Search NASA⌕ Search

SEARCH · Search NASA

Results for “nickel electrodes”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Impact of Nickel Ions on the Oxygen Reduction Reaction Kinetics of Pt and on Oxygen Diffusion through Ionomer Thin Films

The effects of dissolved nickel on the oxygen reduction reaction (ORR) kinetics and oxygen transport properties of perfluorosulfonic acid (PFSA) thin films were investigated using rotating disk electrode (RDE) measurements of ORR on a PFSA-coated platinum electrode. The electrochemical characterization in 0.1 M perchloric acid (HClO 4 ) with and without added Ni 2+ quantitatively measured the impact of ionic interactions between the Ni 2+ cations and sulfonate (SO 3 - ) anions on oxygen transport through the PFSA thin film. Cyclic voltammetry (CV) curves in deaerated electrolyte showed that Ni 2+ cations diffusing through the PFSA thin film interact with the Pt surface altering the hydrogen underpotential deposition and stripping processes and decreasing ORR kinetics. The RDE limiting current results point to reduced permeability of oxygen through PFSA-Ni 2+ compared to PFSA-H + . Furthermore, the results indicate that transition metals leached from Pt alloy catalyst may be detrimental not only to the intrinsic ORR kinetics of the PEFC cathode catalyst through loss of the ORR-enhancing transition metal, but may also inhibit the diffusion of oxygen to the catalytic sites and poison the ORR.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
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

Efficient Hydrogen Delivery for Microbial Electrosynthesis via 3D-Printed Cathodes

The efficient delivery of electrochemically in situ produced H 2 can be a key advantage of microbial electrosynthesis over traditional gas fermentation. However, the technical details of how to supply large amounts of electric current per volume in a biocompatible manner remain unresolved. Here, we explored for the first time the flexibility of complex 3D-printed custom electrodes to fine tune H 2 delivery during microbial electrosynthesis. Using a model system for H 2 -mediated electromethanogenesis comprised of 3D fabricated carbon aerogel cathodes plated with nickel-molybdenum and Methanococcus maripaludis, we showed that novel 3D-printed cathodes facilitated sustained and efficient electromethanogenesis from electricity and CO 2 at an unprecedented volumetric production rate of 2.2 L CH4 /L catholyte /day and at a coulombic efficiency of 99%. Importantly, our experiments revealed that the efficiency of this process strongly depends on the current density. At identical total current supplied, larger surface area cathodes enabled higher methane production and minimized escape of H 2 . Specifically, low current density (<1 mA/cm 2 ) enabled by high surface area cathodes was found to be critical for fast start-up times of the microbial culture, stable steady state performance, and high coulombic efficiencies. Our data demonstrate that 3D-printing of electrodes presents a promising design tool to mitigate effects of bubble formation and local pH gradients within the boundary layer and, thus, resolve key critical limitations for in situ electron delivery in microbial electrosynthesis.

03 NATURAL GAS↗
DOE OSTI2021

Electrolyte Regulating toward Stabilization of Cobalt-Free Ultrahigh-Nickel Layered Oxide Cathode in Lithium-Ion Batteries

Cobalt (Co)-free ultrahigh-nickel (Ni) layered oxides exhibit a double-edged competitive advantages in reducing the cathode cost and boosting the energy density, promising the sustainable development of batteries for electric vehicles. However, the increased Ni content, resultantly more highly oxidative Ni 4+ , potentially induces severe capacity fading due to the aggravated side reactions, limiting the practical applications. Here, we evaluate the compatibility of two localized high-concentration electrolytes (LHCEs) with LiNi 0.96 Mg 0.02 Ti 0.02 O 2 (NMT) cathode under a high charging voltage of 4.4 V in lithium ion batteries. The LHCE with EC additive enables the formation of stable interfacial layers on both NMT cathode and graphite anode, thus realizing a capacity retention of 97.2% over 200 cycles at 25 °C and high reversible capacities of ~180.2 and ~185.8 mAh g -1 , respectively, at 5C charge rate and 5C discharge rate. This study offers a promising approach to enable Co-free ultrahigh-Ni layered oxides for practical applications.

25 ENERGY STORAGE↗
DOE OSTI2023

Superstructured NiMoO 4 @CoMoO 4 core-shell nanofibers for supercapacitors with ultrahigh areal capacitance

High areal capacitance for a practical supercapacitor electrode requires both large mass loading and high utilization efficiency of electroactive materials, which presents a great challenge. Herein, we demonstrated the unprecedented synthesis of superstructured NiMoO 4 @CoMoO 4 core-shell nanofiber arrays (NFAs) on a Mo-transition-layer-modified nickel foam (NF) current collector as a new material, achieving the synergistic combination of highly conductive CoMoO 4 and electrochemical active NiMoO 4 . Moreover, this superstructured material exhibited a large gravimetric capacitance of 1,282.2 F/g in 2 M KOH with a mass loading of 7.8 mg/cm 2 , leading to an ultrahigh areal capacitance of 10.0 F/cm 2 that is larger than any reported values of CoMoO 4 and NiMoO 4 electrodes. In conclusion, this work provides a strategic insight for rational design of electrodes with high areal capacitances for supercapacitors.

42 ENGINEERING↗
DOE OSTI2022

Electron Doping-Induced Metal–Insulator Transition in LaNiO 3 and Memory Devices

LaNiO 3 (LNO) is the only rare-earth nickelate that does not undergo a temperature-driven insulator-metal transition. Here, we report the successful deposition of epitaxial LNO thin films on LaAlO 3 substrates by a chemical solution deposition method. We report a metal-insulator transition driven by electron doping from hydrogen using catalytic Pd electrodes. A series of in-plane devices with LNO thin films and Pd-Au as the two working terminals were designed and fabricated by photolithography. Further, we report their resistance switching behavior and synaptic multiresistance states under voltage pulses. The results demonstrate the universality of electron doping-driven phase transitions in the rare-earth nickelates and their relevance to emerging memory and computing technologies.

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

Real Time Observation of Lithium Insertion into Pre-Cycled Conversion-Type Materials

Conversion-type electrode materials for lithium-ion batteries experience significant structural changes during the first discharge–charge cycle, where a single particle is taken apart into a number of nanoparticles. This structural evolution may affect the following lithium insertion reactions; however, how lithiation occurs in pre-cycled electrode materials is elusive. In this work, in situ transmission electron microscopy was employed to see the lithium-induced structural and chemical evolutions in pre-cycled nickel oxide as a model system. The introduction of lithium ions induced the evolution of metallic nickel, with volume expansion as a result of a conversion reaction. After pre-cycling, the phase evolutions occurred in two separate areas almost at the same time. This is different from the first lithiation, where the phase change takes place successively, with a boundary dividing the reacted and unreacted areas. Structural changes were restricted at the areas having large amount of fluorine, implying the residuals from the decomposition of electrolytes may have hindered the electrochemical reactions. This work provides insights into phase and chemical evolutions in pre-cycled conversion-type materials, which govern electrochemical properties during operation.

25 ENERGY STORAGE↗
DOE OSTI2022

Self-adhesive ionomers for durable low-temperature anion exchange membrane electrolysis

Low-temperature water electrolysis using an anion conductive polymer electrolyte has several potential advantages over other technologies, however, the fabrication of durable alkaline electrodes remains a challenge. Detachment of catalysts results in the loss of electrochemical surface area. Simple mixtures of ionomer and catalyst can suffer from poor catalyst adhesion because only physical adhesion is used to bind the components together. A family of chemically bonded, self-adherent, hydroxide conducting ionomers were synthesized and tested under alkaline electrolysis conditions with nickel ferrite anode electrocatalysts and platinum-nickel cathode catalyst. The ionomers are based on hydroxide conducting poly(norbornene) polymers used as the solid polymer electrolyte in alkaline fuel cells and electrolyzers. The synthesized terpolymer ionomers have been functionalized to provide pendant sites for covalent chemical bonding of bis(phenyl)-A-diglycidyl ether to the ionomer, catalyst, and porous transport layer. The electrodes show excellent adhesion between the catalyst particles, porous transport layer and ionomer, as determined by adhesion measurements and electrolysis performance. As a result, the AEM electrolyzer had stable voltage performance under high current density (1 A/ cm 2 at 1.83 V (67% voltage efficiency)) for extended time periods (>600 h) without degradation.

08 HYDROGEN↗
DOE OSTI2023

Reliable bi-functional nickel-phosphate /TiO2 integration enables stable n-GaAs photoanode for water oxidation under alkaline condition

Abstract Hydrogen is one of the most widely used essential chemicals worldwide, and it is also employed in the production of many other chemicals, especially carbon-free energy fuels produced via photoelectrochemical (PEC) water splitting. At present, gallium arsenide represents the most efficient photoanode material for PEC water oxidation, but it is known to either be anodically photocorroded or photopassivated by native metal oxides in the competitive reaction, limiting efficiency and stability. Here, we report chemically etched GaAs that is decorated with thin titanium dioxide (~30 nm-thick, crystalline) surface passivation layer along with nickel-phosphate (Ni-Pi) cocatalyst as a surface hole-sink layer. The integration of Ni-Pi bifunctional co-catalyst results in a highly efficient GaAs electrode with a ~ 100 mV cathodic shift of the onset potential. In this work, the electrode also has enhanced photostability under 110 h testing for PEC water oxidation at a steady current density J ph > 25 mA·cm −2 . The Et-GaAs/TiO 2 /Ni-Pi║Ni-Pi tandem configuration results in the best unassisted bias-free water splitting device with the highest J ph (~7.6 mA·cm −2 ) and a stable solar-to-hydrogen conversion efficiency of 9.5%.

08 HYDROGEN↗
DOE OSTI2020

Electrolyte Oxidation Pathways in Lithium-Ion Batteries

The mitigation of decomposition reactions of lithium-ion battery electrolyte solutions is of critical importance in controlling device lifetime and performance. However, due to the complexity of the system, exacerbated by the diverse set of electrolyte compositions, electrode materials, and operating parameters, a clear understanding of the key chemical mechanisms remains elusive. In this work, operando pressure measurements, solution NMR, and electrochemical methods were combined to study electrolyte oxidation and reduction at multiple cell voltages. Two-compartment LiCoO 2 /Li cells were cycled with a lithium-ion conducting glass–ceramic separator so that the species formed at each electrode could be identified separately and further reactions of these species at the opposite electrode prevented. One principal finding is that chemical oxidation (with an onset voltage of ~4.7 V vs Li/Li + for LiCoO 2 ), rather than electrochemical reaction, is the dominant decomposition process at the positive electrode surface in this system. This is ascribed to the well-known release of reactive oxygen at higher states-of-charge, indicating that reactions of the electrolyte at the positive electrode are intrinsically linked to surface reactivity of the active material. Soluble electrolyte decomposition products formed at both electrodes are characterized, and a detailed reaction scheme is constructed to rationalize the formation of the observed species. The insights on electrolyte decomposition through reactions with reactive oxygen species identified through this work have a direct impact on understanding and mitigating degradation in high-voltage/higher-energy-density LiCoO 2 -based cells, and more generally for cells containing nickel-containing cathode materials (e.g., LiNi x Mn y Co z O 2 ; NMCs), as they lose oxygen at lower operating voltages.

25 ENERGY STORAGE↗
DOE OSTI2022

Surface Stabilization with Fluorine of Layered Ultrahigh-Nickel Oxide Cathodes for Lithium-Ion Batteries

High-nickel layered oxide cathodes are key to meet the demands of the electric vehicle industry because of their high specific capacity. However, commercialization of these materials is hindered by critical challenges, such as phase transitions, particle cracking, aggressive surface reactivity, and thermal instability. Cation doping along with surface coating has proven to be an effective way to circumvent some of these issues to a large extent. Herein, fluorine coating is employed on a high-nickel Li[Ni 0.95 Mn 0.015 Co 0.02 Al 0.01 Mg 0.005 ]O 2 (NMCAM) cathode via a solution route. Detailed structural and electrochemical analyses indicate fluorine largely decorates the surface at low enough calcination temperatures. The cathode with 1 mol % fluorine coating exhibits a capacity retention of 71% after 500 cycles as compared to 59% for the control sample when cycled to a high cutoff voltage of 4.3 V in a full cell configuration with graphite anode. Post-mortem analysis of cycled electrodes reveals that surface reactivity is a major contributor to capacity fade as compared to particle cracking. Fluorine coating reduces surface reactivity and the depth to which rock-salt phase is formed on the surface during cycling. The thermal stability is also enhanced after fluorine coating as the material shows less heat release at high states of charge. Furthermore, this work demonstrates an effective, economical, and scalable way to stabilize the surface with fluorine and enhance the electrochemical performance of high-nickel cathodes.

25 ENERGY STORAGE↗
DOE OSTI2021

Valuation of Surface Coatings in High-Energy Density Lithium-ion Battery Cathode Materials

Artificial barriers, usually with either electrochemically active or inactive coating materials, are deployed on cathode material surfaces to mitigate detrimental side reactions by suppressing direct contact of cathode and electrolyte called surface coatings. These surface coatings are commonly known to increase the wettability of liquid electrolyte and reduce the interfacial charge transfer resistance. An important caveat is the selection of appropriate coating material with appropriate thickness for achieving enhanced electrochemical performance. As modern battery materials are increasingly developed with some type of surface coating, a careful and thorough examination of their role in mitigating the cycle life issues of cathode materials is paramount. Here, this comprehensive review article extensively covers the selection criteria of coating materials based on their chemical and physical properties and electrochemical functionalities. Additionally, the article discusses the concept of critical coating thickness and methods of achieving homogeneous coating architectures that deliver desired performance benefits. Furthermore, this comprehensive article summarizes the recent advancements, effectiveness, necessity of cathode surface coatings and identifies the key aspect of structure-property correlation between coating type/thickness and lithium-ion diffusion through coating layers as the linchpin that validates surface coating approaches especially for high capacity nickel-rich cathodes.

25 ENERGY STORAGE↗
DOE OSTI2026

Lattice-Oxygen-Driven Selective Oxidation Strategy for Stable Argyrodite Solid-State Lithium Metal Batteries

All-solid-state lithium metal batteries (ASSLMBs) with Li6PS5Cl argyrodite electrolytes and high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes offer high energy density but suffer from rapid capacity fading due to the layered-to-rock-salt transition of NMC811 and structural degradation of Li6PS5Cl from parasitic interfacial reactions. Here, we demonstrate a catholyte engineering strategy using a Li2S scavenging additive to suppress interfacial reactivity and preserve the structural and electrochemical stability of both NMC811 and Li6PS5Cl. Incorporating 0.10 wt.% Li2S enables exceptional cycling stability, achieving 76% capacity retention after 550 cycles at C/10 and 88% retention after 800 cycles at C/3 at 60 degrees C, compared with rapid failure in pristine cells. Spectroscopic, electrochemical, and morphological analyses confirm that Li2S maintains electrode integrity by sustaining particle contact and suppressing phase decomposition. This work elucidates interfacial degradation pathways in NMC811/argyrodite systems and introduces a low-cost, scalable strategy to stabilize nickel-rich oxide cathodes in ASSLMBs, advancing their practical viability.

25 ENERGY STORAGE↗
DOE OSTI2020

Molecular engineering of dispersed nickel phthalocyanines on carbon nanotubes for selective CO 2 reduction

Electrochemical reduction of CO 2 is a promising route for sustainable production of fuels. A grand challenge is developing low-cost and efficient electrocatalysts that can enable rapid conversion with high product selectivity. Here we design a series of nickel phthalocyanine molecules supported on carbon nanotubes as molecularly dispersed electrocatalysts (MDEs), achieving CO 2 reduction performances that are superior to aggregated molecular catalysts in terms of stability, activity and selectivity. The optimized MDE with methoxy group functionalization solves the stability issue of the original nickel phthalocyanine catalyst and catalyses the conversion of CO 2 to CO with >99.5% selectivity at high current densities of up to -300 mA cm -2 in a gas diffusion electrode device with stable operation at -150 mA cm -2 for 40 h. The well-defined active sites of MDEs also facilitate the in-depth mechanistic understandings from in situ/operando X-ray absorption spectroscopy and theoretical calculations on structural factors that affect electrocatalytic performance.

42 ENGINEERING↗
DOE OSTI2020

Systematic Study of the Cathode Compositional Dependency of Cross-Talk Behavior in Li-Ion Battery

While LiNi x Mn y Co 1-x-y O 2 (NMC) is one of the most widely used cathode materials for lithium-ion batteries (LIBs), the composition of NMC is evolving to Ni-rich NMC to achieve higher lithium capacity that fulfills the constant demand for LIBs with ever-higher energy densities. The change in the composition of NMC affects electrochemical features and electrode cross-talk, which explains the performance change during cycling. Here in this study, we introduce various NMC materials (LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.6 Mn 0.2 Co 0.2 O 2 and LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) to reveal how the NMC composition affects electrode cross-talk. The study reveals that NMC composition strongly affects transition metal dissolution; dissolution of manganese linearly decreases as its stoichiometric ratio in NMC decreases, while dissolution of nickel is only prominent in LiNi 0.8 Mn 0.1 Co 0.1 O 2 . Aged electrolyte samples are characterized with high-performance liquid chromatography, and two electrolyte decomposition species, C 8 H 16 O 5 and C 9 H 18 O 5 , are identified across all samples.

25 ENERGY STORAGE↗
DOE OSTI2020

Kinetic Limitations in Single-Crystal High-Nickel Cathodes

High-nickel cathodes attract immense interest for use in lithium-ion batteries, to boost Li-storage capacity while reducing cost. For overcoming the intergranular-cracking issue in polycrystals, single-crystals are considered an appealing alternative, but aggravating concerns on compromising the electrochemical kinetics of electrodes. We report here a quantitative assessment of electrochemical reaction in single-crystal LiNi 0.8 Mn 0.1 Co 0.8 O 2 using operando hard X-ray microscopy/spectroscopy, revealing a strong dependence of redox kinetics on the state of charge (SOC) - being sluggish at low SOC while increasing rapidly as SOC increases both in the bulk electrode and individual particles. The observation is corroborated by transport measurements and finite-element simulation, indicating that the sluggish kinetics in single-crystals is governed by ionic transport at low SOC and may be alleviated through synergistic interaction with polycrystals integrated into a same electrode. Finally, with the elucidated mechanistic origin and alleviation solution of kinetic limitations in single-crystal high-Ni cathodes, this work constitutes a step forward in enabling their practical deployment.

25 ENERGY STORAGE↗
DOE OSTI2021

Defect-free-induced Na + disordering in electrode materials

For reaching high-performance of electrode materials, it is generally believed that understanding the structure evolution and heterogeneous alignment effect is the key. Presently, a very simple and universally applicable self-healing method is investigated to prepare defect-free Prussian blue analogs (PBAs) that reach their theoretical capacity as cathode materials for sodium-ion batteries (SIBs). For direct imaging of the local structure and the dynamic process at the atomic scale, we deliver a fast ion-conductive nickel-based PBA that enables rapid Na + extraction/insertion within 3 minutes and a capacity retention of nearly 100% over 4000 cycles. This guest-ion disordered and quasi-zero-strain nonequilibrium solid–solution reaction mechanism provides an effective guarantee for realizing long-cycle life and high-rate capability electrode materials that operate via reversible two-phase transition reaction. Unconventional materials and mechanisms that enable reversible insertion/extraction of ions in low-cost metal–organic frameworks (MOFs) within minutes have implications for fast-charging devices, grid-scale energy storage applications, material discovery, and tailored modification.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Xerogel-Derived Ni Electrocatalysts for the Hydrogen Evolution Reaction in Alkaline Media

Anion exchange membrane water electrolyzers (AEMWEs) represent a promising technology for hydrogen production. The big advantage of the technology is that it allows for the use of platinum group metal-free (PGM-free) electrocatalysts at both electrodes, including catalysts for the hydrogen evolution reaction (HER) at the cathode. In addition to fulfilling the cost requirement, PGM-free HER catalysts need to meet the activity and durability targets of the AEMWEs. Here, in this work, we developed several carbon-supported, xerogel-derived nickel (Ni) HER electrocatalysts and evaluated the effect of various synthesis conditions, such as the type of carbon support, Ni-to-carbon ratio, and heat-treatment temperature and time, on their performance. Scanning transmission electron microscopy combined with energy-dispersive X-ray spectroscopy (STEM-EDS), X-ray diffraction spectroscopy (XRD), and X-ray photoelectron spectroscopy (XPS) revealed the formation of Ni nanoparticles with an oxygen-rich layer on the outside. Durability of the best-performing catalyst was assessed via a constant-current hold at 10 mA cm –2 over 100 h. This catalyst was found to be more active and durable than the reference PGM-free material, a commercial Ni catalyst supported on a Vulcan XC-72. The catalyst was also tested in the cathode of a fully PGM-free AEMWE, allowing to reach 1.90 V (1.84 V HFR-free) at 1 A cm –2 at 80 °C.

08 HYDROGEN↗