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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Sound velocities of iron-nickel (Fe90Ni10) alloy up to 8 GPa and 773 K: The effect of nickel on the elastic properties of bcc-iron at high P-T

Sound velocities of iron and iron-based alloys at high pressure and high temperature are crucial for understanding the composition and structure of Earth’s and other telluric planetary cores. In this study, we performed ultrasonic interferometric measurements of both compressional (ν P ) and shear (ν S ) velocities on a polycrystalline body-centered-cubic (bcc)-Fe 90 Ni 10 up to 8 GPa and 773 K. The elastic moduli and their pressure and temperature derivatives are derived from least-square fits to third-order finite strain equations, yielding K S0 = 154.2(8) GPa, G 0 = 73.2(2) GPa, K' S0 = 4.6(2), G' 0 = 1.5(1), ∂K S /∂T = –0.028(1) GPa/K, and ∂G/∂T = –0.023(1) GPa/K. Furthermore, a comparison with literature data on bcc-Fe suggests that nickel not only decreases both P and S wave velocities but also weakens the temperature effects on the elastic moduli of Fe-Ni alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2021

SURFACE FINISHING AND ELECTROLESS NICKEL PLATING OF ADDITIVELY MANUFACTURED (AM) METAL COMPONENTS

This study investigates the application of electroless nickel deposition on additively manufactured stainless steel samples. Current additive manufacturing (AM) technologies produce metal components with a rough surface. Rough surfaces generally exhibit fatigue characteristics, increasing the probability of initiating a crack or fracture to the printed part. For this reason, the direct use of as-produced parts in a finished product cannot be actualized, which presents a challenge. Post-processing of the AM parts is therefore required to smoothen the surface. This study analyzes chempolish (CP) and electropolish (EP) surface finishing techniques for post-processing AM stainless steel components CP has a great advantage in creating uniform, smooth surfaces regardless of size or part geometry EP creates an extremely smooth surface, which reduces the surface roughness to the sub-micrometer level. In this study, we also investigate nickel deposition on EP, CP, and as-built AM components using electroless nickel solutions. Electroless nickel plating is a method of alloy treatment designed to increase manufactured component's hardness and surface resistance to the unrelenting environment. The electroless nickel plating process is more straightforward than its counterpart electroplating.. We use low-phosphorus (2-5% P), medium-phosphorus (6-9% P), and high-phosphorus (10-13% P). These Ni deposition experiments were optimized using the L9 Taguchi design of experiments (TDOE), which compromises the prosperous content in the solution, surface finish, plane of the geometry, and bath temperature. The pre-and post-processed surface of the AM parts was characterized by KEYENCE Digital MicroscopeVHX-7000 and Phenom XL Desktop SEM. The experimental results show that electroless nickel deposition produces uniform Ni coating on the additively manufactured components up to 20 μm per hour. Mechanical properties of as-built and Ni coated AM samples were analyzed by applying a standard 10 N scratch test. Nickel coated AM samples were up to two times scratch resistant compared to the as-built samples. This study suggests electroless nickel plating is a robust viable option for surface hardening and finishing AM components for various applications and operating conditions.

Keywords: additive manufacturing, fatigue, chempol↗
DOE OSTI2021

Hierarchical nickel valence gradient stabilizes high-nickel content layered cathode materials

High-nickel content cathode materials offer high energy density. However, the structural and surface instability may cause poor capacity retention and thermal stability of them. To circumvent this problem, nickel concentration-gradient materials have been developed to enhance high-nickel content cathode materials’ thermal and cycling stability. Even though promising, the fundamental mechanism of the nickel concentration gradient’s stabilization effect remains elusive because it is inseparable from nickel’s valence gradient effect. To isolate nickel’s valence gradient effect and understand its fundamental stabilization mechanism, we design and synthesize a LiNi 0.8 Mn 0.1 Co 0.1 O 2 material that is compositionally uniform and has a hierarchical valence gradient. The nickel valence gradient material shows superior cycling and thermal stability than the conventional one. The result suggests creating an oxidation state gradient that hides the more capacitive but less stable Ni 3+ away from the secondary particle surfaces is a viable principle towards the optimization of high-nickel content cathode materials.

25 ENERGY STORAGE↗
DOE OSTI2020

High energy/power density nickel oxide/hydroxide materials and nickel cobalt oxide/hydroxide materials and production thereof

According to one embodiment, a method includes forming a nickel oxide/hydroxide active film onto a substrate from a solution including a nickelous salt and an electrolyte, where the nickel oxide/hydroxide active film has a physical characteristic of maintaining greater than about 80% charge over greater than 500 charge/discharge cycles, and wherein the nickel oxide/hydroxide active film has a physical characteristic of storing electrons at greater than about 0.5 electron per nickel atom.

25 ENERGY STORAGE↗
DOE OSTI2020

Impact of Residual Lithium on the Adoption of High-Nickel Layered Oxide Cathodes for Lithium-Ion Batteries

High-nickel layered oxide cathodes are becoming appealing for lithium-ion batteries employed in portable electronics and electric vehicles because of their higher energy density, low or no cobalt content, and ability to be manufactured with existing infrastructure. However, high-nickel layered oxides are plagued by the formation of residual lithium species, such as LiOH and Li 2 CO 3 , on the surface, which are detrimental to the manufacturing process and performance. Despite the problems residual lithium causes for the industry, academia mainly focuses on the safety risks and electrochemical impacts of residual lithium. In this Perspective, we examine the residual lithium problem through a lens of its impact on cathode slurry instability and large-scale manufacturing of high-nickel layered oxides. Additionally, methods of measuring residual lithium are discussed from the perspective of their accuracy as well as practicality in the manufacturing process. Furthermore, we hope that this Perspective would encourage the academic endeavor to consider the practical obstacles caused by residual lithium on the industrialization of high-nickel layered oxides and their mitigation, while attempting to improve their electrochemical performance and safety through doping, surface modifications, or other approaches.

25 ENERGY STORAGE↗
DOE OSTI2021

Characterization and High Temperature Electrical Properties of Brazed Joints of La0.8Sr0.2CrO3 with Nickel and Nickel Alloys

This study investigates the high-temperature electrical properties and microstructural characteristics of brazed joints combining La₀.₈Sr₀.₂CrO₃ (LSC) with nickel and nickel-based alloys. Using nickel-based filler metals (NB LM and NB 130), the joints were tested in controlled atmospheres (95% N₂ and 5% H₂). Electrical resistivity was analyzed across a range of temperatures (25–727°C), and contact resistance was evaluated using a composite model. Results indicate that joint resistance decreases with increasing temperature, with optimal brazing achieved at 1160°C. Diffusion processes involving Si, Ni, O, and Sr were identified, with silicon oxide formation contributing to joint bonding.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2022

Effect of Composition and Local Environment on CO 2 Adsorption on Nickel and Magnesium Oxide Solid Solutions

CO 2 adsorption energies on the (100) surfaces of a nickel oxide doped with Mg, magnesium oxide doped with Ni, and their 50:50 solid solution were calculated using density functional theory. The composition and atomic arrangement of the adsorption site was varied to understand how the local environment affects CO 2 adsorption and the basicity of the surfaces at the atomic level. The dispersive and electronic contributions to the adsorption energies were quantified, and the results indicate that the variation of the adsorption energy with adsorption site configuration and metal composition is dominated by electronic interactions. Interestingly, for magnesium oxide doped with nickel, a single substitution can create stronger CO 2 binding sites, which implies stronger basic sites, even though nickel oxide is less basic than magnesium oxide. The effect of double substitution at the binding site can be reasonably approximated by summing the effects of single substitutions. Furthermore, this work provides guidance for the preparation of metal oxides with tailored Lewis basicity.

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

In–Depth Analysis of the Degradation Mechanisms of High–Nickel, Low/No–Cobalt Layered Oxide Cathodes for Lithium–Ion Batteries

A rational compositional design of high-nickel, cobalt-free layered oxide materials for high-energy and low-cost lithium-ion batteries would be expected to further propel the widespread adoption of electric vehicles (EVs), yet a composition with satisfactory electrochemical properties has yet to emerge. The previous work has demonstrated a promising LiNi 0.883 Mn 0.056 Al 0.061 O 2 (NMA-89) composition that outperformed high-nickel, cobalt-containing analogs in cycling stability and maintained a comparable rate performance and thermal stability. Herein, the capacity fading mechanism of NMA-89 in a pouch full cell with a 4.2 V cutoff is compared to that of its cobalt-containing analogs. The results reveal that particle cracking in LiNi 0.89 Mn 0.055 Co 0.055 O 2 (NMC-89) and LiNi 0.883 Co 0.053 Al 0.064 O 2 (NCA-89) leads to a loss of active material and an increase in surface area, thereby exacerbating structural and surface instabilities, accelerating impedance and polarization growth, and ultimately reducing their capacity retentions. LiNi 0.89 Mn 0.044 Co 0.042 Al 0.013 Mg 0.011 O 2 (NMCAM-89) and NMA-89 experience subdued surface reactions and maintain spherical particle structures, both of which are conducive to their capacity retentions during long-term cycling. Furthermore, this investigation offers insights into how specific transition-metal ions dictate the electrochemical stability of high-Ni layered oxide cathode materials, highlights the benefit of Mn-Al combination in NMA-89, and presents potential strategies to further enhance the performance of this novel class of cathode materials.

degradation mechanisms↗
DOE OSTI2021

A Cobalt– and Manganese–Free High–Nickel Layered Oxide Cathode for Long–Life, Safer Lithium–Ion Batteries

High-nickel LiNi 1–x–y Mn x Co y O 2 and LiNi 1–x–y Co x Al y O 2 cathodes are receiving growing attention due to the burgeoning demands on high-energy-density lithium-ion batteries. The presence of both cobalt and manganese in them, however, triggers multiple issues, including high cost, high toxicity, rapid surface deterioration, and severe transition-metal dissolution. Herein, a Co- and Mn-free ultrahigh-nickel LiNi 0.93 Al 0.05 Ti 0.01 Mg 0.01 O 2 (NATM) cathode that exhibits 82% capacity retention over 800 deep cycles in full cells, outperforming two representative high-Ni cathodes LiNi 0.94 Co 0.06 O 2 (NC, 52%) and LiNi 0.90 Mn 0.05 Co 0.05 O 2 (NMC, 60%) is presented. It is demonstrated that a titanium-enriched surface along with aluminum and magnesium as the stabilizing ions in NATM not only ameliorates unwanted side reactions with the electrolyte and structural disintegrity, but also mitigates transition-metal dissolution and active lithium loss on the graphite anode. As a result, the graphite anode paired with NATM displays an ultrathin (≈8 nm), monolayer anode-electrolyte interphase architecture after extensive cycling. Furthermore, NATM displays considerably enhanced thermal stability with an elevated exothermic temperature (213 °C for NATM vs 180 and 190 °C for NC and NMC, respectively) and remarkably reduced heat release. This work sheds light on rational compositional design to adopt ultrahigh-Ni cathodes in lithium-based batteries with low cost, long service life, and improved thermal stability.

25 ENERGY STORAGE↗
DOE OSTI2021

Unusual Role of Point Defects in Perovskite Nickelate Electrocatalysts

Low-cost transition-metal oxide is regarded as a promising electrocatalyst family for an oxygen evolution reaction (OER). The classic design principle for an oxide electrocatalyst believes that point defect engineering, such as oxygen vacancies (VO .. ) or heteroatom doping, offers the opportunities to manipulate the electronic structure of material toward optimal OER activity. Oppositely, in this work, we discover a counterintuitive phenomenon that both VO .. and an aliovalent dopant (i.e., proton (H + )) in perovskite nickelate (i.e., NdNiO 3 (NNO)) have a considerably detrimental effect on intrinsic OER performance. Detailed characterizations unveil that the introduction of these point defects leads to a decrease in the oxidative state of Ni and weakens Ni-O orbital hybridization, which triggers the local electron-electron correlation and a more insulating state. Evidenced by first-principles calculation using the density functional theory (DFT) method, the OER on nickelate electrocatalysts follows the lattice oxygen mechanism (LOM). The incorporation of point defect increases the energy barrier of transformation from OO*(V O ) to OH*(V O ) intermediates, which is regarded as the rate-determining step (RDS). Furthermore, this work offers a new and significant perspective of the role that lattice defects play in the OER process.

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

Unveiling the Stabilities of Nickel–Based Layered Oxide Cathodes at an Identical Degree of Delithiation in Lithium–Based Batteries

Bulk, surface, and interfacial instabilities that impact the cycle and thermal performances are the major challenges with high-energy-density LiNi 1–x–y Mn x Co y O 2 (NMC) cathodes with high nickel contents. It is generally believed that the instabilities and performance losses become exponentially aggravated as the nickel content increases. Disparate from this prevailing belief, it is herein demonstrated that NMC cathodes with higher Ni contents may imply better overall stability than “lower-Ni” cathodes under an identical degree of delithiation (charging) conditions. With two representative cathodes, LiNi 0.8 Mn 0.1 Co 0.1 O 2 and LiNiO 2 , a systematic investigation into their stabilities with control of the degree of delithiation is presented. Electrochemical tests indicate that LiNiO 2 displays better cyclability than LiNi 0.8 Mn 0.1 Co 0.1 O 2 at the same delithiation state. Comprehensive structural and interphase investigations unveil that the inferior cyclability of LiNi 0.8 Mn 0.1 Co 0.1 O 2 predominantly results from aggravated parasitic reactions, and the interphase stability may be more critical than lattice stability in dictating cyclability. Also, LiNiO 2 delivers similar or better thermal behavior than LiNi 0.8 Mn 0.1 Co 0.1 O 2 . Finally, the findings demonstrate a strong correlation of the stability of NMC cathodes to the degree of delithiation state rather than the Ni content itself, highlighting the importance of reassessing the true implications of Ni content and structural and interphasial tuning on the stabilities of NMC cathodes.

25 ENERGY STORAGE↗
DOE OSTI2026

The Influence of Mesoscale Particle Structure on the Electrode Degradation and Resultant Electrochemistry of Lithium Ion Cells With Nickel Rich Lithium Nickel Manganese Cobalt Oxide Positive Electrodes

Nickel-rich lithium nickel manganese cobalt oxide, NMC (LiNi x Mn y Co z O 2 ), materials are desirable positive electrodes in lithium ion batteries, providing high capacity and energy density. The mesoscale structure of NMC materials is commonly a polycrystalline aggregate, providing opportunity for short lithium ion transport distance of the small primary particles, yet facile material handling due to the larger secondary particles. On (de)lithiation the NMC unit cell changes volume, where the anisotropic strain can result in secondary particle fracture. This secondary particle fracture process during cycling has been associated with several degradation modes of NMC materials in LIBs. In this work, a milling process was determined whereby the secondary particles could be pre-fractured with retention of the parent primary particle crystallographic structure, crystallite size, and morphology, providing the ability to unambiguously determine the influence of NMC secondary particle size and mesostructure on resultant functional behavior. The bulk and interfacial properties and electrochemistry of as-received commercially obtained polycrystal NMC811 (LiNi 0.8 Mn 0.1 Co 0.1 O 2 , PC NMC) and its milled MPC NMC counterpart were compared. The smaller secondary particle size, higher surface area MPC NMC was found to result in 1) greater cathode tortuosity, 2) reduced surface Ni on the cycled MPC cathodes consistent with surface reconstruction, and 3) increased Ni deposition on the anodes from cathode-anode crosstalk. These factors manifested in unfavorable electrochemical behavior of MPC with lower functional capacity at both 1C and C/10 rates and higher impedance over extended moderate voltage (dis)charge cycling.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Gas Generation in Lithium Cells with High-Nickel Cathodes and Localized High-Concentration Electrolytes

High-nickel layered-oxide cathodes (LiNi x Mn y Co 1-x-y O 2 , x ≥ 0.8) exhibit high capacities, but also experience rapid capacity fade during cycling, and are susceptible to heat generation and gas release. Advanced electrolytes, such as localized high-concentration electrolytes (LHCE), substantially stabilize the cathode during cycling and have lower flammability than conventional electrolytes, but gas generation with these electrolytes is yet to be assessed. We demonstrate here that gas generation from a high-nickel cathode in an LHCE is half as much as in a conventional electrolyte at 4.4 V. The gas generation in LHCE is further reduced at 4.3 V, but the LHCE generates a similar amount of gas as the conventional electrolyte at 4.6 V. Neither electrolyte can prevent gas generation after cycling; cathodes after 200 cycles generate similar amounts of gas as pristine cathodes during high-voltage hold. Finally, it is shown that in both electrolytes, oxygen from the cathode lattice plays a critical role in gas generation.

25 ENERGY STORAGE↗