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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 55 records · Page 3

MIL-101(Fe) as a lithium-ion battery electrode material: a relaxation and intercalation mechanism during lithium insertion

The electrochemical performance of a MIL-101(Fe) metal–organic framework (MOF) as a lithium ion battery electrode is reported for the first time. Iron metal centers can be electrochemically activated. The Fe 3+ /Fe 2+ redox couple is electrochemically active, but not reversible over many cycles. A comparison between ex situ and in operando X-ray absorption spectroscopy (XAS) on the Fe K-edge is presented. Our results indicate that the capacity fade is related to a time dependent, irreversible oxidation of Fe 2+ to Fe 3+ . These results are key in proving the importance of in operando XAS measurements. The MOF side reaction with an electrolyte has been computationally modeled. These results provide further insights on the mechanism responsible for the MOF lack of reversibility. Future guidelines for improving the reversibility of MOFs used as electrodes in Li-ion batteries based on the fine-tuning of the electronic structure of the material are proposed.

25 ENERGY STORAGE↗

Tuning charge-discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

For LiMO 2 (M=Co, Ni, Mn) cathode materials, lattice parameters, a(b), contract during charge. Here we report such changes in opposite directions for lithium molybdenum trioxide (Li 2 MoO 3 ). A ‘unit cell breathing’ mechanism is proposed based on crystal and electronic structural changes of transition metal oxides during charge-discharge. Metal–metal bonding is used to explain such ‘abnormal’ behaviour and a generalized hypothesis is developed. The expansion of the metal-metal bond becomes the controlling factor for a(b) evolution during charge, in contrast to the shrinking metal-oxygen bond as controlling factor in ‘normal’ materials. The cation mixing caused by migration of molybdenum ions at higher oxidation state provides the benefits of reducing the c expansion range in the early stage of charging and suppressing the structure collapse at high voltage charge. These results may open a new strategy for designing layered cathode materials for high energy density lithium-ion batteries.

Zhou, Yong-Ning↗

Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion

Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 degrees C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

25 ENERGY STORAGE↗

Direct Visualization of Solid Electrolyte Interphase Formation in Lithium-Ion Batteries with In Situ Electrochemical Transmission Electron Microscopy

Complex, electrochemically driven transport processes form the basis of electrochemical energy storage devices. The direct imaging of electrochemical processes at high spatial resolution and within their native liquid electrolyte would significantly enhance our understanding of device functionality, but has remained elusive. In this work we use a recently developed liquid cell for in situ electrochemical transmission electron microscopy to obtain insight into the electrolyte decomposition mechanisms and kinetics in lithium-ion (Li-ion) batteries by characterizing the dynamics of solid electrolyte interphase (SEI) formation and evolution. Here we are able to visualize the detailed structure of the SEI that forms locally at the electrode/electrolyte interface during lithium intercalation into natural graphite from an organic Li-ion battery electrolyte. We quantify the SEI growth kinetics and observe the dynamic self-healing nature of the SEI with changes in cell potential.

25 ENERGY STORAGE↗

Towards high-energy and durable lithium-ion batteries via atomic layer deposition: elegantly atomic-scale material design and surface modification

Targeted at fueling future transportation and sustaining smart grids, lithium-ion batteries (LIBs) are undergoing intensive investigation for improved durability and energy density. Atomic layer deposition (ALD), enabling uniform and conformal nanofilms, has recently made possible many new advances for superior LIBs. The progress was summarized by Liu and Sun in their latest review [1], offering many insightful views, covering the design of nanostructured battery components (i.e., electrodes and solid electrolytes), and nanoscale modification of electrode/electrolyte interfaces. This work well informs peers of interesting research conducted and it will also further help boost the applications of ALD in next-generation LIBs and other advanced battery technologies.

Atomic Layer Deposition↗

NASA Aerospace Flight Battery Program: Generic Safety, Handling and Qualification Guidelines for Lithium-Ion (Li-Ion) Batteries; Availability of Source Materials for Lithium-Ion (Li-Ion) Batteries; Maintaining Technical Communications Related to Aerospace Batteries (NASA Aerospace Battery Workshop)

This NASA Aerospace Flight Battery Systems Working Group was chartered within the NASA Engineering and Safety Center (NESC). The Battery Working Group was tasked to complete tasks and to propose proactive work to address battery related, agency-wide issues on an annual basis. In its first year of operation, this proactive program addressed various aspects of the validation and verification of aerospace battery systems for NASA missions. Studies were performed, issues were discussed and in many cases, test programs were executed to generate recommendations and guidelines to reduce risk associated with various aspects of implementing battery technology in the aerospace industry. This document contains Part 1 - Volume I: Generic Safety, Handling and Qualification Guidelines for Lithium-Ion (Li-Ion) Batteries, Availability of Source Materials for Lithium-Ion (Li-Ion) Batteries, and Maintaining Technical Communications Related to Aerospace Batteries (NASA Aerospace Battery Workshop).

Manzo, Michelle A.↗

Lithium titanate hydrates with superfast and stable cycling in lithium ion batteries

Lithium titanate and titanium dioxide are two best-known high-performance electrodes that can cycle around 10,000 times in aprotic lithium ion electrolytes. Here we show there exists more lithium titanate hydrates with superfast and stable cycling. That is, water promotes structural diversity and nanostructuring of compounds, but does not necessarily degrade electrochemical cycling stability or performance in aprotic electrolytes. As a lithium ion battery anode, our multi-phase lithium titanate hydrates show a specific capacity of about 130 mA h g –1 at ~35 C (fully charged within ~100 s) and sustain more than 10,000 cycles with capacity fade of only 0.001% per cycle. In situ synchrotron diffraction reveals no 2-phase transformations, but a single solid-solution behavior during battery cycling. Here, so instead of just a nanostructured intermediate to be calcined, lithium titanate hydrates can be the desirable final destination.

25 ENERGY STORAGE↗

Electrokinetic Phenomena Enhanced Lithium-Ion Transport in Leaky Film for Stable Lithium Metal Anodes

The application of lithium (Li) metal anodes in Li metal batteries has been hindered by growth of Li dendrite which leads to short cycling life. Here a Li-ion-affinity leaky film as a protection layer is reported to promote a dendrite-free Li metal anode. The leaky film induces electrokinetic phenomena to enhance Li-ion transport, leading to a reduced Li-ion concentration polarization and homogenous Li-ion distribution. As a result, the dendrite-free Li metal anode during Li plating/stripping is demonstrated even at an extremely high deposition capacity (6 mA h cm -2 ) and current density (40 mA cm -2 ) with improved Coulombic efficiencies. A full-cell battery with the leaky-film protected Li metal as anode and high-areal-capacity LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM-811) (~4.2 mA h cm -2 ) or LiFePO 4 (~3.8 mA h cm -2 ) as cathode shows improved cycling stability and capacity retention, even at lean electrolyte conditions.

25 ENERGY STORAGE↗

Revisiting metal fluorides as lithium-ion battery cathodes

Metal fluorides, promising lithium-ion battery cathode materials, have been classified as conversion materials due to the reconstructive phase transitions widely presumed to occur upon lithiation. We challenge this view by studying FeF 3 using X-ray total scattering and electron diffraction techniques that measure structure over multiple length scales coupled with density functional theory calculations, and by revisiting prior experimental studies of FeF 2 and CuF 2 . Metal fluoride lithiation is instead dominated by diffusion-controlled displacement mechanisms, and a clear topological relationship between the metal fluoride F- sublattices and that of LiF is established. Initial lithiation of FeF3 forms FeF2 on the particle's surface, along with a cation-ordered and stacking-disordered phase, A-Li x Fe y F 3 , which is structurally related to alpha-/beta-LiMn 2+ Fe 3+ F 6 and which topotactically transforms to B- and then C-Li x Fe y F 3 , before forming LiF and Fe. Lithiation of FeF 2 and CuF 2 results in a buffer phase between FeF 2 /CuF 2 and LiF. Overall, the resulting principles will aid future developments of a wider range of isomorphic metal fluorides.

25 ENERGY STORAGE↗

Uncovering the binding nature of thiocyanate in contact ion pairs with lithium ions

Ion pair formation is a fundamental molecular process that occurs in a wide variety of systems, including electrolytes, biological systems, and materials. In solution, the thiocyanate (SCN–) anion interacts with cations to form contact ion pairs (CIPs). Due to its ambidentate nature, thiocyanate can bind through either its sulfur or nitrogen atoms, depending on the solvent. This study focuses on the binding nature of thiocyanate with lithium ions as a function of the solvents using FTIR, 2D infrared spectroscopy (2DIR) spectroscopies, and theoretical calculations. The study reveals that the SCN– binding mode (S or N end) in CIPs can be identified through 2DIR spectroscopy but not by linear IR spectroscopy. Linear IR spectroscopy shows that the CN stretch frequencies are too close to one another to separate N- and S-bound CIPs. Moreover, the IR spectrum shows that the S–C stretch presents different frequencies for the salt in different solvents, but it is related to the anion speciation rather than to its binding mode. A similar trend is observed for the anion bend. 2DIR spectra show different dynamics for N-bound and S-bound thiocyanate. In particular, the frequency–frequency correlation function (FFCF) dynamics extracted from the 2DIR spectra have a single picosecond exponential decay for N-bound thiocyanate and a biexponential decay for S-bound thiocyanate, consistent with the binding mode of the anion. Lastly, it is also observed that the binding mode also affects the line shape parameters, probably due to the different molecular mechanisms of the FFCF for N- and S-bound CIPs.

25 ENERGY STORAGE↗

Model-Instructed Design of Novel Charging Protocols for the Extreme Fast Charging of Lithium-Ion Batteries Without Lithium Plating

Relatively long recharge time of high-energy density lithium-ion batteries (LIBs) is one of the major obstacles to the widespread deployment of electric vehicles (EVs). Excessive fast charge of LIBs can cause severe safety issues, the most significant of which is lithium plating. In addition to the consumption of cyclable lithium, dendrite-like lithium plating can cause short-circuiting within the cell, which could lead to catastrophic failure. In addition to the developments of advanced electrolytes, active materials and electrodes, the fast charging capability of LIBs can be improved by using optimized charging protocol. In this paper, the Pseudo2D battery model is first used to screen some conventional charging protocols proposed for fast charging, including the constant-current constant-voltage charging (CCCV), constant-power constant-voltage charging (CPCV), multi-stage constant-current charging, and pulse current charging. A semi-optimal charging protocol is then developed by automatically modifying the charge current such that the cell is charged at close-to-maximum current without lithium plating. Based on the features of the semi-optimal protocol, two practical novel fast charging protocols are proposed which allow charging the cell at a higher rate without lithium plating. Through simulation, we show that the no-plating capacity after 10 min charge can be improved by up to ~10.7% compared to CCCV charging for a 2.5 mAh cm -2 cell and ~18.8% for a 4 mAh cm -2 cell, when the proposed charging protocols are used.

25 ENERGY STORAGE↗

Purification of Lithium-Ion Battery Black Mass through Tailored Alkaline Corrosion

Obtaining high-purity material outputs is crucial to the viability of novel process aimed at direct recycling of lithium-ion batteries. Metallic impurities in recycled cathodes have been shown to inhibit performance, thereby threatening mainstream acceptance of recycled battery products. Thus, shredded black mass (BM) must be purified to remove metallic contaminants, and specifically Al and Cu originating from the electrode current collectors. We herein explore a process to ionize solid copper and aluminum to ionic form based on tailored alkaline chemistry, without incurring damage to the target cathode material (Li(NixMnyCo1-x-y)O2; NMC). Al and Cu corrosion may be enhanced through the addition of chloride salt, elevated temperatures, and the use of ultrasonication - all of which disrupt the formation of passivating films on the metallic surface, and thereby increase corrosion rate. We demonstrate optimized parameters for Al and Cu corrosion both from a kinetic and overall process cost perspective. Further, we analyze the impact of these conditions on the structural (XRD, SEM), chemical (EDS, ICP), and electrochemical (impedance, cycling, dQ/dV) properties of NMC, and suggest that the present purification method does not significantly disrupt NMC performance. Finally, we present preliminary results from a promising bench-scale demonstration of this purification process applied to a simulated black mass.

ADVANCED PROPULSION SYSTEMS,ENERGY STORAGE↗

A Comprehensive Experimental Study on Microstructure‐Graded Graphite Anodes for Enhancing Fast‐Charging Capability of Lithium‐Ion Batteries

Lithium‐ion batteries with high gravimetric capacity density and improved cycle life performance under fast‐charging conditions are crucial for widespread electric vehicle (EV) adoption. This study investigates how designing graphite anode microstructure, specifically porosity, and particle‐size gradients, improves lithium‐ion (Li + ) transport during fast‐charging conditions. Three‐layered graphite anodes with varying porosity (24%, 36%, 46%) and particle size gradients (3, 5, 10 μm) were compared to a conventional single‐layered electrode in half‐cell configurations. At room temperature and high discharge rate (2C), both gradient structures showed significantly enhanced capacity retention (80% and 67% vs. 50%) compared to the conventional electrode, highlighting the effectiveness of microstructure engineering for fast charging. The study also investigated the temperature's impact on cycle life. After 200 cycles at 2°C and 45°C, all gradient structures demonstrated superior capacity retention (≈80%) compared to the conventional electrode (35%), suggesting the gradients mitigate degradation rate at high temperatures. Electrochemical impedance spectroscopy confirmed superior Li+ diffusion and lower resistivity in gradient electrodes. Simulations explored the influence of gradient profiles on reaction kinetics across the electrode thickness. Overall, this research demonstrates that the fast‐charging capability of graphite electrodes can be greatly enhanced by engineering the electrode microstructure, thereby making EV technology more accessible and appealing.

Ahmadi, Soma↗