Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Cathode”

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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Unrecoverable lattice rotation governs structural degradation of single-crystalline cathodes

Transitioning from polycrystalline to single-crystalline nickel-rich cathodes has garnered considerable attention in both academia and industry, driven by advantages of high tap density and enhanced mechanical properties. However, cathodes with high nickel content (>70%) suffer from substantial capacity degradation, which poses a challenge to their commercial viability. Here, leveraging multiscale spatial resolution diffraction and imaging techniques, we observe that lattice rotations occur universally in single-crystalline cathodes and play a pivotal role in the structure degradation. These lattice rotations prove unrecoverable and govern the accumulation of adverse lattice distortions over repeated cycles, contributing to structural and mechanical degradation and fast capacity fade. These findings bridge the previous knowledge gap that exists in the mechanistic link between fast performance failure and atomic-scale structure degradation.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Structural Reliability of Cathode Contact Materials in Planar SOFCs

Despite significant developments in material and stack design technologies to enhance performance, the long-term mechanical reliability of solid oxide fuel cells remained an issue. The contact between electrodes and interconnects (especially the cathode side) was identified as one of the weakest links in present generation planar solid oxide fuel cells. Computational modeling was used to gain valuable insights on the cathode contact sintering mechanics and bond reliability. A continuum viscous sintering model was incorporated into a commercial finite element analysis code to simulate contact material densification and evaluate the bond and stack mechanical reliability due to developed stresses from the contact layer sintering. The parameters required for the cathode contact material constitutive model were extracted from experiments conducted for the contact material development at PNNL. The effects of contact layer thickness and sintering conditions like temperature and pressure on the stack stresses and reliability were investigated.

SOFC, FEA, Reliability↗
DOE OSTI2020

A Thermodynamic Reassessment of Lithium-Ion Battery Cathode Calorimetry

This work demonstrates how staged heat release from layered metal oxide cathodes in the presence of organic electrolytes can be predicted from basic thermodynamic properties. These prediction methods for heat release are an advancement compared to typical modeling approaches for thermal runaway in lithium-ion batteries, which tend to rely exclusively on calorimetry measurements of battery components. These calculations generate useful new insights when compared to calorimetry measurements for lithium cobalt oxide (LCO) as well as the most common varieties of nickel manganese cobalt oxide (NMC) and nickel cobalt aluminum oxide (NCA). Accurate trends in heat release with varying state of charge are predicted for all of these cathode materials. These results suggest that thermodynamic calculations utilizing a recently published database of properties are broadly applicable for predicting decomposition behavior of layered metal oxide cathodes. Aspects of literature calorimetry measurements relevant to thermal runaway modeling are identified and classified as thermodynamic or kinetic effects. The calorimetry measurements reviewed in this work will be useful for development of a new generation of thermal runaway models targeting applications where accurate maximum cell temperatures are required to predict cascading cell-to-cell propagation rates.

25 ENERGY STORAGE↗
DOE OSTI2021

Critical Barriers to Successful Implementation of Earth-Abundant, Mn-Rich Cathodes for Vehicle Applications and Beyond: A Detailed Study of Low SOC Impedance

We report that earth-abundant, sustainable cathode chemistries based on Mn are increasingly attractive for enabling a broader portfolio of cathode oxides. The well-known class of lithium- and manganese-rich cathodes still represents very viable options. However, despite the important work on understanding the mechanisms of voltage fade, hysteresis, and oxygen activity, relatively little attention has been given to understanding the impedance characteristics of these electrodes. In particular, an anomalous rise in area specific impedance at lower states of charge, as well as overall impedance rise and surface damage due to electrolyte interactions, represent critical barriers to implementation. This work presents a comprehensive study of impedance behavior in cobalt-free, lithium- and manganese-rich electrodes. The use of a robust surface treatment allows for long-term behavior to be probed in the absence of surface damage, capacity loss, and impedance rise due to electrolyte interactions. The anomalous rise in impedance could not be correlated to surface changes, or surface phase formation, but could be directly correlated with the bulk processes of voltage fade and voltage hysteresis. The activated material can be explained as a percolating network of higher-voltage, layered-type sites having facile Li diffusion. Interspersed throughout this network are lower-voltage, disordered sites that represent a significant barrier.

25 ENERGY STORAGE↗
DOE OSTI2022

Electrochemical Modeling and Experimental Verification of Lithiation Gradients in Oxide Cathodes of Lithium-Ion Cells

Lithiated nickel-cobalt-manganese oxides, such as NCM523, are used in the positive electrode (cathode) of Li-ion cells. Using operando X-ray diffraction profilometry, lithiation gradients in the cathode matrix can be observed and quantified by expansion into Legendre polynomials with time-dependent weights. These weights (referred to as gradients) increase in magnitude when electric current flows through the cell, decrease during potentiostatic hold and finally relax to zero when the current is interrupted during open circuit rest. Both physics-based electrochemical models and operando X-ray experiments suggest that the time constants for gradient growth and abatement are primarily determined by ionic diffusion in the oxide particles, which in turn depends on their lithium content. In contrast, the magnitude of gradients depends mainly on the applied current. The X-ray profilometry provides a way of directly probing the formation and disappearance of Li gradients across the cathode during fast cycling, which can help to diagnose the effects of material degradation in the cells.

25 ENERGY STORAGE↗
DOE OSTI2023

Evaluation of Cathode Materials with Lithium-Metal Anodes: Baseline Performance and Protocol Standardization of Coin Cells

The collaborative evaluation of electrode materials across multiple research entities requires standardized electrochemical testing protocols to produce reliable, one-to-one comparisons between different systems of interest. Similar to the work done by Long et al. on protocol standardization for coin-cell testing with graphite anodes [J. Electrochem. Soc., 163, A2999, (2016)], here we introduce two standardized testing protocols designed to quickly evaluate important electrochemical properties of cathode materials using lithium-metal anodes. The two protocols measure kinetic and thermodynamic capacity losses, rate- and voltage-dependent cycling capacities, instabilities at high voltage and high cycling rate, and overpotentials at various states of charge. We then apply these protocols to four commercially available cathode materials to establish benchmark performance metrics that can be used to screen and evaluate new cathode materials.

25 ENERGY STORAGE↗
DOE OSTI2025

Mitigating Transition Metal Dissolution from Mn-rich Cathodes: Influence of Processing and Testing Methods

Manganese-rich oxides continue to gain interest with respect to the development of Earth-abundant options for lithium-ion cathodes. Of the unique challenges that hinder the respective performance of various classes of such materials, manganese dissolution still stands as a common theme. The work herein explores Li 3 PO 4 as a robust surface protection layer on a prototypical, Co-free, manganese-rich cathode in the way of a lithium- and manganese-rich oxide. The study highlights the critical importance of synthesis and processing in realizing optimal performance of a given surface treatment by comparing sol-gel and atomic layer deposition methods. Furthermore, cycling protocols are emphasized as a critical factor in adequately gauging the efficacy of surface protection strategies to mitigate manganese dissolution and the subsequent electrochemical consequence. Optimized Li 3 PO 4 coatings coatings on lithium- and manganese-rich cathode particles are shown to greatly mitigate capacity fade, impedance rise, pore/void formation and mechanical damage during long-term cycling.

Mallick, Subhadip [Argonne National Laboratory (AN↗
DOE OSTI2025

Lithium-Ion Batteries with Lithium Manganese Iron Phosphate Cathodes and Lithium Titanate Anodes: Linking Electrode Dynamics to Cell Performance

This study examines the electrochemical performance, impedance behavior, and aging mechanisms of lithium-ion cells pairing lithium manganese iron phosphate (LiMn 0.6 Fe 0.4 PO 4 , LMFP64) cathodes with lithium titanate (Li 4 Ti 5 O 12 , LTO) anodes. LMFP64 half-cells display distinct Fe and Mn redox plateaus at ∼3.5 and ∼4.1 V, respectively, and deliver excellent rate capability. Three-electrode measurements show that LMFP64 dominates cell impedance, which changes sharply across the Fe–Mn redox transition and decreases with increasing temperature (30 °C–50 °C). Voltage hysteresis arises mainly from the cathode, with higher C-rates shortening redox plateaus and broadening the transition region. Elevated temperature lowers impedance, especially near the Mn-redox and transition regions, but accelerates capacity fade. Post-cycling analyses of electrodes confirm structural stability of LMFP64 and indicate loss of lithium inventory (LLI) as the source of capacity fade. This LLI causes potential slippage between the LMFP64 and LTO electrodes, which decreases the Fe-redox plateau width. Long-term cycling highlights the critical role of electrode overhang: cathode overhang mitigates capacity fade by buffering lithium loss, whereas anode overhang cells experience faster capacity decline due to uncompensated lithium depletion. These results clarify LMFP64/LTO battery impedance evolution, thermal effects, and degradation pathways and provide insights for their applications in electric vehicles.

Area Specific Impedance↗
DOE OSTI2016

A Spinel-integrated P2-type Layered Composite: High-rate Cathode for Sodium-ion Batteries

Sodium-ion batteries (SIB) are being intensively investigated, owing to the natural abundance and low cost of Na resources. However, the SIBs still suffer from poor rate capability due to the large ionic radius of Na+ ion and the significant kinetic barrier to Na+-ion transport. Here, we present an Fd-3m spinel-integrated P2-type layered composite (P2 + Fd-3m) material as a high-rate cathode for SIBs. The P2 + Fd-3m composite material Na0.50Ni1/6Co1/6Mn2/3O2 shows significantly enhanced discharge capacity, energy density, and rate capability as compared to the pure P2-type counterpart. The composite delivers a high capacity of 85 mA h g-1 when discharging at a very high current density of 1500 mA g-1 (10C rate) between 2.0 and 4.5 V, validating it as a promising cathode candidate for high-power SIBs. The superior performance is ascribed to the improved kinetics in the presence of the integrated-spinel phase, which facilitates fast electron transport to coordinate with the timely Na+-ion insertion/extraction. The findings of this work also shed light on the importance of developing lattice doping, surface coating, and electrolyte additives to further improve the structural and interfacial stability of P2-type cathode materials and fully realize their practical applications in sodium-ion batteries.

Zheng, Jianming↗
DOE OSTI2019

Water-Processable P2-Na 0.67 Ni 0.22 Cu 0.11 Mn 0.56 Ti 0.11 O 2 Cathode Material for Sodium Ion Batteries

Sodium ion batteries offer a low-cost, sustainable, and environment-friendly solution to large-scale electrochemical energy storage systems. Layered oxides represent a family of promising cathode materials with a potential to improve the energy and power densities while reducing the material cost of sodium ion batteries. However, due to the chemical and structural instability of layered oxides in an aqueous solution, the current battery electrode manufacturing requires expensive and hazardous organic solvents, which impedes the full benefit of the low-cost, sustainable, and eco-friendly advantages. We need an effective technology that empowers a cathode with water processable properties. In this study, we set a representative example, P2-Na0.67Ni0.22Cu0.11Mn0.56Ti0.11O2, to explore its performance under water-processing conditions. This material achieves a discharge capacity of 180 mAh/g and a discharge energy of 544 Wh/kg at 22 ?C. The aging experiments indicate its superior stability against water, having negligible bulk 2 structural or chemical changes. The surface sensitive soft X-ray absorption spectroscopy shows that the P2-Na0.67Ni0.22Cu0.11Mn0.56Ti0.11O2 has stable surface chemistry in the aqueous solution. Moreover, the cells with water-processed cathodes delivered stable cycling performance with minor voltage decay, originating from the decreased cell impedance. Therefore, the present study sets a refined example to establish a low-cost, sustainable, and eco-friendly solution by developing water-processable electrode materials for sodium ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2017

Mixed Polyanion Glass Cathodes: Mixed Alkali Effect

In lithium-ion batteries, mixed polyanion glass cathodes have demonstrated high capacities (200-500 mAh/g) by undergoing conversion and intercalation reactions. Mixed polyanion glasses typically have the same fundamental issues as other conversion cathodes, i.e.: large hysteresis, capacity fade, and 1st-cycle irreversible loss. A key advantage of glass cathodes is the ability to tailor their composition to optimize the desired physical properties and electrochemical performance. The strong dependence of glass physical properties (e.g., ionic diffusivity, electrical conductivity, and chemical durability) on the composition of alkali mixtures in a glass is well known and has been named the mixed alkali effect. The mixed alkali effect on battery electrochemical properties is reported here for the first time. Depending on glass composition, the mixed alkali effect is shown to improve capacity retention during cycling (from 39% to 50% after 50 cycle test), to reduce the 1st-cycle irreversible loss (from 41% to 22%), and improve the high power (500 mA/g) capacity (from 50% to 67% of slow discharge capacity).

Kercher, A. K.↗
DOE OSTI2022

Python catemis package for DARHT Axis-II Dispenser-Cathode Emissivity and Temperature Analysis

The catemis python package includes the analysis methods used in paper "DARHT Axis-II Dispenser-Cathode Emissivity and Temperature", which was presented at the 2021 Weapons Engineering Symposium and Journal (WESJ) hosted by Los Alamos National Laboratory. The paper (LA-UR-21-25647) and presentation (LA-UR-21-28231) report on a temperature and emissivity model that has been developed and applied to data from diagnostics used to measure the surface temperature of the DARHT Axis-II hot dispenser cathode over more than a decade of operation. The catemis package provides all the methods used in reporting these results along with the data files used to create the plots and tables in the paper. This includes methods for loading and processing FAR spectral pyrometer data along with methods for temperature calibration of cathode images.

Koglin, Jason↗
DOE OSTI2019

Prospect and Reality of Concentration Gradient Cathode of Lithium-ion Batteries

Li[Ni x Co y Mn z ]O 2 cathodes are currently the most practicable materials in the timing of developing high performance rechargeable batteries for next generation technologies. With the ever growing demand for energy density, a significant breakthrough has been achieved by the controllable concentration design forming core shell and con centration gradient structures to push Li[Ni x Co y Mn z ]O 2 toward higher energy density, longer lifetime and safety. In this paper, we review the recent progress on advanced concentration gradient cathode materials. Furthermore, we prospect that this novel approach w ill continuously extend its advantages in developing extremely fast charging and Co free cathode materials in the near future.

25 ENERGY STORAGE↗
DOE OSTI2019

The development programme of cathodes and electron guns for the Hollow Electron Lenses of the High Luminosity LHC project1

The High Luminosity LHC project (HL-LHC) foresees the construction and installation of important new equipment to increase the performance of the LHC machine. The Hollow Electron Lens (HEL) is a promising system to control the beam halo. It improves the beam collimation system of the HL-LHC and mitigates possible equipment damage in case of failure scenarios from halo losses. The halo can store up to 30 MJ energy. The specifications for this new device are quite demanding. The source, an electron gun with an annular shaped cathode, has to deliver a current up to 5 A. This is five times higher than the current in the existing electron lenses in Fermi and Brookhaven national laboratories. This note describes the programme carried out to design and test high-perveance guns equipped with two types of high-performance scandate cathodes. The size of the final gun is now considerably smaller than the one of the first prototype, allowing a reduction of diameter and cost of the superconducting magnet system used to steer the electron beam. The tests carried out at FNAL, BVERI and BJUT demonstrated that the developed cathodes fulfil the specifications and can supply a 5 A fully Space Charge Limited (SCL) current.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Multifunctional, Self-Healing Polyelectrolyte Gels for Long-Cycle-Life, High-Capacity Sulfur Cathodes in Li-S Batteries (FY2020 Final Report)

The project aims to develop polyelectrolyte gels consisting of partially crosslinked ionomer, interpenetrated with self-healing/polysulfide-trapping chains and swelled with a mixture of room temperature ionic liquid (RTIL) and lithium salt. To our knowledge, no other sulfur-based cathode design has combined self-healing behavior, polysulfide containment, and lithium dendrite suppression into a single design. We have demonstrated the benefits of multifunctional ionomer gel polyelectrolytes / gel cathodes with self-healing properties, as well as chemical modification of mesoporous carbons for S/C composite cathodes. Success of the proposed program of study would have wide ranging impact on the electric vehicle industry and society as a whole. A Li-S battery system with the capability of doubling lithium-ion energy density would enable the production of lighter, longer range electric vehicles at a cost that is affordable to the average U.S. household. The availability of such vehicles should lead to wide-ranging adoption over the coming years which, in combination with increased renewable electricity generation, will drastically decrease carbon emissions across the country and reduce U.S. dependency on fossil fuel sources.

25 ENERGY STORAGE↗
DOE OSTI2016

Minimize the Voltage Degradation in Li-rich Layered Oxide Cathode Materials by Morphology Control

Li-rich layered oxides, either as a solid solution or as a nano-composite of layered Li 2 MnO 3 and Li(TM)O 2 (TM=Ni, Co, Mn), draw significant attention as the next-generation cathode materials for high-energy-density lithium ion batteries in electric vehicles. Over the past twenty years, the discharge capacity at room temperature of these cathode materials has been improved from 200 mAh g -1 to over 320 mAh g -1 today, even higher at elevated temperatures. While the research has continued to push the limit of the available capacity of the materials throughout the years, there are many issues still unclear. And numerous scientific challenges, especially voltage degradation during cycling of these materials, that must be overcome to realize their utilization in commercial lithium ion batteries. Here, we report a design of modified co-precipitation method without ammonia addition to synthesize morphology controlled Li-rich material Li 1.2 Ni 0.2 Mn 0.6 O 2 as high energy density cathode for lithium ion batteries. The obtained material has spherical secondary particles with uniform dispersion. The secondary particles are dense, and have an average diameter of approximately 3 μm. These secondary spherical particles consist of primary particles with particle size approximately 150 nm. The morphology controlled sample can minimize voltage decay as well as improve capacity retention during cycling. And furthermore, the influence of morphology control on the cycling performance has been investigated through Transmission X-ray Microscope.

Zhang, Minghao↗
DOE OSTI2022

High-Energy Solid-State Lithium Batteries with Organic Cathode Materials (Final Report)

Organic materials made from abundant elements via low-energy processes are emerging as sustainable and low-cost alternatives to transition metal oxides as the electrode materials for high- energy batteries in the wake of supply chain and environmental issues associated with critical materials during the transition to clean energy. Organic insertion materials (OIMs) offer material- level energy comparable to transition metal oxides, but they have durability difficulties owing to dissolving in common liquid electrolytes. Combining ceramic-based solid electrolytes with organic electrode materials is one intriguing solution. The goal of this project is to design and synthesize high-energy OIMs, to understand the chemical dynamics and mechanical properties at the OIM-sulfide interface during electrochemical cycling, and to develop methods for constructing the optimum cathode microstructure, which will lead to improved electrochemical performance. The project team has accomplished the following over the last four years: (a) demonstrating that the mechanical softness of organic electrode materials is uniquely beneficial in suppressing crack formation at the electrode-electrolyte interface during cell operation; (b) understanding the interaction between cathode microstructure and the mechanical properties of individual components; and (c) establishing predictive control of cathode microstructure by tuning the mechanical properties of solid electrolytes and OIMs; (d) determining the chemical combability of sulfide electrolyte with high-energy OIMs and finally (f) laying out a road map toward a specific energy of 500 Wh kg -1 for solid-state lithium batteries. 14 publications resulted from this project.

25 ENERGY STORAGE↗
DOE OSTI2022

Economic Analysis of Battery (NMC) Cathode Material Production in Flame Spray Process with Sustainable Solvents

To reduce the cathode material manufacturing cost, our lab has developed a flame spray process that utilize sustainable solvent glycerol as solvent to manufacture the cathode material. The economic analysis of the new green chemical process was studied based on discounted cash flow method. The major economic indicator used in this study is the minimum cathode material selling price (MCSP), whereas the co-precipitation method for NMC333 production was selected as the reference for economic analysis.

25 ENERGY STORAGE↗