≈1500 Wh L -1 ). However, there is a lack of understanding of the lithium plating/stripping mechanisms at initially lithium-free solid-state electrolyte (SSE) interfaces because excess lithium metal is often used. Here, it is demonstrated that commercially relevant quantities of lithium (>5 mAh cm -2 ) can be reliably plated at moderate current densities (1 mA cm -2 ) using the sulfide SSE Li 6 PS 5 Cl. Investigations of lithium plating/stripping mechanisms, in conjunction with cryo-ocused ion beam (FIB) imaging, synchrotron tomography, and phase-field modeling, reveal that the cycling stability of these cells is fundamentally limited by the nonuniform presence of lithium during stripping. Local lithium depletion causes isolated lithium regions toward the end of stripping, decreasing electrochemically active area and resulting in high local current densities and void formation. This accelerates subsequent filament growth and short circuiting compared to lithium-excess cells. Despite this degradation mode, here it is shown that anode-free cells exhibit comparable Coulombic efficiency to lithium-excess cells, and improved resistance to short circuiting is achieved by avoiding local lithium depletion through retention of thicker lithium at the interface. These new insights provide a foundation for engineering future high-energy anode-free SSBs.

25 ENERGY STORAGE↗
DOE OSTI2023

Localized High–Concentration Electrolytes with Low–Cost Diluents Compatible with Both Cobalt–Free LiNiO 2 Cathode and Lithium–Metal Anode

High-nickel layered oxide cathodes and lithium-metal anode are promising candidates for next-generation battery systems due to their high energy density. Nevertheless, the instability of the electrode–electrolyte interphase is hindering their practical application. Localized high-concentration electrolytes (LHCEs) present a promising solution for achieving uniform lithium deposition and a stable cathode–electrolyte interphase. However, the limited choice of diluents and their high cost are restricting their implementation. Four novel cost-effective diluents and their performance with highly reactive LiNiO 2 cathode and Li-metal anode are reported here. The results show that all the LHCE cells exhibit a Coulombic efficiency of >99.38% in Li | Cu cells and a capacity retention of >85% in Li | LiNiO 2 cells after 250 cycles. Advanced characterizations unveil that the stable cell operation is due to well-tuned electrode–electrolyte interphases and Li deposition morphology. In addition, online electrochemical mass spectroscopy and differential scanning calorimetry reveal that the gas generation and heat-release are greatly reduced with the LHCEs presented. Altogether, the study provides new insights into the role of diluents in LHCEs and offers valuable guidance for further optimization of LHCEs for high energy density lithium-metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

1000 Wh L−1 lithium-ion batteries enabled by crosslink-shrunk tough carbon encapsulated silicon microparticle anodes

Abstract Microparticulate silicon (Si), normally shelled with carbons, features higher tap density and less interfacial side reactions compared to its nanosized counterpart, showing great potential to be applied as high-energy lithium-ion battery anodes. However, localized high stress generated during fabrication and particularly, under operating, could induce cracking of carbon shells and release pulverized nanoparticles, significantly deteriorating its electrochemical performance. Here we design a strong yet ductile carbon cage from an easily processing capillary shrinkage of graphene hydrogel followed by precise tailoring of inner voids. Such a structure, analog to the stable structure of plant cells, presents ‘imperfection-tolerance’ to volume variation of irregular Si microparticles, maintaining the electrode integrity over 1000 cycles with Coulombic efficiency over 99.5%. This design enables the use of a dense and thick (3 mAh cm–2) microparticulate Si anode with an ultra-high volumetric energy density of 1048 Wh L–1 achieved at pouch full-cell level coupled with a LiNi0.8Co0.1Mn0.1O2 cathode.

25 ENERGY STORAGE↗
DOE OSTI2021

Rechargeable Alkaline Zinc/Copper Oxide Batteries

Resurrecting a battery chemistry thought to be only primary, we demonstrate the first example of a rechargeable alkaline zinc/copper oxide battery. With the incorporation of a Bi 2 O 3 additive to stabilize the copper oxide-based conversion cathode, Zn/(CuO–Bi 2 O 3 ) cells are capable of cycling over 100 times at >124 W h/L, with capacities from 674 mA h/g (cycle 1) to 362 mA h/g (cycle 150). The crucial role of Bi 2 O 3 in facilitating the electrochemical reversibility of Cu 2 O, Cu(OH) 2 , and Cu o was supported by scanning and transmission electrochemical microscopy, cyclic voltammetry, and rotating ring-disc electrode voltammetry and monitored via operando energy-dispersive X-ray diffraction measurements. Bismuth was identified as serving two roles, decreasing the cell resistance and promoting Cu(I) and Cu(II) reduction. Additionally, to mitigate the capacity losses of long-term cycling CuO cells, we demonstrate two limited depth of discharge (DOD) strategies. First, a 30% DOD (202 mA h/g) retains 99.9% capacity over 250 cycles. Second, the modification of the CuO cathode by the inclusion of additional Cu metal enables performance at very high areal capacities of ~40 mA h/cm 2 and unprecedented energy densities of ~260 W h/L, with near 100% Coulombic efficiency. This work revitalizes a historically primary battery chemistry and opens opportunity to future works in developing copper-based conversion cathode chemistries for the realization of low-cost, safe, and energy-dense secondary batteries.

25 ENERGY STORAGE↗
DOE OSTI2026

Manipulating Na/TM Ratio‐Driven Structural Heterogeneity of O3‐NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Cathode for High‐Voltage Sodium‐Ion Batteries

The stability of O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 under high-voltage cycling is dictated by how synthesis encodes lattice strain and redox heterogeneity. Here, in this study, the role of Na:TM stoichiometry is systematically resolved by tuning the NaOH:precursor ratio during solid-state synthesis. The stoichiometric condition (Na:TM = 1.00) yields minimized microstrain, enabling uniform O3–P3 phase evolution and homogeneous multi-metal redox with preserved octahedral symmetry. In contrast, Na-excess compositions inherit disordered intermediates and heterogeneous distortion fields that trigger abrupt multiphase transitions and promote localized charge redistribution. In situ XRD captures the divergence in phase-transition pathways, TXM resolves particle-level redox heterogeneity, and XANES corroborates a stronger and more reversible Fe redox contribution at stoichiometry, shifting to diminished Fe participation and spatially inhomogeneous redox at higher Na content. These results establish Na:TM stoichiometry as a critical synthesis parameter controlling both structural coherence and redox stability. Electrochemically, the stoichiometric composition exhibits smooth voltage profiles with minimal polarization growth and retains nearly 80% of its initial capacity after 100 cycles even at an extended 4.2 V cutoff, whereas Na-excess compositions show significantly reduced initial coulombic efficiency and rapid voltage fade. Precise stoichiometric tuning provides a scalable route to defect-suppressed O3 frameworks, enabling structurally resilient, high-voltage sodium-layered cathodes.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Solvent Dynamics in Gel Polymer Electrolytes for Lithium–Sulfur Batteries

Li−sulfur (Li−S) batteries are promising as the next-generation energy storage technology but face challenges due to sluggish sulfur redox reaction (SRR) kinetics and a sulfur shuttling effect. While many studies have explored polycaprolactone (PCL)-based gel polymer electrolytes (GPEs) to address these issues, the influence of solvent properties, including dielectric constant (ϵ) and donor and acceptor numbers (DN and AN), remain unexplored despite their critical impact on performance and full-scale implementation. This study systematically compares three distinct electrolytes, dimethoxyethane (DME), dimethyl sulfoxide (DMSO), and tetraethylene glycol dimethyl ether (TEGDME)-paired with PCL, to correlate the varied solvent properties and their effects on the physical properties of the GPE, in terms of Li + transport and solvation, and polysulfide’s confinement. Among them, the DME-based GPE, with an intermediate DN, exhibited the lowest crystallinity (2.31%), highest ionic conductivity (7.49 mS/cm), and high Li + transference number (0.77). As a result, it achieved a specific capacity of 795 mAh/g sulfur and an average Coulombic efficiency of 97.5% after 120 cycles at C/5, outperforming its competitors. Operando Raman and UV−vis spectroscopy confirmed that PCL effectively confines long-chain polysulfides within its network, mitigating the shuttle effect and facilitating reversible polysulfide conversion. These findings demonstrate that GPEs with moderate DN values and balanced ϵ significantly enhance stability, extend cycle life, and improve rate performance for Li−S batteries. This work provides valuable insights into the design of advanced electrolyte systems for practical energy storage applications.

25 ENERGY STORAGE↗
DOE OSTI2026

An Organic Carboxylate Host for Stable Sodium Metal Batteries

Sodium metal batteries (SMBs) hold great promise for the development of high-energy, sustainable energy storage solutions, but their practical deployment is hampered by unstable solid electrolyte interphases, uncontrollable sodium dendrite growth, and low Coulombic efficiency (CE) during repeated Na plating/stripping cycles. To address these challenges, we introduce an organic interlayer, containing perylenetetracarboxylic dianhydride sodium salt (Na4PT), on the surface of Cu current collector. This interlayer forms a sodiophilic organic interphase that lowers the nucleation barriers for sodium deposition and guides the formation of the interphase through polar carbonyl/carboxylate sites and a π-conjugated organic framework. A dendrite-free sodium metal anode is achieved using Na4PT coated Cu current collector. Under capacity-limited Na plating/stripping, Na||Na4PT@Cu half-cells deliver reversible capacities of 500 and 1,000 mAh g−1 at 0.1 and 1 A g−1 for 500 cycles with average CE above 99%. Post-cycling scanning electron microscopy and X-ray photoelectron spectroscopy measurements confirm that Na4PT@Cu promotes compact and uniform Na deposits and supports the formation of a stable interphase with reduced parasitic decomposition, directly correlating interfacial chemistry/morphology with high plating/stripping reversibility. These results highlight organic carboxylate coating as a practical interface engineering strategy for dendrite-free SMBs.

Chen, Chengxiang [University of Miami]↗
DOE OSTI2023

In Situ Ion‐Exchange Metathesis Induced Conformal LiF Surface Films on Cathode (NMC811) as a Cathode Electrolyte Interphase

High-capacity cathodes (LiNi 0.8 Mn 0.1 Co 0.1 O 2 , NMC811) are promising for vehicle electrification because of their high gravimetric energy density. However, their electrochemical performance still relies upon the stability of the cathode electrolyte interphase (CEI). A highly reactive cathode interface leads to parasitic side reactions with electrolytes, resulting in accelerated capacity fading. Well-developed LiF and LiF-like inorganic compounds are believed to be good CEI components for stabilizing such reactive electrode interfaces. However, it is challenging to form an optimal surface sub-nanolayer of LiF on the cathode surfaces because of the complexity of the electrochemical reaction during battery cycling. Herein, the formation of a conformal LiF layer on the NMC811 electrode surface via an in situ ion-exchange metathesis process is reported, demonstrating a promising electrochemical performance because of a LiF-stabilized CEI. In situ generated LiF-coated NMC811 electrodes exhibit ≈97% capacity retention up to 100 cycles at a 0.3 C rate with average coulombic efficiency of ≈99.9% and ≈80% capacity retention up to 200 cycles at a 1 C rate with average coulombic efficiency of >99.6%. This finding may pave the way for reengineering the CEI to enhance the electrochemical performances and cycling stability of the high-capacity cathodes.

25 ENERGY STORAGE↗
DOE OSTI2023

All-temperature zinc batteries with high-entropy aqueous electrolyte

Electrification of transportation and rising demand for grid energy storage continue to build momentum around batteries across the globe. However, the supply chain of Li-ion batteries is exposed to the increasing challenges of resourcing essential and scarce materials. Therefore, incentives to develop more sustainable battery chemistries are growing. Here, in this paper, we show an aqueous ZnCl 2 electrolyte with introduced LiCl as supporting salt. Once the electrolyte is optimized to Li 2 ZnCl 4 ∙9H 2 O, the assembled Zn–air battery can sustain stable cycling over the course of 800 hours at a current density of 0.4 mA cm -2 between -60 °C and +80 °C, with 100% Coulombic efficiency for Zn stripping/plating. Even at -60 °C, >80% of room-temperature power density can be retained. Advanced characterization and theoretical calculations reveal a high-entropy solvation structure that is responsible for the excellent performance. The strong acidity allows ZnCl 2 to accept donated Cl - ions to form ZnCl 4 2- anions, while water molecules remain within the free solvent network at low salt concentration or coordinate with Li ions. Our work suggests an effective strategy for the rational design of electrolytes that could enable next-generation Zn batteries.

25 ENERGY STORAGE↗