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Results for “lithium intercalation”

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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Operando Measurements of Electrolyte Li-ion Concentration during fast charging with FTIR/ATR

The ability to charge a Li-ion battery at high charging rates is critical for electric vehicle adoption; however, further study of ion transport is required to develop electrolytes suitable for fast charge. Fourier transform infrared spectroscopy (FTIR) used with attenuated total reflection (ATR) enables operando measurements of liquid electrolytes. This research focused on solvation shifting of solvent infrared absorption bands in the presence of lithium ions. Lithium-shifted infrared absorption bands and non-shifted bands of ethyl methyl carbonate (EMC) and ethylene carbonate (EC) were compared to infer ion concentration changes during cycling. Lithium concentrations were calibrated using EC/EMC/LiPF 6 electrolytes with known lithium concentrations. A Li-ion half-cell with a graphite anode and EC/EMC/LiPF 6 electrolyte was observed with FTIR/ATR. The results showed that the magnitude of lithium concentration changes increased with increasing C-rate. During a galvanostatic intermittent titration technique (GITT) test, changes in lithium concentration could be observed. During intercalation, a lithium depletion occurred when a negative current was applied, and a lithium surplus occurred during deintercalation when a positive current was applied. The capability of observing lithium concentration has significant implications for the utility of operando studies and the potential to link lithium movement to battery performance.

25 ENERGY STORAGE↗
DOE OSTI2024

Lithiation Induced Phases in 1T'-MoTe 2 Nanoflakes

Multiple polytypes of MoTe 2 with distinct structures and intriguing electronic properties can be accessed by various physical and chemical approaches. Here, in this study, we report electrochemical lithium (Li) intercalation into 1T'-MoTe 2 nanoflakes, leading to the discovery of two previously unreported lithiated phases. Distinguished by their structural differences from the pristine 1T' phase, these distinct phases were characterized using in situ polarization Raman spectroscopy and in situ single-crystal X-ray diffraction. The lithiated phases exhibit increasing resistivity with decreasing temperature, and their carrier densities are two to 4 orders of magnitude smaller than the metallic 1T' phase, as probed through in situ Hall measurements. The discovery of these gapped phases in initially metallic 1T'-MoTe 2 underscores electrochemical intercalation as a potent tool for tuning the phase stability and electron density in two-dimensional (2D) materials.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Strain-retardant coherent perovskite phase stabilized Ni-rich cathode

The use of state-of-the-art Ni-rich layered oxides (LiNi x Co y Mn 1-x-y O 2 , x > 0.5) as the cathode material for lithium-ion batteries can push the energy and power density to a higher level than is currently available. However, volume variation associated with anisotropic lattice strain and stress that is being developed during lithium (de) intercalation induces severe structural instability and electrochemical decay of the cathode materials, which is amplified further when the battery is operating at a high voltage (above 4.5 V), which is essential for unlocking its high energy. Even after much effort by the research community, an intrinsic strain-retardant method for directly alleviating the continuous accumulation of lattice strain remains elusive. By introducing a coherent perovskite phase into the layered structure functioning as a ‘rivet’, we significantly mitigate the pernicious structural evolutions by a pinning effect. The lattice strain evolution in every single cycle is markedly reduced by nearly 70% when compared with conventional materials, which significantly enhances morphological integrity leading to a notable improvement in battery cyclability. This strain-retardant approach broadens the perspective for lattice engineering to release the strain raised from lithium (de)intercalation and paves the way for the development of high-energy-density cathodes with long durability.

25 ENERGY STORAGE↗
DOE OSTI2022

Onboard early detection and mitigation of lithium plating in fast-charging batteries

Fast-charging is considered as one of the most desired features needed for lithium-ion batteries to accelerate the mainstream adoption of electric vehicles. However, current battery charging protocols mainly consist of conservative rate steps to avoid potential hazardous lithium plating and its associated parasitic reactions. A highly sensitive onboard detection method could enable battery fast-charging without reaching the lithium plating regime. Here, we demonstrate a novel differential pressure sensing method to precisely detect the lithium plating event. By measuring the real-time change of cell pressure per unit of charge (dP/dQ) and comparing it with the threshold defined by the maximum of dP/dQ during lithium-ion intercalation into the negative electrode, the onset of lithium plating before its extensive growth can be detected with high precision. In addition, we show that by integrating this differential pressure sensing into the battery management system (BMS), a dynamic self-regulated charging protocol can be realized to effectively extinguish the lithium plating triggered by low temperature (0 °C) while the conventional static charging protocol leads to catastrophic lithium plating at the same condition. We propose that differential pressure sensing could serve as an early nondestructive diagnosis method to guide the development of fast-charging battery technologies.

25 ENERGY STORAGE↗
DOE OSTI2024

Role of Heterointerface in Lithium-Induced Phase Transition in T d -WTe 2 Nanoflakes

A new polytype of WTe 2 with a bandgap has been recently discovered through the intercalation of lithium into the van der Waals gaps of T d -WTe 2 . Here, we report the effects of reduced thicknesses and heterointerfaces on the intercalation-induced phase transition in WTe 2 . Using in situ Raman spectroscopy during the electrochemical lithiation of WTe 2 flakes as a function of flake thickness, we observe that additional electrochemical energy is required for the phase transition of WTe 2 from the T d phase to the new lithiated T d ' phase, going from 0.8 V of the applied electrochemical voltage for a thick flake to 0.5 V and 0.3 V for 7- and 5-layered samples, respectively. We ascribe this suppression of the phase transition to the interfacial interaction between the nanoflake and SiO 2 /Si substrate, which plays an increasing role as the sample thickness is reduced. The suppressed kinetics of the phase transition can be mitigated by placing the WTe 2 flake on a hexagonal boron nitride (hBN) flake, which facilitates the release of the in-plane strain induced by the phase transition. Importantly, our study underscores the significance of interfacial effects in modulating phase transitions in two-dimensional (2D) materials, suggesting heterogeneous transition pathways, as well as interfacial engineering to control these phase transitions.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Reaction Heterogeneity in LiFePO 4 Agglomerates and the Role of Intercalation-Induced Stress

As an important battery cathode material, reaction distribution in lithium iron phosphate (LiFePO4) has been extensively studied in dispersed particle systems, but remains poorly understood for mesoscopic agglomerates (or secondary particles) that are used in most commercial batteries. Herein, we apply three-dimensional X-ray spectroscopic imaging to characterize the two-phase structure in LiFePO4 secondary particles during electrochemical cycling. (De)lithiated domains are found to not form the commonly assumed core-shell structure but develop highly anisotropic filamentary morphology that is rate independent and symmetric between charging and discharging. Phase-field simulations elucidate that the observed 1D phase growth behavior is not caused by the 1D lithium diffusivity of LiFePO4 but the elastic interaction between primary particles, which gives rise to stronger reaction heterogeneity than dispersed nanoparticles. As a result, uniform lithium (de)intercalation does not occur on the secondary particle surface even at high cycling rates.

36 MATERIALS SCIENCE↗
DOE OSTI2021

3D Detection of Lithiation and Lithium Plating in Graphite Anodes during Fast Charging

A barrier to the widespread adoption of electric vehicles is enabling fast charging lithium-ion batteries. At normal charging rates, lithium ions intercalate into the graphite electrode. At high charging rates, lithiation is inhomogeneous, and metallic lithium can plate on the graphite particles, reducing capacity and causing safety concerns. We have built a cell for conducting high-resolution in situ X-ray microtomography experiments to quantify three-dimensional lithiation inhomogeneity and lithium plating. Our studies reveal an unexpected correlation between these two phenomena. During fast charging, a layer of mossy lithium metal plates at the graphite electrode–separator interface. The transport bottlenecks resulting from this layer lead to underlithiated graphite particles well-removed from the separator, near the current collector. These underlithiated particles lie directly underneath the mossy lithium, suggesting that lithium plating inhibits further lithiation of the underlying electrode.

25 ENERGY STORAGE↗
DOE OSTI2024

Electrochemical Control of the Ultrafast Lattice Response of a Layered Semimetal

The unique layer-stacking in two-dimensional (2D) van der Waals materials facilitates the formation of nearly degenerate phases of matter and opens novel routes for the design of low-power, reconfigurable functional materials. Electrochemical ion intercalation between stacked layers offers a promising approach to stabilize bulk metastable phases and to explore the effects of extreme carrier doping and strain. However, in situ characterization methods to study the structural evolution and dynamical functional properties of these intercalated materials remains limited. Here a novel experimental platform is presented capable of simultaneously performing electrochemical lithium-ion intercalation and multimodal ultrafast characterization of the lattice using both electron diffraction and nonlinear optical techniques. Using the layered semimetal WTe 2 as a model system, the interlayer shear phonon mode that modulates stacking between 2Dlayers is probed, showing that small amounts of lithiation enhance the amplitude and lifetime of the phonon, contrary to expectations. This results from the dynamically fluctuating and anharmonic structure between nearly degenerate phases at room temperature, which can be stabilized by electronic carriers accompanying the inserted lithium ions. At high lithiation, the T d ’ structure emerges and quenches the phonon response. This work defines new approaches for using electrochemistry to engineer the dynamic structure of 2D materials.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Understanding the limits of Li-NMC811 half-cells

As we push the boundaries of state-of-the-art lithium-ion intercalation materials, such as nickel-rich chemistries, the ability to isolate and understand specific degradation and performance limitations is becoming increasingly important. Half-cells, wherein lithium metal is employed as a dual counter and reference electrode, are commonly used in industry and academia for this purpose. However, the high reactivity of lithium metal drives premature electrolyte degradation and limits cell lifetime, bringing into question the reliability and validity of this cell configuration. Here we explore the limitations of half-cell studies of LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) electrodes with commercially relevant loading. We identify the failure mechanism of this cell configuration through a combination of electrochemical, chemical, and spectroscopic techniques and show that the Li has a direct detrimental impact on the NMC811 chemistry. Our measurements show that vinylene carbonate is critical for these half-cell studies and underpins the cycle limits. Furthermore, we demonstrate the use of Li 4 Ti 5 O 12 (LTO) as an alternative counter electrode for understanding the performance of NMC positive electrode materials, due to its high coulombic efficiency and low reactivity with the organic carbonates routinely employed in lithium-ion battery cell chemistries. These data confirm that NMC811 electrodes can tolerate high voltages (stressed) conditions and that cell failure is mainly a result of crossover effects.

25 ENERGY STORAGE↗
DOE OSTI2024

Relithiation process for direct regeneration of cathode materials from spent lithium-ion batteries

A method for the regeneration of cathode material from spent lithium-ion batteries is provided. The method includes dissolving a lithium precursor in a polyhydric alcohol to form a solution. Degraded cathode material containing lithium metal oxides are dispersed into the solution under mechanical stirring, forming a mixture. The mixture is heat treated within a reactor vessel or microwave oven. During this heat treatment, lithium is intercalated into the degraded cathode material. The relithiated electrode material is collected by filtration, washing with solvents, and drying. The relithiated electrode material is then ground with a lithium precursor and thermally treated at a relatively low temperature for a predetermined time period to obtain regenerated cathode material.

Belharouak, Ilias↗
DOE OSTI2026

A Parallel Kinetic Model for Surface and Bulk Charge Storage in ε -MnO 2 Pseudocapacitors

Pseudocapacitive materials such as manganese dioxide (MnO 2 ) are attractive for energy storage applications due to their ability to combine the fast kinetics of capacitors with the higher energy density of battery-type systems. However, the electrochemical behavior of MnO 2 remains difficult to interpret mechanistically, in part because existing models often fail to distinguish between surface-based redox processes and bulk intercalation mechanisms. In this work, we develop a physics-based model that represents MnO 2 pseudocapacitance as a linear combination of two independent, parallel electrochemical processes: (i) the surface or near-surface redox storage and (ii) lithium ion intercalation into the bulk material. These two processes are treated with distinct kinetic and thermodynamic parameters and are assumed to proceed independently. The total measured current is assumed to be the sum of these two partial currents. We validate the model using rate-dependent cyclic voltammetry experiments, demonstrating that it captures key trends and provides physically interpretable parameters reflecting the relative contributions of surface and bulk processes. By enabling a clear separation between these mechanisms, the model offers a useful framework for analyzing pseudocapacitive materials and can guide the rational design of high-performance energy storage electrodes.

Energy - Storage↗
DOE OSTI2023

Electronic signatures of Lorentzian dynamics and charge fluctuations in lithiated graphite structures

Lithium graphite intercalation compounds (Li-GICs) are essential materials for modern day portable electronics and obtaining insights into their atomic structure and thermodynamics is of fundamental interest. Here we explore the electronic and atomic states of Li-GICs at varying degrees of Lithium loading (i.e., “staging”) by means of ab-initio molecular dynamics simulations and simulated X-ray adsorption spectroscopy (XAS). We analyze the atomic correlation functions and shows that the enhancements of the Li-ion entropy with increased staging result from Lorentzian lithium-ion dynamics and charge fluctuations, which activate low-energy phonon modes. The associated electronic signatures are modulations of the unoccupied π*/σ* orbital energy levels and unambiguous fingerprints in Carbon K-edge XAS spectra. Thus, we extend the canonical view of XAS, establishing that these “static” measurements in fact encode the signature of the thermodynamic response and relaxation dynamics of the system. This causal link between atomic structure, spectroscopy, thermodynamics, and information theory can be generally exploited to better understand stability in solid-state electrochemical systems.

25 ENERGY STORAGE↗
DOE OSTI2021

Revisiting Discharge Mechanism of CF x as a High Energy Density Cathode Material for Lithium Primary Battery

Lithium/fluorinated graphite (Li/CFx) primary batteries show great promise for applications in a wide range of energy storage systems due to their high energy density (>2100 Wh kg –1 ) and low self-discharge rate (<0.5% per year at 25 °C). While the electrochemical performance of the CF x cathode is indeed promising, the discharge reaction mechanism is not thoroughly understood to date. In this article, a multiscale investigation of the CF x discharge mechanism is performed using a novel cathode structure to minimize the carbon and fluorine additives for precise cathode characterizations. Titration gas chromatography, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, cross-sectional focused ion beam, high-resolution transmission electron microscopy, and scanning transmission electron microscopy with electron energy loss spectroscopy are utilized to investigate this system. Results show no metallic lithium deposition or intercalation during the discharge reaction. Crystalline lithium fluoride particles uniformly distributed with <10 nm sizes into the CF x layers, and carbon with lower sp2 content similar to the hard-carbon structure are the products during discharge. This article deepens the understanding of CF x as a high energy density cathode material and highlights the need for future investigations on primary battery materials to advance performance.

25 ENERGY STORAGE↗
DOE OSTI2022

Computational Modeling of Battery Materials

This chapter provides a broad overview of the various computational modeling techniques used to gain fundamental insights into coupled electrochemical processes that occur in battery materials at electronic-to-mesoscopic scales. Furthermore, representative successes of these techniques in modeling electrodes, electrolytes, and electrode-electrolyte interfaces are highlighted to establish the current state-of-the-art in the field.

25 ENERGY STORAGE↗
DOE OSTI2024

Cohesive phase-field chemo-mechanical simulations of inter- and trans- granular fractures in polycrystalline NMC cathodes via image-based 3D reconstruction

The optimal design and durable utilization of lithium-ion batteries necessitates an objective modeling approach to understand fracture and failure mechanisms. This paper presents a comprehensive chemo-mechanical modeling study focused on elucidating fracture-induced damage and degradation phenomena in the polycrystalline Li $\mathcal{x}$ Ni 0.5 Mn 0.3 Co 0.2 O 2 (NMC532) cathode. An innovative approach that utilizes image-based reconstructed 3D geometry as finite element (FE) mesh input is employed to enhance the precision in capturing the convoluted architecture and morphological features. For accurately representing the intricate crack configurations within the polycrystalline system, we adopted the cohesive phase-field fracture (CPF) model. Through the integration of advanced image-based geometry reconstruction technique and the promising CPF modeling approach, lithium (de)intercalation induced crack evolution (e.g., nucleation, propagation, branching and diverse modes including inter-/trans-(intra-) granular patterns) and the resulting chemical degradation can be precisely captured, which is also compared and validated with numerical predictions using a continuum damage model. In particular, this model predicts fracture induced degradation under varying fracture properties of grain boundaries and charging rates; the conclusion that NMC particles comprised of larger grains are predicted to have less degradation than those with smaller grains can also be drawn. This comprehensive analysis provides valuable insights into the fracture and degradation within polycrystalline NMC cathodes.

25 ENERGY STORAGE↗
DOE OSTI2025

On the Structural Origin of Fast Li-Ion Cycling in Tetragonal Bronze-Type Nb 8 W 9 O 47

Bronze and bronze-derived, mixed metal oxides are materials of growing interest for lithium-ion battery anodes due to their high-rate capabilities and the potential for high energy densities via multielectron redox. We report on the synthesis and electrochemical properties of the tetragonal tungsten bronzetype phase Nb 8 W 9 O 47 and our investigation into the structural evolution of this phase upon lithium (de)intercalation, with particular attention to how it relates to the fast-cycling capabilities. Electrochemical cycling shows Nb 8 W 9 O 47 can achieve greater than one Li + per transition metal at rates of C/2 or slower and maintains a capacity equivalent to 0.65 Li + per transition metal at a rate of 20C. Sequential Rietveld analysis of operando X-ray diffraction data reveals anisotropic changes to the unit cell parameters during discharge, accompanied by an off-centering of the transition metals within their octahedral environments. While higher capacities can be accessed below 1.2 V, cells discharged to 1.0 V exhibit a significant expansion of the unit cell volume and reduced Coulombic efficiencies. This report suggests that rigid crystal structures incapable of undergoing polyhedral rotational deformations can instead exploit displacive distortions of the transition metal redox center to enable fast Li-ion cycling with minimal atomic rearrangements.

25 ENERGY STORAGE↗
DOE OSTI2023

Asynchronous domain dynamics and equilibration in layered oxide battery cathode

To improve lithium-ion battery technology, it is essential to probe and comprehend the microscopic dynamic processes that occur in a real-world composite electrode under operating conditions. The primary and secondary particles are the structural building blocks of battery cathode electrodes. Their dynamic inconsistency has profound but not well-understood impacts. In this research, we combine operando coherent multi-crystal diffraction and optical microscopy to examine the chemical dynamics in local domains of layered oxide cathode. Our results not only pinpoint the asynchronicity of the lithium (de)intercalation at the sub-particle level, but also reveal sophisticated diffusion kinetics and reaction patterns, involving various localized processes, e.g., chemical onset, reaction front propagation, domains equilibration, particle deformation and motion. These observations shed new lights onto the activation and degradation mechanisms of state-of-the-art battery cathode materials.

25 ENERGY STORAGE↗