Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “cathode coating”

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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Constructing stable interface layer for boosting high-voltage cycling performance of single-crystal Ni-rich cathodes

Increasing demand for electric vehicles (EVs) worldwide and the requirements for environmental protection have greatly promoted the development of low-Co, Ni-rich layered cathodes due to their high energy density, reasonable cost, and less environmental pollution. Nevertheless, serious performance degradation and safety concerns resulting from structural/interfacial instability under high operating voltages (≥4.3 V) have greatly hindered its commercialization. Herein, we propose a feasible surface modification strategy by introducing a multifunctional Li 2 SiO 3 (LSO) coating layer onto the surface of Co less single-crystalline LiNi 0.63 Co 0.07 Mn 0.3 O 2 (NCM) to solve the above challenges. Additionally, the uniform Li 2 SiO 3 coating layer has a unique three-dimensional (3D) ion diffusion channel, which greatly promotes the transmission of Li + and alleviates interfacial stress accumulation. Equally important, the electrochemically inert Li 2 SiO 3 coating layer has a stable structure framework with strong Si-O bonds, which inhibit anisotropic particle volume expansion and the occurrence of side reactions during long-term cycling. As a consequence, LSO modified NCM exhibits greatly improved electrochemical properties even at harsh testing conditions and achieves capacity retention of 79.1% after 200 cycles at 25°C within 2.95-4.5 V in half cells. Furthermore, it provides an outstanding capacity retention of 94.7% after 300 cycles at 25°C within 2.95-4.4 V when tested in pouch full cells.

25 ENERGY STORAGE↗
DOE OSTI2025

Enabling fast-charging of lithium-ion batteries through printed electrodes

It has been well recognized that introducing secondary porous networks (SPNs) into the electrodes can effectively improve the electrochemical performance of lithium-ion batteries (LIBs), especially under fast-charging operations. However, the process complexity and high cost limit the commercial success of advanced electrodes with SPNs. To address this issue, we developed a facile screen-printing process to produce structured graphite electrodes with SPNs. The experimental results demonstrated that, by tuning the diameter and center-to-center (C2C) distance of emulsion dots on the stencil screen, the pore diameters and C2C pore distances of SPNs in screenprinted electrodes can be precisely controlled in the range of 100 mu m to 1 mm and 100 mu m to 3 mm respectively. In addition, the SPNs with hexagonal and square-shape pore alignments have also been imprinted onto the electrode coatings through adjusting the patterns of screen stencils. Used as anodes, the printed graphite electrodes demonstrated significantly reduced overpotential and voltage fluctuation under fast-charging operations from 2C to 6C. Coupled with LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) cathodes, the full cells with printed graphite anodes exhibited an unprecedently stable performance with almost no capacity decay up to 170 cycles when charged to 80 % SOC at 2C. Observations from electron microscopy showed plated lithium undetectable at the surface of printed graphite electrodes after numerous cycles. The electrochemical analysis on the voltage evolution during the cell rest period indicated the significantly delayed onset of lithium plating in the presence of printed graphite electrodes. In conclusion, all these results suggest that the significantly improved cell performance is associated with the shortened Li-ion diffusion distance, reduced polarization and suppressed Li plating in the printed electrodes with patterned SPNs.

25 ENERGY STORAGE↗
DOE OSTI2024

Detection of a Cobalt-Containing Interphase at the Li 6 PS 5 Cl-NMC111 Interface by In Situ μ XANES and EIS

Sulfide electrolyte all-solid-state lithium batteries (ASLBs) with uncoated Li-Ni x Mn y Co 1–x–y O 2 (NMC) cathodes suffer from a large capacity loss during initial cycling and an increase in cell impedance. Decomposition reactions are known to occur at the Li 6 PS 5 Cl-NMC111 interface due to incompatibility between the two materials. If a stabilizing coating is applied to the NMC, it delivers full capacity during initial charge. However, the loss in capacity during discharge still occurs. The interface was studied by μ XANES and through EIS analysis. A chemically-formed interphase was detected by μ XANES, evident from reduction of Co at an uncoated NMC particle surface. This interphase was produced by decomposition at rest. To study the effect of the interphase on electrochemically active surface area, piecewise in situ EIS was performed and the data was modeled using a transmission line model (TLM). The charge transfer resistance R CT was used to estimate the volume specific active surface area (a act ). The median value for a act was 296 cm –1 , a factor of 7.5 lower than the theoretical value of 2216 cm –1 . This provided evidence of a lower electrochemically active surface area in the ASLB.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Self-Stabilized LiNi 0.8 Mn 0.1 Co 0.1 O 2 in thiophosphate-based all-solid-state batteries through extra LiOH

Nickle-rich LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NMC 811) cathode material exhibits engaging properties in high energy density and low cost, making it great potential for the next generation high-energy all-solid-state lithium batteries (ASSLBs). However, NMC 811 suffers from severe surface electrochemical, chemical, and voltage incompatibility towards solid-state electrolytes (SSE), especially thiophosphate-based electrolytes like Li 6 PS 5 Cl. Although diverse coating methods have been made to overcome this issue, they are typically cumbersome and expensive. A coating strategy that satisfied all the requirements of cost-efficiency, stability, uniformity, scalability, and easy-achieving is still challenging. Here, we developed a LiOH-based surface stabilization strategy that provides a ~10 nm stable permeable layer on NMC 811. After one-step sintering of NMC 811 precursor mixed with LiOH, which is commonly used for NMC 811 lithiation process, excessive LiOH simultaneously distributes on NMC 811 particles. Unlike other reported methods, this coating method can be easily controlled and fabricated without additional complicated processes. By simply controlling the thickness of LiOH layer, which protects the Li 6 PS 5 Cl solid electrolyte materials from being oxidized, optimized cycling stability can be obtained for 600 cycles with capacity of 130 mAh g – 1 on average at a wide electrochemical window of 2.50–4.20 V (vs. Li-In).

25 ENERGY STORAGE↗
DOE OSTI2026

Production and installation of wavelength-shifting reflective light enhancers for the Short-Baseline Near Detector

We report on the design, production, and installation of a wavelength-shifting reflective system on the cathode of the Short-Baseline Near Detector (SBND), a liquid argon time projection chamber located along the Fermilab Booster Neutrino Beam. To increase and homogenize scintillation-light collection, 64 double-sided plates were fabricated from FR4, laminated with specular reflector film and coated with 300 $μ$g/cm$^2$ of tetraphenyl butadiene (TPB) wavelength shifter using controlled physical vapor deposition. The coating uniformity was validated through dedicated measurements of deposited mass and profilometry studies. Because exposure to ambient blue/UV light could degrade the TPB, protective filtering and controlled storage conditions were implemented during handling and installation. The coated plates were assembled between conductive meshes for high-voltage compatibility and installed in situ during detector integration. This system constitutes the largest TPB-coated area deployed in a neutrino detector. It operates in conjunction with SBND's photon detection system, which consists of photomultiplier tubes and X-ARAPUCAs. Early light-collection measurements show high uniformity and light response across the detector, supporting improved triggering, calorimetry, and position reconstruction in SBND.

Acciarri, R. [Fermilab]↗
DOE OSTI2025

Investigating the impact of preparation routes on the properties of copper-decorated silicon particles as anode materials for lithium-ion batteries

In recent years, the calendar life of Si has been recognized as a significant issue that must be addressed prior to technology deployment: The carbon conductive additive is a potential source of parasitic side reactions. However, carbon remains essential due to the low electronic conductivity of Si. In this study, we investigate the use of Cu as a conductive additive and potential alternative to carbon. Some Cu-decorated silicon particles (Si Cu ) were prepared using physical vapor deposition (PVD) via sputtering and high-energy milling. Other Si Cu particles were prepared by using a solution method and examined briefly. The milling method caused Cu to appear as island-like features on the Si surface, whereas the PVD method initially produced similar island-like features that gradually developed into a continuous coating around the Si as sputtering time increased. Electrodes fabricated from Si Cu exhibited lower overall resistivity, demonstrating the beneficial effect of Cu in improving electronic percolation through the electrode. Electrochemical tests showed that the milled SiCu exhibited higher capacity retention, improved rate capability, and lower overpotential. Furthermore, Si Cu coupled with an NMC811 cathode exhibited lower leakage currents compared with the baseline silicon, indicating that incorporating Cu provided an additional advantage of minimizing parasitic currents in the cells.

25 ENERGY STORAGE↗
DOE OSTI2026

Influence of CO 2 -Regenerative Film Properties in Enhancing C 2+ Products Selectivity While Mitigating CO 2 Crossover

Zero-gap anion-exchange membrane electrode assembly (AEMEA) electrolyzers operating in alkaline media face challenges such as CO 2 crossover and salting-out. The bipolar membrane electrode assembly (BPMEA) electrolyzer, using DI water as the electrolyte, addresses both CO 2 crossover and salting-out issues. As cations, which are crucial in stabilizing the CO 2 R intermediates, are absent in the electrolyte, cations embedded in the AEM play an important role in dictating the CO 2 R selectivity and activity in BPMEA systems. So far, no systematic study has been conducted on the influence of cations embedded in AEMs on CO 2 selectivity and activity in BPMEA systems. Moreover, BPMEA systems impose an additional challenge: low stability due to delamination of the bipolar membrane caused by CO 2 regeneration at the membrane-membrane interface. To enhance the stability of the electrolyzer, a simple yet highly reproducible strategy for coating a porous CO 2 regenerative film on smooth Nafion 117 is demonstrated in this work, along with a systematic study of four different commercially available AEMs, composed of different cations and cation densities, for use in combination with Nafion 117 and copper catalyst at the cathode. We found that the PiperION membrane delivers selectivity and activity comparable to those of alkali-metal cations, owing to the enhanced local electric field resulting from the combined effects of a high positive charge on the N atom of the piperidinium cation and the high ion-exchange capacity. Further, we studied the influence of the thickness of the PiperION porous layer over Nafion 117 on CO 2 R selectivity and found that 70 μm is the minimum thickness to achieve maximum C 2+ products selectivity, reduced the CO 2 crossover to 5% from 25% at 4 SCCM and 150 mA cm –2 , and was stable for operation beyond 100 h. The selectivity of this system, compared with AEMEA, and stability outperformed both AEMEA and BPMEA. This study helps design more effective BPMs to inhibit CO 2 crossover while enabling stable and selective electrochemical CO 2 reduction to C 2+ hydrocarbons.

Cations↗
DOE OSTI2021

The Impact of Anomalous Resistivity in Vacuum Contaminant Plasmas on the Electrothermal Instability

This manuscript presents an assessment of the electrothermal instability (ETI) in the presence of anomalous resistivity (AR) in vacuum contaminant plasmas (VCP) when applied to a magnetized liner inertial fusion (MagLIF)-like load.Pulsed-power driven dielectrically coated metallic liners, like in MagLIF, experience the current-driven electrothermal instability which occurs when a material’s resistivity changes with temperature and is subject to ohmic heating. Large scale pulsed-power facilities that use magnetically insulated transmission lines (MITL) have been shown to generate low-density plasma which enters the target chamber and coalesces around the load. The low-density high-temperature vacuum contaminant plasmas (VCP) can parasitically divert current from the load through causing a short in the anode-cathode gap inside the target chamber. Resistive magnetohydrodynamic (MHD) simulations of these VCP experience unphysical runaway ohmic heating due to under predicting the resistivity by using a purely collisional resistivity model.AR provides a physics-based way to address this runaway heating through increasing the resistivity in a proportional way with the drift speed. In this work, 1D simulations probe the effect that AR in VCP has on the magnetic diffusion rate, and 2D simulations show how this effect manifests in the nonlinear striation form of the ETI for a MagLIF-like load. Beryllium and aluminum dielectrically coated liners are used for the 1D and 2D simulations in this work. The1D simulations show that a VCP causes a delay in the current delivery to the load by upwards of 8 ns at 60 ns into atypical current pulse for an 1 × 10 7 A scale pulsed-power accelerator. The 2D simulations show the delay observed in the 1D simulations is reduced substantially (4 ns) by 2D turbulence that disrupts the VCP layer early in time. Here, the 2Dsimulated ETI growth varies across AR models, more so for the beryllium liner than the aluminum liner because the beryllium liner shows an enhanced rate of penetration for the magnetic diffusion wave in comparison to the aluminum liner. The 2D simulations show the bulk dielectric thickness varies across AR models with the Davidson AR model beingthe largest and the Buneman AR model being the smallest, and in connection with the thickness the Rayleigh-Taylor bubble-spike distances varies correspondingly.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Shelf-life of ball-milled catalyst inks for the fabrication of fuel cell electrodes

A major factor driving fuel cell costs is the quantity of precious metal required. Therefore, it is important to understand a timeframe where inks can be reused. Here, in this work, we explore differences between a freshly prepared catalyst ink and one that has been stored for over a year – comparing ink properties, cathode catalyst layer microstructure, and their respective fuel cell performance. Ink studies revealed smaller agglomerate sizes and a decrease in shear viscosity for the aged ink. Longer storage time also results in fewer cracks and a more uniform ionomer distribution, as evidenced by microscopy characterization of rod-coated electrodes. Lastly, polarization curves show improved performance at higher current densities for the electrode prepared from the aged ink. We rationalize such effect in terms of enhanced ionomer adsorption onto the catalyst over time.

08 HYDROGEN↗
DOE OSTI2022

Coupled continuum and network model framework to study catalyst layers of polymer electrolyte fuel cells

The nanostructured thin film (NSTF) catalyst layers which have demonstrated high power densities, mass activities, and exceptional metal and support stability can have limited operational robustness due to their thin thickness and the hydrophilicity of the metal-coated nano whiskers. The dispersed nanostructured thin film (dNSTF) catalyst layers have been developed by dispersing the NSTF Pt whiskers with ionomer and carbon support to increase the thickness and hydrophobicity. Continuum and network models (NM) are coupled through boundary conditions to study the polymer electrolyte fuel cell with a dNSTF cathode catalyst layer. The coupled model combines the computational efficiency of the continuum model with the pore-scale information in the dNSTF cathode catalyst layer of the NM. It captures the special morphology of the partially ionomer/water covered cylindrical whiskers, as well as water percolation through the pore structures and their impact on the cell performance. Here we observe optimal ionomer coverage on whiskers to be 0.5, ionomer to carbon ratio to be 0.9 and higher whisker to carbon ratios to be desired.

08 HYDROGEN↗
DOE OSTI2023

Long-term durability test of highly efficient membrane electrode assemblies for anion exchange membrane seawater electrolyzers

Direct seawater electrolysis faces fundamental electrochemical challenges, such as suppression of chlorine adsorption and/or evolution reactions that poison the current state-of-the-art anode catalysts and accelerate the degradation of the anion exchange membrane (AEM). The technically favored solution path for addressing these issues includes development of novel selective catalysts and implementation of limited operating conditions. Therefore, development of highly active, selective, cost-effective, and stable seawater-splitting catalysts is required for a successful commercialization of the AEM water electrolyzers (AEMWEs). In this work, we report for the first-time an extended operation for over 1000 h of advanced AEMWEs, operating directly with seawater. To fabricate the membrane electrode assemblies (MEAs), catalyst coated electrodes (CCEs) are assembled with Sustainion® X37-50 grade T anion exchange membranes. The anode CCEs are fabricated by spraying an ink prepared from nanostructured NiFe-layered double hydroxide (LDH) catalyst that are synthesized by the solvothermal method and deposited directly onto platinized titanium porous transport layers (PTLs). The cathode CCEs are prepared by spraying an ink prepared from commercial Renay-Nickel catalyst onto a nickel fiber felt. As prepared AEM electrolyzer cells operated with seawater and demonstrated better than previously reported in the literature performance of over 1000 h of operation at a constant current density of 300 mA cm –2 .

25 ENERGY STORAGE↗
DOE OSTI2025

Influence of AA6061 surface preparation on the resistance to surface degradation of thermally grown boehmite films

Understanding substrate–coating interactions is crucial for designing durable, corrosion-resistant systems. This study investigates the effects of surface treatments— polishing, acid etching, and alkaline etching—on AA6061 aluminum alloy and its thermally grown boehmite coatings. Surface treatments were found to significantly alter boehmite film properties by modifying the alloy’s surface composition. X-ray photoelectron spectroscopy revealed a 10% alumina drop after acid etching alongside chemisorbed species formation in wet treatments. Structural analysis, including grazing incidence X-ray diffraction and TEM, showed α-Al 2 O 3 formation on polished surfaces, improving wear resistance but inducing cathodic E corr shifts, pointing to higher corrosion susceptibility. In contrast, acid and alkaline etching produced anodic E corr shifts with stable, pit-free films observed via potentiodynamic scans. Electrochemical impedance spectroscopy highlighted reduced oxide resistance with extended boehmite growth. The findings emphasize the role of surface pre-treatments and boehmite optimization in balancing durability and corrosion resistance for AA6061 substrates.

AA6061↗
DOE OSTI2023

Design of the Lanthanum hexaboride based plasma source for the large plasma device at UCLA

The Large Plasma Device (LAPD) at UCLA (University of California, Los Angeles) produces an 18 m long, magnetized, quiescent, and uniform plasma at a high repetition rate to enable studies of fundamental plasma physics. Here, we report on a major upgrade to the LAPD plasma source that allows for more robust operation and significant expansion of achievable plasma parameters. The original plasma source made use of a heated barium oxide (BaO) coated nickel sheet as an electron emitter. This source had a number of drawbacks, including a limited range of plasma density (≲4.0 × 10 12 cm −3 ), a limited discharge duration (∼10 ms), and susceptibility to poisoning following oxygen exposure. Further, the new plasma source utilizes a 38 cm diameter lanthanum hexaboride (LaB 6 ) cathode, which has a significantly higher emissivity, allowing for a much larger discharge power density, and is robust to exposure to air. Peak plasma density of up to 3.0 × 10 13 cm −33 in helium gas has been achieved. The typical operating pressure is ∼10 −5 Torr, while dynamic pressure can be achieved through the gas-puffing technique. Discharges as long as 70 ms have been produced, enabling a variety of long-time-scale studies of processes, such as turbulent particle transport. The new source has been in continuous operation for 14 months, having survived air leaks, power outages that led to rapid temperature changes on the cathode and heater, and planned machine openings. We describe the design, construction, and initial operation of this novel new large-area LaB6 plasma source.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Relationship of Chemical Composition and Moisture Sensitivity in LiNi x Mn y Co 1-x-y O 2 for Lithium-Ion Batteries

Chemical composition–moisture sensitivity relationship of LiNi x Mn y Co 1-x-y O 2 (NMC) cathode materials was investigated by exploring crystal structures, surface properties, and electrochemical performance behaviors of various commercial NMC powders: LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC111), LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532), LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811). The NMC powders were stored in different moisture conditions: moisture-free, humidified air, or immersed in water. Rietveld refinement analysis of X-ray diffraction (XRD) data and scanning electron microscopy (SEM) were used to characterize the crystal structure changes and the evolution of particle surfaces morphologies. The effect of moisture contamination on the electrochemical properties of NMC cathodes was studied by galvanostatic cycling and electrochemical impedance spectroscopy (EIS). The moisture contamination resulted in either structural disorder or unwanted surficial deposition products, which increased a charge-transfer impedance and consequent performance degradation of battery cells. The results showed that NMC’s moisture vulnerability increased with Ni content (x) despite protective coatings on commercial particles, which stressed the necessity of alternative surface passivation strategies of Ni-rich NMC for broad applications such as electric vehicles and electrified aircraft propulsion.

25 ENERGY STORAGE↗
DOE OSTI2024

Stabilizing Nickel‐Rich Cathodes in Aqueous Process through Nanocellulose as Water Barrier

Nickel-rich LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NMC 811) cathode offers high voltage and high specific capacity, making it promising for high energy density batteries. However, large-scale manufacturing of aqueous-processed NMC 811 electrodes remains challenging due to proton exchange causing material decomposition and capacity loss. This work addresses this issue by constructing an in situ nanocellulose protective layer for NMC 811 particles via electrostatic interactions during the slurry preparation. For the first time, the interatomic spacing between inter-chains of nanocellulose is measured through wide-angle X-ray scattering and demonstrate the ability to effectively confine interlayer water using atomistic simulations. Moreover, this nanocellulose coverage simultaneously minimizes Li + surface segregation and mitigates water infiltration. Owing to less material decomposition during the aqueous processing, nanocellulose-protected NMC electrodes exhibit higher initial coulombic efficiency (83% vs 62% at 0.1C) and capacity (133 vs 59 mAh g −1 at 6C) than unprotected electrodes. Additionally, optimized aqueous-processed NMC electrodes offer comparable or even superior electrochemical properties compared to the electrodes fabricated using the conventional toxic organic solvent, N-methyl-2-pyrrolidone. Consequently, the developed approach enables affordable, sustainable aqueous processing for Nickel-rich NMC 811 cathodes with excellent electrochemical performances.

25 ENERGY STORAGE↗
DOE OSTI2023

Aerosol Manufacturing Technology to Produce Low-Cobalt Li-ion Battery Cathodes

Although considerable progress has been made with battery materials over the last 10 years, the cathode remains a major performance-limiting material in Li-ion battery (LIB) technology. New materials and battery chemistries will overcome some of the remaining challenges, but cathode materials must also be manufactured at a lower cost and with a smaller environmental footprint using new processes that can also enable improved control over stoichiometry, morphology, and compositional homogeneity. Cabot, Argonne National Laboratory and SAFT research teams are combining their extensive expertise in particle synthesis, battery materials and cell design to develop a low-cost, flexible aerosol manufacturing technology for production of high-performance cathode active materials (CAM). This project will develop low-Co CAMs via Reactive Spray Technology (RST) and Flame Spray Pyrolysis (FSP) to reach performance targets of < 50 mg Cobalt/Wh.

25 ENERGY STORAGE↗
DOE OSTI2021

Catalyst coating of a perovskite film and particles exsoluted from the perovskite film

A hybrid catalyst coating composed of a conformal thin film with exsoluted PrOx nano-particles. The conformal PNM thin film can be a perovskite composition of PrNi0.5Mn0.5O3 (PNM). The PrOx nano-particles dramatically enhance the oxygen reduction reaction kinetics via a high concentration of oxygen vacancies while the thin PNM film effectively suppresses strontium segregation from the cathode of an intermediate-temperature solid oxide fuel cell.

Liu, Meilin↗