bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Circular Manufacturing of Next-Generation Lithium-ion Battery Cathode Materials with R2R Molten Salt Electrodeposition
Authors: Yang Heng , Anderson Tanner , Li Haifeng , Rodriguez Rodrigo , Reber Jason , Shyam Badri , Cook John B. , Busbee John
Published: February 2024

For the past few years, Xerion has been developing a roll-to-roll (R2R) molten salt electrodeposition technology (DirectPlateTM) for circular manufacturing of lithium-ion battery cathodes. Cathode materials such as LiCoO2, Li(NixMyCoz)O2, and LixMnyOz are demonstrated with good electrochemical properties. DirectPlateTM cathodes are distinctly different from conventional slurry-cast electrodes combining several notable properties: they are very dense with less than 10% porosity, free of additives (carbon and polymer binder), and their crystal orientation can be accurately controlled, enabling high-rate operation at or beyond state-of-the-art areal capacity loading (3-4 mAh/cm2). As Li+ diffusion primarily occurs through the single crystalline domains aligned vertically to the current collector, DirectPlateTM LiCoO2 cathodes delivers good electrochemical properties in a solid-state cell without the need to infiltrate electrolyte into the cathode. We further demonstrate that end-of-life DirectPlateTM cathodes can be efficiently re-lithiated and repaired with a short molten salt treatment; or they can be upcycled into another cathode material with a completely different composition. Finally, we demonstrate that the DirectPlateTM cathode can be employed as a redox membrane for direct lithium extraction from various lithium-containing solutions. Integrating the collective mineral refinement, electrode fabrication and recycling capabilities into the R2R DirectPlateTM platform enables next-generation circular battery manufacturing with much lower energy and environmental cost.
Pre-Lithiation of Silicon-Based Anode Materials: Concepts and Realization
Authors: Kolesnikov Aleksei , Profanter Laurin , Lee Ilha , Haneke Lukas , Winter Martin , Kasnatscheew Johannes
Published: February 2024

The capacity in lithium ion battery (LIB) relies on active lithium, i.e., lithium-ions and electrons, which separately shuttle between the electrodes during charge and discharge. Given state-of-the art active materials for anodes, loss of active lithium and capacity remains a major challenge during LIB operation, in particular in the first charge/discharge cycle due to electrolyte decomposition and formation of solid electrolyte interphase (SEI).

Pre-lithiation, i.e., artificial increase in active lithium amount into the battery is a promising strategy to counteract active lithium loss. Electrochemical(1) and chemical(2,3) methods of pre-lithiation can be distinguished. While electrochemical methods are based on the use of an external power source, the driving force of the chemical reaction is a negative change in the Gibb´s free energy which in the case of pre-lithiation is provided by the use of highly reactive chemical compounds (e.g. lithium-organic complex solutions or lithium metal). The use of lithium metal allows for a wide range of technological processes, including lamination of lithium foil, gas-phase deposition, application of lithium melts or suspensions containing lithium powder. In this contribution, various concepts of pre-lithiation will be discussed from experimental and up-scaling point of view on the example of Si-based anodes.

(1) Haneke, L.; Pfeiffer, F.; Bärmann, P.; Wrogemann, J.; Peschel, C.; Neumann, J.; Kux, F.; Nowak, S.; Winter, M.; Placke, T., Insights into Electrolytic Pre‐Lithiation: A Thorough Analysis Using Silicon Thin Film Anodes. Small
2022, 2206092.

(2) Adhitama, E.; Bela, M. M.; Demelash, F.; Stan, M. C.; Winter, M.; Gomez‐Martin, A.; Placke, T., On the Practical Applicability of the Li Metal‐Based Thermal Evaporation Prelithiation Technique on Si Anodes for Lithium Ion Batteries. Advanced Energy Materials
2023,
13 (3), 2203256.

(3) Bärmann, P.; Mohrhardt, M.; Frerichs, J. E.; Helling, M.; Kolesnikov, A.; Klabunde, S.; Nowak, S.; Hansen, M. R.; Winter, M.; Placke, T., Mechanistic Insights into the Pre‐Lithiation of Silicon/Graphite Negative Electrodes in “Dry State” and After Electrolyte Addition Using Passivated Lithium Metal Powder. Advanced Energy Materials
2021,
11 (25), 2100925.
(Invited) A "Master Curve" for Plating Onset, Reaction Inhomogeneity during Fast Charging: Experiment and Theory
Authors: Mijailovic Aleksandar S , Wang Guanyi , Waag-Swift Seth , Luo Mei , Lu Wenquan , Wu Qingliu , Sheldon Brian W.
Published: February 2024

Inhomogeneous intercalation in porous anodes may lead to accelerated lithium plating during fast charging. This reaction inhomogeneity can occur both at the particle level or at the length scale set by the electrode thickness. Many studies have investigated the effects of various physical and electrochemical properties (e.g., ionic and mass transport, interface reaction kinetics, electrode thermodynamic behavior) on reaction inhomogeneity. However, their effect on accelerated lithium plating at high C-rates has not been fully elucidated. In this work, theory and experiment are used to study how reaction inhomogeneity and plating are related at high C-rates. It is shown that a non-dimensional number, the “reaction inhomogeneity parameter” λ, can be used to predict plating onset in graphite half-cells with a simple analytical solution derived from porous electrode theory, so long as anode particles are sufficiently small. Experiments measuring lithium plating onset in a small-particle graphite at various C-rates and thicknesses can be normalized to a single “master curve” for plating onset when plotted as a function of λ. These comparisons validate the theoretical predictions from both analytical and numerical modeling. Further, experiments with in situ visual inspection of local intercalation in graphite demonstrate that this λ parameter can predict reaction inhomogeneity measured using various metrics. These combined results support the numerical prediction that reaction inhomogeneity on the electrode length scale is responsible for accelerated plating at high charge rates for small-particle graphite. Further, it is shown with theory that this normalization procedure may be applicable for varied porosity, tortuosity, electrolyte materials and different anode materials. Finally, it is demonstrated that use of this “master curve” can be extended to patterned electrodes where channeled architectures are used to improve high C-rate charging.
Understanding the Influences of Laser Perforation on Thick Electrodes for Lithium Ion Batteries Via 3D Microstructure Simulations
Authors: Krumbein Lukas , Hein Simon , Danner Timo , Prifling Benedikt , Neumann Matthias , Kouli Maher , Mund Malte , Schmidt Volker , Latz Arnulf
Published: February 2024

Laser perforation is a precise technique to decrease ionic diffusion limitations by selectively removing material with spatial precisions of tenth of micrometres. It is mainly applied in thick electrodes to improve foremost rate capability, as well as cycle stability, Li plating detention and wetting efficiency.[1] [2]

Mostly, holes are created in the batteries through-direction leading to a material removal of about 5%-10% of the initial load. This removal creates inhomogeneous diffusion channels especially into layers close to the current collector, as opposed to a homogeneous increase in porosity.

It is of interest to find an optimal trade-off between the competing factors of capacity loss and increase in ion conductivity due to material ablation. Optimization of structuring parameters requires intimate knowledge of electrode and material properties. However, there is a lack of an adequate description of the inhomogeneous structure and its influence on the electrochemical performance. [1]

In our presentation we show a detailed 3D microstructure resolved simulation study, examining the influencing parameters for laser perforation.

The data suggests, that perforating holes with small diameter at a short distance, which results in an ablation of ca. 8% gives generally desirable improvements for the rate capability. Laser perforation is distinctively favourable in contrast to a raise in homogenous porosity.

Moreover, the microstructure resolved simulation also allows for a detailed analysis of different hole shapes and hole misalignment in electrodes after stacking. We evaluate the impact of different configurations on the electro chemical performance. [3]

References:

[1] Dunlap et. al., JPowSour, 2022, 231464

[2] Chen et. al., JPowSour, 2020, 228475

[3] De-Lauri et. al., ACSAEM, 2021, 4, 13847-13859

Figure 1
Frequency Response Informed Order Reduction Approaches for Pseudo-2D Model for Li-Ion Batteries
Authors: Mishra Astitva , Jangale Akash Suhas , Subramanian Venkat R. , Suthar BharatKumar
Published: February 2024

To simulate the battery performance quickly using the P2D model,1,2 various simplifications and mathematical reformulations are introduced. One such simplification is the polynomial profile approximation in the solid phase. Such simplifications result in a significant reduction in the simulation time while having a minor compromise in the accuracy, especially for highly fluctuating currents. Building on the previous work by Subramanian et al.,3,4 in this presentation, the Hexic profile polynomial approximations are proposed. The frequency response-based criteria were used to derive the optimal coefficients which give rise to the best possible Hexic model for a given family of current profiles.5

Compare to the Quartic model (QP) based simplifications, the proposed Hexic model (HP) provides comparable computational time (t
sim) but offers a factor of 3 improvements in the average error in the cell voltage calculation (εavg [mV]). However, compared to the fully converged FD model, it offers significant improvement in computational time at the cost of 0.5 mV average error in the cell voltage (see Figure 1).

In the context of the P2D model, Hexic profile-based solid phase concentration treatment leads to much better prediction (compared to the parabolic and quartic profiles) of the internal variables such as current distribution in electrodes and the stress distribution (radial and tangential stresses inside the solid particles) generated during lithiation and de-lithiation process.

The presentation will also discuss critical comparison between the global polynomial-based models (orthogonal collocation and Galerkin approaches) and the frequency domain-based approaches.

References

Doyle, T. F. Fuller, and J. Newman, J Electrochem Soc, 140, 1526 (1993).

Newman and K. E. Thomas-Aleya, John Wiley & Sons, New Jersey (1991).

R. Subramanian, J. A. Ritter, and R. E. White, J Electrochem Soc, 148, E444 (2001).

R. Subramanian, V. D. Diwakar, and D. Tapriyal, J Electrochem Soc, 152, A2002 (2005).

Mishra, V. R. Subramanian and B. Suthar, J Electrochem Soc, 169 (12), 120532 (2022).

Figure 1
Simulation Study of Li-Ion Batteries Considering the Porosity and Tortuosity of Separator
Authors: Permatasari Agnesia , So Magnus , Mori Yuki , Saito Yuki , Inoue Gen
Published: February 2024

Lithium-ion batteries (Li-ion batteries) offer high energy and power densities, making them the most widely used battery technology for energy storage in various applications such as grid-scale, automotive, and electronic devices. One of the critical components of a Li-ion battery is the porous separator which can impair performance at high charge/discharge rates. Separator has a considerable influence on the transport of lithium ions. The structural properties of the separator, such as porosity and tortuosity can have a significant impact on heat generation and polarization of lithium concentration as well as the current density distribution inside the separator. The porosity of a porous separator is a well-defined feature that may be easily determined. In contrast, the tortuosity of separators, is more difficult to assess.

To model and calculate the separator properties, in this study, the simulated structural separator was constructed by numerical analysis1 based on actual separator structure from Cryo-FIB-SEM. The numerical simulation of the ion-transport model for concentrated electrolyte solutions using the model developed by Newman et al2. Different structures of separators provided different behaviors at different charge/discharge rates. To evaluate overall battery performance, using the previously reported structural information3,4, lithium nickel manganese cobalt oxides (NCM), 1.0 M LiPF6 solution in EC-DEC solvent, and graphite were used for the cathode, electrolyte, and anode, respectively.

This work simulated and compared three different separator structures: foam, non-woven fabric, and stretched structure with three different constant charging rate (C-rate) conditions (1 C, 5 C and 8 C). The calculation of porosity and tortuosity has been done for through-plane model. The higher C-rate will increase the heat generation significantly and affect the battery`s thermal behavior. The tortuosity and porosity have correlation on the effective ionic conductivity σeff = (ε/τ)*σ and effective diffusion coefficient Deff = (ε/τ)*D. Higher separator porosity can effectively increase the effective diffusion coefficient, hence improving mass transfer and reducing resistance. The separator with uniform porosity and smaller tortuosity showed smaller diffusion polarization because Li+ can be transported easily and uniformly in it, leading to lower heat generation even in high C-rate condition. The model developed in this study is intended to be valuable in understanding behavior of porous separators and optimizing the battery design.

Acknowledgement: This research was carried out under the project (Grant Number JPMJMI21G4) supported by the JST-Mirai Program, Japan.

References:

Inoue et al., J. Pow. Sour.,
175, 145 (2008).

Newman and K. Thomas-Alyea, Electrochemical Systems, 3rd ed., Wiley Interscience, Hoboken, (2004).

Inoue et al., J. Chem. Eng. Japan.,
54 (5) 207-212 (2021).

K. Ikeshita et al., ECS Trans.,
75 (20) 165-172 (2017).
Modeling of Crystal Structure in Li-Rich Layered Oxides for Rechargeable Lithium Cells
Authors: Celeste Arcangelo , Tuccillo Mariarosaria , Silvestri Laura , Brutti Sergio
Published: February 2024

Lithium-Ion Batteries (LIBs) require further development in terms of safety and performance to establish also in the automotive market and new materials at both electrode sides as well as at the electrolyte side are necessary to overcome the state of-the-art and the commercial benchmarks. [1] The positive electrode materials constitute the bottleneck for present LIBs. They are based on layered structures (LiCoO2, NMC, NMA), spinel (LiMn2O4) and olivine LiFePO4, with rather moderate specific capacities (120–180 mAhg−1). [2] Therefore, the resulting specific energies are insufficient to meet market demand. Over-stoichiometric Li-rich layered oxides (LRLOs) are a family of positive electrode materials with promising theoretical electrochemical performance. [3] Indeed, they have received widespread attention due to their extremely high specific capacity (>250 mAhg−1) and low cost. Their extraordinary capacity has been confirmed to originate not only from the redox activities of transition metals, but also from the redox activities of oxygen anions. The crystal structure of LRLOs is an open playground of debate. There are two main hypotheses: a) a two phase nano-domain and b) a single phase solid solution. In this framework, the modeling of the crystal structure is quite challenging. Usually, the description of the structure of LRLOs can be done with rhombohedral or monoclinic unit cell. Nevertheless, the use of convention unit cells leads to a bad representation of the crystal structure because of the missing of structure features in the superstructure region (20<θ<30 in typical diffraction pattern with Cu Kα). In this communication, we demonstrate that extensive defectivities play a key role in the shape and intensity of diffractograms of LRLOs. In particular, we show how the use of supercells or defects (antisite defects and stacking faults) can help in the description of crystal structure of this class of materials.

[1] Zubi, G.; Dufo-López, R.; Carvalho, M.; Pasaoglu, G. The Lithium-Ion Battery: State of the Art and Future Perspectives. Renewable and Sustainable Energy Reviews 2018, 89, 292–308.

[2] Casas-Cabanas, M.; Ponrouch, A.; Palacín, M.R. Blended Positive Electrodes for Li-Ion Batteries: From Empiricism to Rational Design. Isr J Chem 2021, 61, 26–37.

[3] Nie, L.; Chen, S.; Liu, W. Challenges and Strategies of Lithium-Rich Layered Oxides for Li-Ion Batteries. Nano Res 2022.
Bayesian Approach to Estimate Distribution of Relaxation Times for Lithium-Ion Batteries
Authors: Kim Seongyoon , Choi Jung-Il
Published: February 2024

Electrochemical impedance spectroscopy (EIS) has emerged as a powerful tool for analyzing the state of lithium-ion batteries due to its ability to provide rich electrochemical information. Traditionally, equivalent circuit and physical models have been utilized for interpreting EIS data. However, these methods possess inherent drawbacks: equivalent circuit models are non-unique, while physical models can be challenging to implement. As an alternative, the distribution of relaxation times (DRT) has garnered increasing attention in recent years. The DRT method enables the analysis of EIS data without predefining a model's shape, allowing for the decomposition of internal characteristics in complex systems, such as lithium-ion batteries. Despite its advantages, DRT estimation is an ill-posed inverse problem that often requires regularization or fine-tuning based on empirical choices, which can lead to the misinterpretation of EIS data.

To address these challenges, we propose a Bayesian approach that enables the estimation of DRT while considering uncertainties, even in the presence of observational errors in EIS data. Moreover, the proposed method can assist in estimating the state of health (SOH) of the battery, which provides valuable insights into the battery's overall performance, longevity, and safety. To validate the efficacy of our proposed method, we apply it to synthetic EIS data and compare its performance with existing DRT estimation methods. The results show that the proposed Bayesian approach offers a more robust and accurate estimation of DRT. We also demonstrate the practical applicability of the proposed method by applying it to real lithium-ion battery EIS experimental data, where it successfully extracts meaningful information about the battery's internal state and SOH. In summary, the proposed DRT-based Bayesian method has the potential to enable a robust diagnosis of the internal state and SOH of lithium-ion batteries through EIS measurements. By incorporating this approach, researchers and industry practitioners can gain a deeper understanding of battery performance, facilitating the development of improved diagnostic techniques and battery management strategies to enhance the performance and reliability of lithium-ion batteries. This, in turn, could contribute to the broader adoption of sustainable energy solutions, such as electric vehicles and renewable energy storage systems.

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grants funded by the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20214910100070).

Figure 1
Ageing and Post-Mortem Study of LNMO-Based Lithium Ion Battery Pouch Cells
Authors: Schmitt Christina , Maximillian Davin , Sotta Dane , Martin Agathe , Debruyne Cédric , Reynier Yvan , Buga Mihaela , Ungureanu Cosmin , Kopljar Dennis , Friedrich K. Andreas
Published: February 2024

Lithium ion batteries are nowadays widely employed in a variety of applications from consumer electronics to electric vehicles. Due to the rising demand for batteries, more affordable and sustainable batteries are needed that exhibit at the same time high energy densities, high power capabilities, long cycle life, and increased safety. One concept to meet these requirements is to develop cobalt-free cathode materials of which the high-voltage spinel LNMO (LiNi0.5Mn1.5O4) is a promising material due to its high energy density and high operating voltage of 4.7 V. However, the high operating voltage has also its drawbacks. Commonly used carbonate-based electrolytes oxidize at high voltages, leading to the continuous formation of a cathode-electrolyte interface (CEI). Additionally, LNMO is prone to transition metal dissolution which not only leads to a reduced stability of the cathode active material but due to migration and deposition of the transition metals on the anode surface also to an altered solid electrolyte interface (SEI) formation and significant impedance rise of the anode.1 Both ageing mechanisms provoke increased lithium loss and high resistances and thus a poor cycling performance.2, 3

In the Horizon 2020 LC-BAT5 project HYDRA, LNMO-based prototype pouch cells are developed and built. Herein, we want to present the results from the comprehensive analysis of their performance and cycling behavior. The influence of upper cut-off voltage, charge and discharge current rate as well as temperature on the degradation are thoroughly investigated by electrochemical methods such as differential voltage analysis and impedance spectroscopy. After cycling, selected cells are opened under argon atmosphere followed by electrochemical characterization as well as physical analysis such as SEM-EDX and XPS in order to get further insights into the underlying ageing mechanisms. We thereby reveal the main degradation mechanisms as a function of the cycling conditions and derive solutions on how to increase the cycle life.

1. C. Zhan, T. Wu, J. Lu and K. Amine, Energy Environ. Sci.,11 (2), 243-257 (2018).

2. J. Ma, P. Hu, G. Cui and L. Chen, Chem. Mater.,28 (11), 3578-3606 (2016).

3. W. Li, Y.-G. Cho, W. Yao, Y. Li, A. Cronk, R. Shimizu, M. A. Schroeder, Y. Fu, F. Zou, V. Battaglia, A. Manthiram, M. Zhang and Y. S. Meng, J. Power Sources,473, (2020).

Pseudo-OCV (a) and differential voltage analysis curves (b) of LNMO-graphite pouch cell cycled with 0.3C CCCV charge and 0.1C discharge at 25°C

Figure 1
Ultrasound Spectroscopy of Lithium-Ion Batteries: Insights into Layering Distances
Authors: Feiler Simon , Daubinger Philip , Gold Lukas , Hartmann Sarah , Giffin Guinevere A.
Published: February 2024

Improving diagnostics of lithium-ion batteries (LIBs), and in particular the measurement and prediction of the remaining capacity, can lead to a longer lifetime and safer use. One promising approach to LIB diagnostics is the use of ultrasound. Ultrasound signals can measure stiffness changes of the active materials occurring during cycling and aging and can be used to predict state-of-charge (SoC) and state-of-health (SoH) of the cells [1,2]. Traditionally, ultrasound signals have been analyzed in the time domain by studying the time of flight. However, a novel approach is to study the signals in the frequency domain.

The aim of this study was to investigate the potential of ultrasound spectroscopy to provide insights into the layering distances, sound velocity of the layer constituents, and homogeneity of layer thickness of LIBs. A key consideration in analyzing ultrasound signals is the interference effect resulting from reflections at different layer interfaces in the battery. The most relevant reflections occur at the copper and aluminum current collectors, so one unit of (Copper-Anode-Separator-Cathode-Aluminum) can be considered as the basic resonator. In transmission, the first destructive interference (Antiresonance) occurs when the width of the resonator is a quarter of the wavelength, which results in a dip in the frequency response. The frequency of the dip can be found by sweeping the measurement frequency (i.e., ultrasound spectroscopy) and can providing insights into the resonator width and therefore layering distances.

This work presents a study of a commercial LIB (nickel-rich NCM/Graphite) with a nominal capacity of 12 Ah from Kokam (SLPB065070180, Kokam Co., Ltd.) using ultrasound spectroscopy. The results exhibited an antiresonance at 2.26 MHz in the commercial LIB (Figure 1). This frequency and sound velocity (measured to be 1640m/s) were then used to calculate the wavelength at 726 µm, and the resonator width was calculated to be 726 µm/4 = 181 µm. This result is in good agreement with the measured width of one unit from post mortem analysis at ~187 µm. The changes in the antiresonance were then studied over the course of 1000 cycles.

References

[1] A.G. Hsieh, S. Bhadra, B.J. Hertzberg, P.J. Gjeltema, A. Goy, J.W. Fleischer, D.A. Steingart, Electrochemical-acoustic time of flight: in operando correlation of physical dynamics with battery charge and health, Energy Environ. Sci. 8 (2015) 1569–1577. https://doi.org/10.1039/C5EE00111K.

[2] Feiler, S., Daubinger, P., Gold, L., Hartmann, S., Giffin, G. A., Interplay between Elastic and Electrochemical Properties during Active Material Transitions and Aging of a Lithium-Ion Battery, Batteries & Supercaps 2023, 6, e202200518., https://doi.org/10.1002/batt.202200518

Figure 1
(Invited) High-Nickel Layered Oxide Cathodes: Crack Vs. Surface Reactivity
Authors: Manthiram Arumugam
Published: February 2024

The appetite for long driving range and high energy density is pushing the nickel content in layered oxide cathodes for lithium-ion batteries. The lying of Ni3+/4+:3d band slightly above the Co3+/4+:3d band enables to extract more lithium during charge without encountering oxygen release from the lattice in high-nickel cathodes compared to that in LiCoO2. However, as the nickel content increases in the lattice, the cells suffer from cycle and thermal instability. The cycle instability has largely been attributed in the literature to the formation of cracks caused by the occurrence of H2-H3 phase transition with large lattice parameter changes during high degree of charge. Several approaches, such as doping with other cations and microstructural control of the primary and secondary particles, have been extensively pursued to overcome the challenges and improve the cycle life.

With a systematic investigation of a number of cathode compositions and their characterization after extensive cycling, this presentation will illustrate that surface reactivity of high-nickel cathodes with electrolyte plays a dominant and decisive role on cycle life. Even cathodes like LiNiO2 with 100% Ni without any cation doping or surface coating could be cycled with high capacities over a large number of cycles with an appropriate choice of electrolyte that suppresses surface reactivity. Electrolytes that are stable to slightly higher voltages, even by as low as 100 mV, compared to the conventional electrolytes alter the surface reconstruction pathway on cathode surface in contact with electrolyte. Electrolytes with better high-voltage stability favor the formation of mildly reduced LiNi2O4 spinel on the surface without much oxygen release from the surface. In contrast, electrolytes that have inferior stability to higher voltages lead to a drastic reduction of the cathode surface to highly reduced Ni3O4 spinel and NiO rock salt phases with significant oxygen loss from and volume change on the surface, which could cause crack initiation on the surface, followed by their propagation into the bulk. Interestingly, the fast 3-dimensional lithium-ion and electron transport in spinel LiNi2O4 supports a facile charge transfer through the cathode-electrolyte interphase (CEI), resulting in better cycle life, in contrast to the poor lithium-ion transport in both spinel Ni3O4 and rock salt NiO phases, resulting in poor charge-transfer through the CEI and inferior cycle life. With robust electrolyte formulations with better high-voltage stability, long cycle life could be achieved even with the repeated occurrence of the H2-H3 phase transitions over a large number of cycles.
Entropic Stabilization in Lithium Rich Transition Metal Oxide Cathodes
Authors: Burke Sven Anders , Meng Shirley
Published: February 2024

It is well known that lithium rich transition metal oxide cathodes (LRM) experience voltage fade and capacity loss over the course of cycling, and it is generally known that these are a result of the LRM materials’ general instability 1–7. However, the mechanisms behind these losses are still unknown, due in large part to the structural ambiguity and controversy associated with the LRM material structure. In this perspective we consider the role entropy plays in LRM materials’ structural stability and electrochemical properties. With this mind set we argue that due to their metastability LRM cathodes’ structure and properties are not synthesis agnostic, and therefore establishment of consistent synthetic procedures is of paramount importance. We also propose that LRM materials could be categorized as entropically stabilized oxides through exploring their configurational entropies, phase behaviors, and thermal responses. The entropic stabilization of LRM materials is also found to be consistent with the ordering behaviors of LRM cathode transitional metal layers, with this ordering presenting both compositional, thermal, and electrochemical dependencies. The impact of these behaviors on the redox and electrochemical structure and activation of LRM materials is also explored. Finally, we seek to put these findings into the context of the wider battery field.

Fell, C. R. et al. Correlation Between Oxygen Vacancy, Microstrain, and Cation Distribution in Lithium-Excess Layered Oxides During the First Electrochemical Cycle. Chem. Mater. 1621–1629 (2013) doi:10.1021/cm4000119.

Lu, Z., Beaulieu, L. Y., Donaberger, R. A., Thomas, C. L. & Dahn, J. R. Synthesis, Structure, and Electrochemical Behavior of Li [Ni x Li(1/2-2x/3) Mn(2/3-x/3)]O2. J. Electrochem. Soc.
149, A778–A791 (2002).

Wu, Y. & Manthiram, A. High Capacity, Surface-Modified Layered Li†Li„1−x.../3Mn„2−x.../3Nix/3Cox/3‡O2 Cathodes with Low Irreversible Capacity Loss. Electrochem. Solid-State Lett.
9, A221–A224 (2006).

Dupré, N., Cuisinier, M., Legall, E., War, D. & Guyomard, D. Contribution of the oxygen extracted from overlithiated layered oxides at high potential to the formation of the interphase. J. Power Sources
299, 231–240 (2015).

Jarvis, K. A. et al. Formation and effect of orientation domains in layered oxide cathodes of lithium-ion batteries. Acta Mater.
108, 264–270 (2016).

Jiang, M., Key, B., Meng, Y. S. & Grey, C. P. Electrochemical and Structural Study of the Layered, ‘Li-Excess’; Lithium-Ion Battery Electrode Material Li[Li 1/9 Ni 1/3 Mn 5/9 ]O 2. Chem. Mater.
21, 2733–2745 (2009).

Hy, S. et al. Performance and design considerations for lithium excess layered oxide positive electrode materials for lithium ion batteries. Energy Environ. Sci.
9, 1931–1954 (2016).
Multiscale Probing and Redesign of the Solid-State Synthesis Toward Defect-Free Ni-Rich Layered Cathodes
Authors: Park Hyeokjun , Jin Hyeongmin , Kim Hyungsub
Published: February 2024

Nickel-rich lithium layered oxides (LiNixCoyMnzO2, NCM, x+y+z=1, x≥0.6)) have received tremendous attention as the most promising cathode materials for the practical development of high-energy lithium-ion batteries. However, they commonly suffer from rapid capacity decay along with structural and morphological degradation. Previous studies have unraveled that the general failure mechanism involves the mechanical deterioration of electrode particles, originating from micro-cracking in particles due to the build-up of significant anisotropic strains during phase transition and the chemical parasitic reactions with electrolytes through the crevice created. Such chemo-mechanical failures are triggered and aggravated by various structural defects, including internal void spaces, surface reconstruction layers, and intragranular nanopores, typical features of the conventionally synthesized nickel-rich layered oxide materials. It remains elusive how these defects are formed regardless of the use of single-crystalline or polycrystalline particles. A fundamental understanding of the general defect formations is thus indispensable to clarify how the synthesis process induces the formation of intrinsic defects from the precursor to the final product stage and how these defects affect the electrochemical degradation at the primary- and secondary-particle levels. Critical questions that require in-depth study include how the spatially inhomogeneous solid-state reaction begins at the interface of reacting precursors, propagates during the synthesis, and triggers the generation of defects. In this presentation, I will show the hidden synthetic mechanism of nickel-rich layered oxide materials using a combination of high-end and multi-length-scale analysis methods, including aberration-corrected TEM, in situ heating TEM with gas control, and in situ XRD. The kinetic interplay in synthesis of nickel-rich lithium layered oxide and its implications will be discussed in detail. Furthermore, the microstructural pore defects of NCN9235 during the heating process were quantitatively characterized. Based on our mechanistic understanding, we propose a redesign of solid-state synthesis pathway to achieve structurally integrated nickel-rich layered oxide cathodes.
(Invited) Effects of LiPF6 Salt Concentration on the Cycling Performance of NMC532 Cell Containing Organic Carbonate Solvents
Authors: Wu She-huang , Lee Po-Han
Published: February 2024

Pouch-type cells with NMC532 cathode, MCMB anode (A/C loading ratio of 1.1) and electrolytes containing various LiPF6 concentrations in EC/EMC (3:7 by volume) + 2wt% VC were prepared for investigating the effects of lithium salt concentration on the cycling performance of NMC532 cells. These cells were cycled at 0.5 C rate within 3.0 and 4.2 V until their residual capacity become lower than 70% of their initial capacities, respectively, as shown in Figure 1. After end of life, these cells were disassembled for post-mortem study. The cycled electrodes were used to assemble into coin-type cells with lithium metal for estimating their losses of lithium inventory (LLI), losses of cathode material (LAMC) and losses of anode material (LAMA) by comparing their specific capacities of first and second cycles of the coin-cells with those of the coin-cells prepared with fresh electrodes, respectively. XRD, SEM, HRTEM and XPS were also used to reveal the phase evolution, structure and morphology changes of the electrode materials after cycling. Results suggest that the fast capacity fade of the cell prepared with the electrolyte containing 1 M LiPF6 salt concentration can be attributed to the carbonate solvent oxidation via dehydrogenation on the cathode surface at voltages higher than 3.8 V as reported by Zhang et al.(1) The oxidation can not only accelerate the increase of impedances at anode side, the losses of lithium inventory and anode material by the SEI formation from the reactions between the oxidation products and lithium ions, but also cause the loss of cathode active material and resistance growth at the cathode side, though they are less significant. They can be caused by the phase evolution of spinel and rock-salt phases on the surface of cathode particles, which had been observed from the HRTEM and SAD studies of the cathode particle collected from the cycled cell prepared with 1 M LiPF6 in EC/EMC electrolyte after 600 cycles. It was also found that the amounts of spinel and rock-salt phases formed on the NMC particle surface, rates of capacity fading and resistance growth of the aged cells decreased with the increased LiPF6 salt concentration contained in the electrolytes of the cells. It can be due to the higher salt concentration can induce the less free solvent for being oxidized on the cathode particle surface at voltages higher than 3.8 V. Whereas the layered NMC phase only can be found on the surface of NMC particle collected from the cathode of the cycled cell prepared with 3 M LiPF6 electrolyte after 1100 cycles. This cell shows lower LLI, LAMC, LAMA and impedances growth after 1100 cycles than those of the cell with electrolyte of 1 M concentration after 600 cycles.

Reference:

Zhang, Y. Katayama, R. Tatara, L. Giordano, Y. Yu, D. Fraggedakis, J. G. Sun, F. Maglia, R. Jung, M. Z. Bazant and Yang Shao-Horn, Energy Environ. Sci., 2020, 13, 183-199.
Optimizing the Potential Diagram for a Highly Sustainable and High-Energy-Density SiOx/LiNi0.5Mn1.5O4 Battery
Authors: Ko Seongjae , Han Xiao , Shimada Tatau , Takenaka Norio , Yamada Yuki , Yamada Atsuo
Published: February 2024

In the transition towards a sustainable society, developoing a battery system that meets various social requirements, such as high energy density, cost-effectiveness, environmental sustainability, and elemental abundance, is urgent. Elminating cobalt (Co) from cathodes due to its economically/geopolitically constrained supply chain and child labor issues is particularly important.1 In this regard, considerable efforts have been conducted in the past decade to realize an ideal full cell combined with a high-capacity and earth-abundant SiOx anode (theoretically 1965~4200 mAh g-1 with 2≥x≥0 at ≤0.4 V vs. Li/Li+) and a high-potential Co-free spinel LiNi0.5Mn1.5O4 cathode (theoretically 147 mAh g-1 with an average operating potential of 4.7 vs. Li/Li+).2 However, its stable cycling has rarely been achieved because the reaction potentials of SiOx and LiNi0.5Mn1.5O4 are located outside the operating potential windows of traditional electrolytes, thus giving rise to severe electrolyte decomposition at both anodes and cathodes.

Herein, we report a long-awaited extremely stable SiOx/LiNi0.5Mn1.5O4 battery over 1000 cycles with an upper cut-off voltage of 4.9 V by carefully optimizing its overall potential diagram with a specifically designed electrolyte, 3.4 mol L-1 (M) LiN(SO2F)2/methyl (2,2,2-trifluoroethyl) carbonate (LiFSI/FEMC).3 The developed electrolyte provides remarkably high redox stabilities by: 1) destabilizing Li+ in the electrolyte4, which is a key to reducing the thermodynamic driving force of electrolyte reduction with an upshift of the reaction potential of the SiOx; 2) offering a large amount of anions with modified electronic states5, which enables the formation of a highly Li+-conductive and chemically/electrochemically stable anion-derived SEI at the negatively charged SiOx surface; and 3) increasing the oxidation potential of the electrolyte while retarding Al and trasition metal dissolution, thus guranteeing the high reversibility of the LiNi0.5Mn1.5O4. We belived that the electrolyte-design rationale highlighted in this work will provide a new chance to develop and design highly sustainable high-energy-density Li-ion batteries.

Reference

Olivetti, E. A., Ceder, G., Gaustad, G. G. & Fu, X. Joule 1, 229–243 (2017), Banza Lubaba Nkulu, C. et al. Nat. Sustain. 1, 495–504 (2018), Lee, S. & Manthiram, A. ACS Energy Lett. 7, 3058–3063 (2022).

Liu, Z. et al. Chem. Soc. Rev. 48, 285–309 (2019), Fan, X. & Wang, C. Chem. Soc. Rev. 50, 10486–10566 (2021).

Ko, S., Han, X., Shimada, T., Takenaka, N., Yamada, Y. & Yamada, A. doi:10.21203/rs.3.rs-2536539/v1 (2023).

Takenaka, N., Ko, S., Kitada, A. & Yamada, A. doi:10.21203/rs.3.rs-1830373/v1 (2022).

Sodeyama, K., Yamada, Y., Aikawa, K., Yamada, A. & Tateyama, Y. J. Phys. Chem. C 118, 14091–14097 (2014).
Improving Extreme Temperature and Charge Rate Performance in Li-Ion Batteries through Addition of Fluorinated Electrolyte Additives
Authors: Kerber Brian M , Guillot Sarah Lucienne , Du Peng , Zhou Liu (Amy) , Garg Shipra , Usrey Monica Lee
Published: February 2024

Despite advances in Li-ion battery electrolytes, commercial electrolytes continue to include organic solvents that are unable to withstand many of the arduous conditions demanded by the industry today, such as extreme temperatures and charge rates. The stability limits of these solvents damper the advancement of Li-ion batteries needed to sustain automotive electrification and other industrial applications. Further efforts are needed to enable electrolyte formulations to withstand the operational demands of Li-ion batteries in the market today.

Koura has developed a series of fluorinated materials for use in lithium-ion electrolytes that demonstrate improved stability and safety over conventional commercial electrolytes. In a recently completed study, the impact of Koura’s fluorinated solvents on performance in 4.3V Gr/NMC811 was examined, with a particular focus on benefits seen on extreme temperature and rate performance. Testing included cycling and rate performance across a range of temperatures from -20 °C to 45 °C and cycling conditions from C/2 to 4C. It has been found that these materials exhibit improved performance in low temperature testing, as well as reduced gassing and increased performance in high-temperature and fast charge cycling. To investigate the mechanisms responsible for the observed improvements, comprehensive post-test analysis has been conducted, including gas identification and quantification via gas chromatography, bulk electrolyte composition analysis via NMR spectroscopy, and surface layer characterization via XPS and SEM. Bulk properties of the materials and electrolytes are correlated to performance benefits where appropriate.

This presentation will summarize Koura’s efforts to fill a major gap in the demands of the battery industry today through the development of fluorinated electrolyte materials. Specifically, we will present data highlighting the performance of fluorinated compounds on improving battery performance under strenuous conditions with respect to both temperature and cycling rate. Results from post-test analyses will be discussed highlighting the mechanisms underlying the observed performance improvements.
Nonflammable Fluorinated Ester-Based Electrolytes for High Voltage Li Batteries with LiCoO2 Positive Electrode
Authors: Ugata Yosuke , Yukishita Kazuki , Yabuuchi Naoaki
Published: February 2024

LiCoO2 is widely used as a positive electrode material for LIBs. The theoretical capacity of LiCoO2 is calculated to be 274 mA h g–1 upon full delithiation, but the practical reversible capacity is generally restricted to approximately 140 mA h g–1 to avoid capacity deterioration when cycled at higher voltages (>4.2 V vs Li/Li+). To solve this limitation, functional electrolytes that possess a high oxidative stability and form a stable and effective passivation layer on the LiCoO2, are desired.

In this study, we report that the cyclability of LiCoO2 under high-voltage operation is drastically improved by using a fluorinated ester, methyl 3,3,3-trifluoropropionate (MTFP), as an electrolyte solvent.1 Notably, the combined use of MTFP-based electrolyte and mixed sodium carboxymethyl cellulose/styrene-butadiene rubber binder synergistically stabilize the LiCoO2 electrode surface, resulting in the almost no capacity fading for 50 cycles even with the upper cutoff voltage of 4.5 V. Note that, in general, LiCoO2 shows significant capacity deterioration when cycled at higher voltages over 4.2 V vs Li/Li+. Moreover, our study reveals that superior low-temperature performance and higher thermal stability is evidenced for the LiCoO2 with MTFP-based electrolyte when compared with that with conventional electrolyte. XPS analysis reveals that thinner and uniform passivation layer derived from PF6
– anion and MTFP is formed on the LiCoO2 electrode surface, which is the origin for improved cyclability and thermal stability of high-voltage LiCoO2 with MTFP-based electrolyte.

Reference

[1] Y. Ugata et al., and N. Yabuuchi, Chemistry of Materials, in press.
Structural and Dynamical Insights of Cu-Coordinated Cellulose Nanofibers for Li+ Battery by NMR Spectroscopy
Authors: Garaga Mounesha N , Xu Lin , Hu Liangbing , Greenbaum Steve G
Published: February 2024

In the quest of novel sustainable research to meet the global surge of clean energy demand, cellulose nanofibers (CNF) derived from natural wood materials offer exceptional properties for safe, cost-effective, efficient Li+ batteries. A new strategy has been established via introducing Cu2+ into the CNF to achieve a greater mobility of Li+, where Cu2+ opens up one-dimensional nanofibrils and creates molecular channels.1 Various experimental methods and molecular dynamic simulations have been used to characterize these materials. In this context, Nuclear Magnetic Resonance (NMR), a highly sensitive technique plays a significant role in providing new insights into the structure and dynamics of Li-Cu-CNF materials. In collaboration with Prof. Liangbing Hu, University of Maryland, current research focusses on studying highly conductive Li-Cu-CNF materials prepared with different Li-salt via different synthetic approaches in the ARPA-E project. Fast magic angle spinning (MAS) detecting 1H helps in estimating the residual solvent/H2O present in Li-Cu-CNF materials, which is crucial to determine the Li+ transport mechanism. Pulsed Field Gradient (PFG) NMR has been used to measure the diffusivity of Li+ and anion and to estimate the Li+ transference number (t
Li+). We found that the estimated t
Li+ of studied Li-Cu-CNF materials is much greater as compared to the other polymer-based electrolytes. Additionally, the anisotropic diffusion of Li+ and anion in aligned cellulose wood materials have been well-established through PFG NMR. Lastly, the local structure of cellulose fibers and their spatial interactions with ionic species are probed through multi-dimensional (1D and 2D) solid state NMR detecting 1H, 7Li, 19F, 13C nuclei.

Reference.

Yang, Q. Wu, W. Xie, X. Zhang, A. Brozena, J. Zheng, M. N. Garaga, B. H. Ko, Y. Mao, S. He, Y. Gao, P. Wang, M. Tyagi, F. Jiao, R. Briber, P. Albertus, C. Wang, S. Greenbaum, Y.-Y. Hu, A. Isogai, M. Winter, K. Xu, Y. Qi, and L. Hu, Copper-coordinated cellulose ion conductors for solid-state batteries. Nature (2021) 598, 590–596.