bluuebunny/crossref_metadata_2025 huggingface dataset:
Nb-Based Oxides As High Power Negative Electrode Materials
Authors: Crosnier Olivier , Le Calvez Etienne , Dupre Nicolas , Dunn Bruce S. , Brousse Thierry
Published: February 2024

Today, one of the main challenges of lithium-ion batteries is to have the ability to charge faster and to provide high power during longer periods, thus allowing a larger development of intermittent electric power sources [1]. The actual negative electrode materials (graphite and silicon mainly) cannot sustain such high rate capabilities. In this work, we are therefore investigated some materials of the plentiful family of niobium-based oxides. A presentation of old and interesting structures will be briefly reviewed. As an example, the case of KTiNbO5 will be discussed and proposed as efficient negative electrode materials for next generation of lithium ion batteries.

The layered KTiNbO5 with a two-dimensional framework represents a playground to produce a large range of closely related phases.[2] The protonated HTiNbO5 analogue is obtained by ion exchange in acidic solution and it preserves a layered structure with a smaller interlayer distance. After dehydration of HTiNbO5 at 400°C, the so-obtained Ti2Nb2O9 phase displays a 2D arrangement with empty channels unlike tunnels of H(K)TiNbO5.

In this work, all the synthesized phases were studied as negative electrode materials in lithium-ion batteries. Tested in 1M LiPF6 in EC/DMC between 1.0V and 3.0V vs Li/Li+, these phases have shown different electrochemical behaviors. When HTiNbO5 exhibits a typical plateau during the charge/discharge experiment corresponding to a biphasic phenomenon, lithiation of Ti2Nb2O9 is governed by a solid—solution mechanism. For a better understanding of the charge storage mechanism, we have combined electrochemical experiments with in situ XRD measurements. We have shown that multielectron redox and corner/edge sharing system of Ti/Nb octaedra are at the origin of an interesting capacity of more than 100 mAh.g-1 at a rate of 0.2 A.g-1. A good observed cyclability (< 500 cycles) is in accordance with in situ XRD results showing a reversible behavior of the structure during cycling. Another synthesis method, using Chimie Douce techniques, leads to nanoparticules for both HTiNbO5 and Ti2Nb2O9 and allows an increase of the electrochemical performance of these materials.

References :

[1] Choi, C. et al, Nature Rev. Mat. 5, 5-19 (2020).

[2] A. D. Wadsley, Acta Cryst. 623, 17-41 (1964).
Understanding the Thermal Stability of Li-Rich Disordered Rock-Salt Oxyfluorides
Authors: Sunariwal Neelam , Cabana Jordi
Published: February 2024

Li-rich disordered rock-salt oxyfluorides (DRS) are a new class of cathode material with unprecedented electrochemical properties. [1,2] DRS materials have already gained popularity by showing high reversible discharge capacity by substituting oxygen (O) with fluorine (F). They are a possible candidate of cathode materials for future high-energy Li-ion batteries with high capacity. Although DRS materials are explored widely for their structure and electrochemical performance, very little is known about their thermal stability. DRS oxyfluorides can be synthesized via solid state and mechanochemical ball milling. [3-5] The solid-state synthesis method is limited because of less fluorine solubility than the mechanochemical ball milling method; however, mechanochemical ball milling produces metastable materials. Few reports utilized thermal treatment on DRS to obtain structural stability and better capacity retention than the pristine DRS. [5,6] The in-depth understanding of the inherent stability of the DRS materials on thermal treatment remains poorly understood. [7] To address this gap, we investigated the thermal stabilities of Li2MO2F stoichiometries with a variety of M (M= Mn, Ni, and Co) and defined the structural transformations at different temperatures, from changes in the local structure of the oxyfluoride to decomposition into other phases, using X-ray diffraction, NMR and X-ray absorption spectroscopy. In this presentation, we will show how thermal treatments affect chemical and structural features by utilizing unique spectral characteristics. Additionally, we will discuss a complete understanding of these thermally treated F-rich phases' better electrochemical performance and capacity retention as battery cathode materials.

References:

D. A. Kitchaev et al., Energy Environ. Sci., 11, 2159–2171 (2018).

D. Chen, J. Ahn, and G. Chen, ACS Energy Lett., 6, 1358–1376 (2021).

X. Xu et al., J. Electrochem. Soc., 168, 080521 (2021).

Y. S. Moghadam, A. E. Kharbachi, G. Melinte, T. Diemant, and M. Fichtner, J. Electrochem. Soc., 169, 120514 (2022).

I. Blumenhofer et al., ACS Mater. Au (2022) https://doi.org/10.1021/acsmaterialsau.2c00064.

J. Huang et al., Small Structures, 4, 2200343 (2023).

H. Ji et al., Chem. Mater., 31, 2431–2442 (2019).
Does Anisotropic ‘Lattice’ Collapse Always Lead to Cracking in Ni-Rich Layered Oxide Cathode Particles?
Authors: S. Menon Ashok , Shah Nickil , A. Gott James , Fiamegkou Eleni , J. W. Ogley Matthew , Paez Fajardo Galo , Vaenas Naoum , Ellis Ieuan , Malliband Paul , Walker David , West Geoff , Loveridge Melanie J , Piper Louis F. , Bree Gerard
Published: February 2024

Single-crystalline Ni-rich layered oxides (LiNi
x
Mn
y
Co1−x−y
O2; x ≥ 0.8) are promising high-energy-density cathodes for future Li-ion batteries as they can withstand cathode particle cracking, which is a significant contributor to electrochemical capacity loss. The absence of grain/particle boundaries substantially mitigates the build-up of bulk structural strain in these materials generated from the anisotropic structural evolution (i.e., lattice collapse) during electrochemical cycling. However, compared to their polycrystalline counterparts, rigorous evaluations of their long-term electrochemical performance and their dependence on electrode structure changes, impedance, and particle cracking, are still necessary to take it towards commercialisation. Operando X-ray diffraction (XRD) and absorption spectroscopy (XAS) are ideal probes of these bulk electrode structure properties and provide a direct temporal correlation between the battery electrochemistry and the non-equilibrium structural changes in the electrodes. However, such studies often use electrochemically compromised cells modified for X-ray transmission that are neither representative of a real-world full-cell architecture nor operable long-term under industrially relevant cycling conditions, thereby compromising the results' practicality. This is especially problematic for technologically mature cathodes like single-crystalline Ni-rich layered oxides, which require greater scrutiny of their long-term degradation modes after hundreds of cycles. In this work, using in-house operando X-ray studies and large-area post-mortem electron tomography of a (TRL-5) pilot-line-built A7 pouch full cells with industry-relevant specifications, we demonstrate how single-crystalline LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes can withstand the severe anisotropic structural evolution and show no particle cracking even when cycled under harsh conditions of 2.5–4.4 V at 40 °C for 100 cycles. The bulk structural changes in both electrodes as well as the associated electrochemical performance loss are also evaluated. Furthermore, the validity of the in-house pilot line cell results is benchmarked against a commercially sourced Li-ion cell. In addition to furthering our understanding of single-crystalline Ni-rich cathodes, this work emphasises the need for real-world-relevant reproducible fundamental investigations of academic Li-ion cells and presents a methodology for doing so.

Figure 1
Sustainable SiO2 Nanostructures from Different Diatom Species As Anode Material for Future Generation Lithium-Ion Batteries
Authors: Thangaian Kesavan , Aga Karlsen Jon Tobias , Hua Weicheng , Svensson Ann Mari , Blanco Maria Valeria
Published: February 2024

Energy harvesting and storage devices occupy a more prominent place in the 21st century than at any time in the past. Intensive efforts have been devoted to next-generation energy storage devices such as rechargeable lithium-ion batteries (LIBs) to develop high energy density and long cycle life electrode materials from sustainable sources. In the present anode, graphite is severely restricted by capacity and unavoidable solid electrolyte interface (SEI) formation. Besides, it has been listed as a critical material by the European Commission. Recently, silicon-based electrodes have been pinpointed as promising anode candidates due to their high theoretical capacity (~4200 mAhg-1 for Li4.4Si), low operating voltage (0.4V/Li/Li+), abundant resources, and environmental friendliness. Interestingly, nanostructures of Silica (SiO2) can be extracted from the frustules (exoskeletons) of a type of microalgae called diatoms. In this current work, SiO2 frustules were grown from two different diatom species, constituting a sustainable source for producing nanostructured Si-based materials. Scanning electron microscopy (SEM) images confirmed the highly nanoporous structure of diatom silica, which was retained even after ball-milling. The electrochemical performance of SiO2 was investigated as an anode material for LIBs. Herein, we have tested both species A & B milled and un-milled samples (denoted as SPAUM, SPAM, SPBUM, and SPBM). The diatom SiO2 un-milled species A (SPAUM) exhibited a high specific capacity of ~ 810 mAhg-1 with remarkable capacity retention and coulombic efficiency even after 100 cycles at 0.1 Ag-1 and delivered a high specific capacity of ~ 400 mAhg-1 even at high current density 3 Ag-1. For comparison and understanding, commercially available diatomaceous earth milled, and un-milled silica (denoted as EDAM & EDAUM) has been subjected to the same cycling protocol. Results clearly showed species A & B milled and un-milled displaying better electrochemical performance than diatomaceous earth milled and un-milled silica. Such improved electrochemical properties like cycle life, and rate capability of SPAUM are mainly ascribed to their highly porous nature which significantly facilitates fast Li ion diffusion, its unique morphology, which favors a faster kinetics and its complete lithiation/de-lithiation after the initial activation cycle. In view of the superior electrochemical properties, such sustainably sourced SiO2 materials can be considered a potential anode material for future LIBs.

Figure 1
Increasing Battery Performance with Ohmic Drop Compensation for an Electric Drone
Authors: Magne Tang Nicolas , Decaux Celine , Thivel Pierre Xavier , Lefrou Christine
Published: February 2024

Lithium-ion batteries are now widely used in a wide variety of applications ranging from powering mobile equipment to electric vehicles (EV), through stationary electrical energy storage systems or the electrification of flying devices such as drones. The main reason for the rapid growth of this type of batteries in the market is their high specific energy (Wh/kg) and/or specific power density (W/kg) compared to older chemistries. In the case of drones, weight optimization requires that the battery not be oversized for the mission it must perform.. Moreover, batteries can be subjected to deep discharges and high currents during the mission. One of the phenomena that leads to a drop in energy at high power is the ohmic drop phenomenon. Thus a ohmic drop compensation method has been applied to the discharge of lithium batteries. In this study, four different types of NMC Li-ion batteries (18650 type) were compared; two cells typed "energy" and two cells typed "power". We have shown that the ohmic drop compensation method applied to the discharge is capable for one of the "energy" cells of greatly increasing its available capacity at high power: 21% at 4C.

A simplified electric Vertical Take-Off and Landing (e-VTOL) mission profile was applied to this energy cell. We have demonstrated, without a doubt, the interest of using this type of protocol in this case. This ohmic drop compensation method makes it possible either to extend the duration of the flight without increasing the embedded capacity of the battery (about 50% time as shown in figure 1), or to consider an emergency diversion scenario. Finally, a preliminary aging study was also carried out for this cell: the use of ohmic drop compensation has no effect on the decrease in low power performance during aging and a moderate impact on the performance at high power.

Figure 1
Improving Gas Diffusion Electrodes for Electrochemical CO2 Reduction: Influence of the Ionomer
Authors: Ubbenjans Vera , Bothe Jannik , Keller Robert , Wessling Matthias
Published: February 2024

Electrochemical CO2 reduction is a promising way of harnessing greenhouse gas as an abundant resource for the production of value-added hydrocarbons. By employing copper as the catalyst, CO2 can be converted to multi-carbon compounds such as ethylene. Highly porous gas diffusion electrodes (GDEs) enable efficient contacting of gaseous CO2 and the electrolyte. Copper-coated GDEs are commonly manufactured by depositing a mixture of copper nanoparticles and ionomer on a gas diffusion layer. The ionomer not only acts as a binder, but also influences the GDE’s wetting behavior and can improve mass transport within the catalyst layer due to the combination of a hydrophobic PTFE-backbone and hydrophilic ion groups. Thus, optimizing the type and content of ionomer in the catalyst layer is of utmost importance.

In this study, we investigate how the composition of catalyst layers affects the faradaic efficiency (FE) toward ethylene during electrochemical CO2 reduction. For this purpose, we fabricate different GDEs with constant copper loading but varied ionomer content and type (Nafion, Sustainion). To assess the performance of the GDEs, we conduct electrolysis experiments in a flow cell (Flex-E-Cell) setup with KHCO3 as the catholyte. Preliminary screening experiments at up to 50 mA cm-2 reveal a strong effect of the Nafion/copper mass ratio (NCR) on the FE toward ethylene. Within the investigated range (NCRs of 0.1, 0.2, 0.3, 0.4 and 0.5), we identify a sweet spot at an NCR of approximately 0.4. We hypothesize that at higher NCRs negative effects, such as decreasing porosity and an increasingly acidic pH, outweigh the improved mass transport. To assess the performance of the different GDEs at industrially relevant conditions, we perform constant current experiments at ≥ 100 mA cm-2. Here, we corroborate the previously observed trend and find that increasing the NCR from 0.2 to 0.4 doubles the maximum observed FE toward ethylene. When replacing Nafion with an anion exchange ionomer such as Sustainion, the total FE toward carbon products remains nearly unchanged. However, the selectivity shifts from ethylene toward single-carbon species such as CO and formic acid. These results highlight that ionomers play a decisive role in hydrogen evolution mitigation and tuning of the product spectrum during electrochemical CO2 reduction.

Figure 1
Methods for Electrolyte Treatment and Hexavalent Chromium Reduction in Industrial Electrochemical Machining (ECM)
Authors: Jayasinghe Prabodha , Sneddon Scott , Gomez Gallegos Ares Argelia , Spicer Mark , De Silva Anjali K M
Published: February 2024

Electrochemical Machining (ECM) is a metal removal process that operates on the principle of anodic dissolution. ECM has the ability to produce complex shapes in difficult-to-machine alloys with precision and excellent surface finish. However, since most of these alloys contain chromium, one of the major challenges to ECM’s wider utilisation in industry is how to eliminate the resulting hexavalent chromium (Cr+6) from the spent electrolyte. This paper presents methods for controlling the Cr+6 level to within the permitted guidelines for an industry application of ECM, and reducing it to trivalent chromium (Cr+3), to then precipitating it from the electrolyte solution,

The workpiece material – Triboloy (Co; Mo; Cr alloy) has hitherto not been machined by ECM and hence no literature exists on how to treat the by-products generated. This research involves experimental analysis of various Cr+6 to Cr+3 chemical reduction methods for ECM of Tribaloy in sodium nitrate electrolyte, using spent electrolyte samples. The reduction in Cr+6 is assessed over time. It was observed that the concentration of Cr+6 decreased within a span of two minutes. Subsequently, the solution pH level was increased by the addition of an alkali to precipitate the Cr+3 ions, which then can be filtered out from the solution. The optimum solution for hexavalent chromium is thus implemented in the industrial electrolyte system for successfully machining the Tribaloy component.
Electrochemical Degradation of Toluene Using TiO2 Nanotubes
Authors: Bolaños-Romero Karla Verónica , Sandoval-González Antonia , Oza Goldie , Manriquez Juan , Bustos Erika
Published: February 2024

Toluene is a solvent widely used to produce paints, thinners, varnishes, and adhesives, as well as an octane rating improvement additive in gasoline. This compound can, unfortunately, be released into the environment in car exhaust fumes or when products containing toluene are used. Continuous exposure at high levels can cause permanent brain damage in animals. TiO2 nanotubes (TiO2,nt) increase the surface/volume ratio, as well as efficient electron transport, in the metallic substrate of Ti, enhancing the electrochemical degradation of organic compounds such as toluene.

An anodizing procedure has been performed to synthesize TiO2 in the present work. The team varied two anodizing operating conditions: potential (10, 20, 30, 40, and 50 V) and cathode material (titanium, Ti, and stainless-steel, SS) to achieve desirable results. The synthesized electrodes were characterized by Raman spectroscopy to identify the different crystallographic phases. We identified the presence of the three typical phases of TiO2 (anatase, rutile, and brookite), mainly in the synthesized electrodes at 30 V (using Ti and SS as the cathode). More significant intensity signals were observed than those corresponding to the anatase and rutile phases. Additionally, the different electrodes were analyzed by scanning electron microscopy with microanalysis (SEM-EDX) to identify the external morphology and validate their chemical composition. The toluene was hydrolyzed in ethanol with the different synthesized electrodes (Ci = 1.0 ppm, E = 2.0 V, t = 180 min, n = 150 rpm, cathode = Ti or SS). Toluene removal was monitored by gas chromatography with detector BID (CG-BID). Results indicate that the electrodes synthesized at 30 V show the highest removal efficiencies in a minimal time. The TiO2,nt|Ti synthesized using the TiO2,nt|Ti ||Ti configuration showed a toluene removal of 94.53 % in 12 min. In contrast, for the TiO2,nt|Ti synthesized using the TiO2,nt|Ti||SS configuration showed a 100 % toluene removal achieved in 6 min.

In conclusion, the best result for synthesizing the TiO2,nt|Ti reactive nanotube-rich surface was the configuration using stainless steel as the cathode (TiO2,nt|Ti||SS), applying a potential of 30 V during the 15 min anodizing treatment. This modified surface showed the highest toluene removal efficiency, 100 %, at 6 min when this VOC was dissolved in ethanol with 0.1 M KCl as the supporting electrolyte. This result is due to the anatase and rutile phases of TiO2, as verified with Raman spectroscopy. The corresponding stoichiometric relationship of two atoms of oxygen and one atom of titanium in the TiO2 nano-tubes when analyzed using SEM-EDX. After the electrolysis of toluene, the anatase phase was lost.
The Study of High-Energy Lithium Polymer Cells for Second-Life Applications
Authors: Ezeigwe Ejikeme Raphael , Erichsen Lene Therese Backus , Wahl Markus Solberg , Wind Julia , Vie Preben J. S. , Burheim Odne Stokke
Published: February 2024

The environmental impact of lithium-ion batteries (LiBs) depends directly on their useful lifetime. Doubling the useful lifetime cuts the environmental impact per functional unit in half. However, if the cell is insufficient for one application it can still be sufficient for another. The beneficial operational value of LiBs between various applications presents a prospective solution to environmental sustainability. However, the capacity and power of the LiBs tend to degrade over time, which is a major concern for its application. The investigation and identification of the several key battery aging mechanisms are essential to its second life application. This paper is focused on the experimental analysis performed on XALT 31 Ah high-energy lithium polymer cells with NMC 433 as active electrode material. Characterization and cycling tests were performed on new cells and the data obtained was compared to equal cells cycled 7 years ago. The tests were carried out with the same temperatures (25 and 45 degrees Celsius) for both new and old batteries, respectively. The internal resistance diminishes after 100 cycles for both new and old batteries at 25oC. It does however decrease more for the new batteries, than the old ones. The decrease in resistance can be due to an increase in capacity and it is normal to see in the BoL of a cell. In addition, the temperature during cycling is assumed to be higher than the storage temperature, which also can decrease internal resistance. Since both the new and old batteries behave the same way, it is argued that this is the natural development of resistance in this cell type. When cycled at 45oC, the cell resistance increased after 100 cycles. Even though resistance diminishes with increasing temperature. Other ageing mechanisms such as SEI growth and lithium plating are activated by higher temperatures, resulting in an increase in internal resistance at 45 degrees. For the new and old batteries, the dQdV curves at the BoL are very similar after 100 cycles, it is difficult to know if the trend would continue as the cells age further. Based on this study findings, new approaches can be developed for more accurate and reliable prediction on the aging degradation of high energy lithium batteries.
Effects of Secondary Phase on Electrochemical Performance of Co-Free High Entropy Spinel Oxide Anodes for Lithium-Ion Batteries
Authors: Patra Jagabandhu , Nguyen Thi Xuyen , Ting Jyh-Ming , Chang Jeng-Kuei
Published: February 2024

High entropy oxide (HEO) anode materials have recently gained significant attention in lithium-ion batteries (LIBs) due to their exceptional cycling stability, high specific capacity, and unique adjustable properties. The exclusive feature of HEO allows the use of endless element combinations to create new electrode materials with exciting and unexplored properties. In the context of Li-ion battery anode materials, unlike conventional thinking, where a single-phase high entropy oxide (HEO) is considered sufficient and necessary for delivering good electrochemical performance, we report here that this is not a necessary condition. This study demonstrates the advantages of a secondary phase in HEO. Two types of Co-free high entropy spinel oxide (HESO) are synthesized using solvothermal and hydrothermal methods, resulting in single-phase cubic HESO (HESO (C)) and binary-phase (cubic + tetragonal) HESO (HESO (C+T)), respectively. The secondary tetragonal spinel phase introduces phase boundaries and defects/oxygen vacancies in HESO (C+T), which can improve the redox kinetics and reversibility during electrode lithiation/delithiation. The minor tetragonal phase in the HESO (C+T) anode sustains after cycling, largely reducing the morphology deterioration due to improved reversibility, thus contributing to enhanced cyclability. Density functional theory calculation is performed to assess the phase stability of cubic spinel, tetragonal spinel, and rock-salt structures, and validate the cycling stability of the HEO electrodes upon lithiation/delithiation. This is the first time that the effects of a secondary phase in HEO on the electrochemical properties have been reported. A HESO (C+T)||LiNi0.8Co0.1Mn0.1O2 full cell delivers an energy density of ~610 Wh kg−1, demonstrating a great potential of the HESO (C+T) for use in LIBs. The results provide useful guidelines for designing new high-performance anode materials for LIBs.
Fast and Durable Lithium Storage Enabled By Tuning Entropy in Wadsley-Roth Phase Titanium Niobium Oxides
Authors: Zheng Jie , Xia Rui , Yaqoob Najma , Kaghazchi Payam , ten Elshof Johan E. , Huijben Mark
Published: February 2024

To date, Wadsley−Roth phase materials are one of the most promising intercalation-type hosts for fast lithium transport because of the unique crystalline diffusion channels. However, the volume expansion as well as sluggish ion/electron transport kinetics retards its application in grid scale. In recent years, various strategies have been suggested to further improve the overall performance of micro-sized Wadsley-Roth phase materials, such as oxygen vacancy creation or cation substitution.

Lately, entropy tuning has received considerable interest due to the favorable entropy-dominated phase-stabilization and ionic conductivity boosting effects.[1,2] However, it has only been applied in a few materials and the understanding of its function is still limited. It has been suggested that entropy-stabilized Wadsley−Roth shear phases with a more ordered structure would be stable upon electrochemical lithium (de-)insertion without a phase transition, while a more disordered structure would compromise the stability of the active material.[3] Therefore, suitable entropy tuning in entropy-stabilized Wadsley−Roth phase materials remains challenging and detailed knowledge about its effect on crystal structure and lithium storage is still lacking.

Here, we have successfully realized entropy-stabilized Wadsley-Roth phase Fe0.4Ti1.6Nb10O28.8 (FTNO) in which the increased entropy, due to iron substitution, leads to a reduced grain size, and therefore, a shortened Li+ diffusion channel length.[4] Secondly, the diffusion coefficient and the reaction rate constant are enhanced leading to a reduced overpotential and an improved rate performance. Benefiting from this, the micro-sized FTNO electrode exhibits an enhanced rate ability of 73.7 mAh·g-1 at 50 C as compared to 37.9 mAh·g-1 for its TNO counterpart. Thirdly, the increased entropy results in an extended cycling durability of FTNO electrode which can deliver a specific capacity of 130.0 mAh g-1 after 6000 cycles at high rate of 10 C. Operando XRD analysis demonstrates a suppression of the a-axis deformation during the first stage of the lithiation process. The mechanism is revealed by DFT calculations and found that Fe-O bond lengths undergo less changes than Ti-O during lithiation. Finally, the potential practical application of FTNO anodes has been demonstrated by successfully constructing fast charging and stable LiFePO4‖FTNO full cells.

Our results demonstrate the effectiveness of tuning entropy by iron substitution to stabilize the Wadsley-Roth phase with fast charging ability, which can be extended to other intercalation electrodes for enhanced battery applications.

[1] Y. Zeng et al., Science
2022, 378, 1320-1324.

[2] R. Zhang et al., Nature
2022, 610, 67-73.

[3] A. A. Voskanyan et al., Chem.
Mater.
2020, 32, 5301-5308

[4] J. Zheng et al., Small, smll.202301967R1, accepted.
Characterization of Nanostructured Tin Oxide Anodes Obtained By Electrolytic Oxidation for High-Energy Lithium-Ion Batteries
Authors: Lohrberg Oliver , Weiser Mathias , Heubner Christian , Michaelis Alexander
Published: February 2024

In recent years, the growing electric vehicle market has increased the need for cost efficient and high energy materials for batteries drastically. Tin and tin oxide materials bear great potential as anode materials for Li-Ion batteries due to low cost and high theoretical capacity. Nevertheless, the development of commercial tin anodes has so far been hindered due to several drawbacks related to high volume expansion during operation leading to fast cell degradation. To circumvent these issues, nanostructured electrodes can be applied to mitigate volume changes. Typically, the production process of such electrodes is challenging, leading to high cost and issues in terms of scalability. Electrochemical processes, such as the electrolytic oxidation of tin, has been found a promising alternative to fabricate nanostructured electrodes. The additive-free tin oxide anodes obtained from this process exhibit high gravimetric and volumetric capacity, excellent rate capability as well as promising cycle life. The morphology and microstructure have high impact on the rate capability and cycling stability of tin oxide anodes. Since structural properties can be precisely adjusted by controlling the electrochemical oxidation process, a deeper understanding of the structure-property relationship is needed to optimize the production process and pave the way for commercialization.

Herein an in-depth characterization of nanostructured tin oxide anodes formed by electrochemical oxidation is presented. The rate capability and the cycling stability are investigated by means of electrochemical measurements in battery cells. Operando electrochemical dilatometry is used to investigate the thickness change of the anodes during cycling (cell breathing). In-situ XRD measurements are applied to elucidate the reaction mechanism. The anodes are carefully analyzed by SEM/EDS at different state of lithiation to understand the impact of volume changes on the inner porosity and morphology. Finally, the cycling stability of tin oxide anodes is improved by applying an electrochemical prelithiation step. Therefore, the impact of different prelithiation regimes on the cycling stability is evaluated in full cells. The results contribute to the understanding of electrochemical behavior of nanostructured tin oxide anodes and the derivation of optimal design criteria adjusted by electrochemical surface engineering.
(Invited) Challenges for Accelerating Life Testing of Commercial Lithium-Ion Batteries
Authors: Gasper Paul , Sunderlin Nathaniel , Dunlap Nathan A. , Finegan Donal P. , Smith Kandler , Thakkar Foram
Published: February 2024

Life testing of commercial lithium-ion batteries is critical for predicting lifetime, anticipating failure, and guaranteeing safe operation of real-world battery energy storage systems. The traditional method for conducting life testing is to use accelerated aging experiments, where stress factors such as temperature, charge/discharge rate, or daily charge-throughput are pushed to extremes to drive cell failure, while taking care not to induce degradation mechanisms that do not reflect real-world use. But even ‘accelerated’ aging tests generally require 6 months to several years of testing to reach end-of-life for the current generation of mass-produced lithium-ion batteries. So, many efforts have been made to accelerate ‘accelerated aging’ of commercial cells throughout the battery community. But it is critical to ensure that the results of invasive or novel accelerated life testing experiments match well with not only changes to the electrochemical performance of traditionally aged cells, but also that the impacts of physical or chemical degradation mechanisms are also well characterized.

This work compares the results of a 2-year accelerated aging test conducted on 23 commercial large-format NMC-Gr cells with a variety of other accelerated life testing experiments. Coin-cell experiments using both full-cell and symmetric-cell configurations were used to study the microstructural changes and electrochemical behavior of both NMC and graphite electrodes, with the small format allowing for destructive characterization of many test replicates throughout cell lifetime; these experiments can be conducted more quickly than their large-format counterparts, and enable more detailed understanding of the degradation trajectory than the large-format test. However, difficulties in transferring electrochemical trends from the coin-cell format to the large-format cell will be discussed. In addition, cascading failure mechanisms observed in the large-format cells may not occur in coin-cells due to differences in the mechanical and thermal environment of each system. Implications for the design of small-format accelerated life testing using electrodes harvested from commercial batteries will be discussed. Calendar aging was accelerated by monitoring daily self-discharge and quantifying both reversible and irreversible capacity losses; challenges for making quantitative predictions from short-term calendar aging tests will be presented.
Can One Project Cell Lifetime Using Wide Temperature Range Ultra-High Precision Coulometry?
Authors: Tuul Kenneth , Taskovic Tina , Harlow Jessie , Johnson Michel B. , Dahn Jeff R.
Published: February 2024

Using low charge voltage with Li-ion cells significantly extends their lifetime. This makes them advantageous in enabling the implementation of Li-ion batteries for widespread renewable energy storage1. Li[Ni0.83Mn0.06Co0.11]O2/graphite (Ni83/graphite) cells combined with dimethyl-2,5-dioxahexane carboxylate (DMOHC) as electrolyte solvent and lithium bis(fluorosulfonyl)imide (LiFSI) as salt, operating to upper cutoff voltages of 3.8 or 3.9 V, can achieve incredible capacity retention and reduce gassing while cycling at 85°C2. Since these cells have exceptional lifetime projected to be decades when cycling at room temperature, there is keen interest in using high temperatures to screen cell performance in an accelerated manner3. However, how to project a high-temperature lifetime to room temperature remains to be determined.

Ultra-high precision coulometry (UHPC) can give valuable insight into cell degradation within weeks of cycling4. This has been applied to Ni83/graphite cells using a blend of DMOHC and diethyl carbonate (DEC) as electrolyte solvent, LiFSI as salt, and vinylene carbonate (VC) and ethylene sulfate (DTD) as additives. Figure 1 shows the results of UHPC measurements on a series of cells over a wide temperature range between 20-100°C to help determine pathways to project cell lifetime under normal use conditions. The results present exceptional performance at high temperatures and indicate a clear relation between degradation mechanisms and temperature. Remarkably, they also demonstrate similar capacity fade rates when the cycling temperature is increased from 55°C to 100°C. The potential causes of this are further elucidated by post-mortem electrolyte analysis of the measured cells.

REFERENCES

C. P. Aiken, T. Taskovic, and J. R. Dahn, J. Electrochem. Soc., 169, 090523 (2022).

T. Taskovic, A. Eldesoky, C. P. Aiken, and J. R. Dahn, J. Electrochem. Soc., 169, 100547 (2022).

T. Taskovic, A. Eldesoky, W. Song, M. Bauer, and J. R. Dahn, J. Electrochem. Soc., 169, 040538 (2022).

A. J. Smith, J. C. Burns, D. Xiong, and J. R. Dahn, J. Electrochem. Soc., 158, A1136–A1142 (2011).

Figure
1
. Fractional capacity fade per hour (a), fractional charge endpoint slippage per hour (b), and coulombic inefficiency (CIE) per hour (c) of Ni83/graphite cells with 1 M LiFSI in DMOHC:DEC (20:80 w/w) with 2 wt% VC and 1 wt% DTD calculated at cycle 19 of UHPC cycling at different temperatures. Notice that the y-axis is logarithmic.

Figure 1
(Digital Presentation) Crystal Structure Study of Ga-Substituted Li7La3Zr2O12 solid State Electrolyte with the Help of Rietveld Refinement
Authors: Mishra Atul Kumar , Mishra Atul
Published: February 2024

The Ga-doped Li7La3Zr2O12 (LLZO) Solid State Electrolyte (SSE) has been looked into with the help of X-ray diffraction and its structure has been successfully refined by the Rietveld method. The SSE crystallizes in the Li6.25Ga0.15La2.90Zr2O12 phase with cubic space group number 220 and unit cell parameter 13.02081 Å, and La2Zr2O7 phase with cubic space group number 227 and unit cell parameter 10.79475 Å. With 113 total reflections, the structural parameters of both the phases conversed to Rp = 13.5, Rexp = 14.16, Rwp = 18.5 and the goodness of fit i.e., χ2 was obtained as 1.74. The core of the Li-ion migration channel has been defined as the loop formed by the Li32, Li1, Li2, and Li22 sites with minimal Li...Li distance and occupational disordering of the Ga-doped LLZO SSE. The electron density plots of Li6.25Ga0.15La2.90Zr2O12 phase has shown maximum distribution of electrons inside the unit cell for lanthanum atoms. XPS confirmed the presence of all the precursors in the synthesized compound.

Figure 1
Bifunctional Deionization and Lithium Recovery Via Four-Step Constant Voltage Operation of Hybrid Capacitive Deionization with Composite Electrodes
Authors: Jeon Sung-il , Bae Sungho , Cho Kangwoo
Published: February 2024

The efficient recovery of valuable resources from wastewater has become a crucial challenge in the era of a carbon-neutral society. Capacitive deionization (CDI) has been employed in electrochemical lithium recovery (ELR) processes, based on selective Li+ intercalation to LiMn2O4 (LMO). In this study, we propose a four-step constant voltage operation (forward/zero/reverse/zero) of bifunctional hybrid CDI to produce deionized water as well as Li+-rich concentrate within a cycle. This unique performance was enabled by composite electrodes with capacitive activated carbon cloth (ACC) impregnated with redox-active LMO and Ag, respectively, which were characterized and evaluated through material characterization and electroanalysis. The proposed CDI system demonstrated deionization (step 1; forward voltage) and selective Li+ enrichment (step 3; reverse voltage) without influent replacement. The performance of the CDI system was evaluated through single pass experiments with binary NaCl and LiCl solutions (10 mM each) under 1.0/0/-1.0/0 V operation, revealing supreme performance with mass loadings of 32.6 mg/cm2 for LMO and 3.3 mg/cm2 for Ag. Furthermore, the long-term stability of the system was confirmed, indicating its potential for practical implementation. The proposed bifunctional CDI system, combining ELR with water treatment, paves the way for advancing resource recycling from wastewater.
Optimization of Synergistic Leaching of Valuable Metals from Spent Lithium-Ion Batteries by the Sulfuric Acid-Malonic Acid System Using Response Surface Methodology
Authors: Li Pengwei
Published: February 2024

A new environmentally friendly and economical recycling process for extracting metals from spent lithium-ion batteries (LIBs) using sulfuric acid and malonic acid as leaching agents is proposed. By applying Box-Behnken design (BBD) and response surface methodology (RSM) optimization techniques, the global optimal solution of the maximum leaching rate of metals in spent LIBs is realized. The results show that under the optimal conditions of 0.93 M H2SO4, 0.85 M malonic acid, liquid/solid ratio of 61 g·L–1, the temperature of 70 °C and 5 vol% of 30% H2O2, 99.79% Li, 99.46% Ni, 97.24% Co and 96.88% Mn are recovered within 81 min. The error between the theoretical value and the actual value of the metal leaching rate predicted by the regression model is less than 1.0%. Additionally, the study of leaching kinetics reveals that the leaching process of Li, Ni, Co, and Mn in spent cathode materials was affected by the synergistic effect of interfacial mass transfer and solid product layer diffusion. Economic analysis reveals that evaluation index should be fully considered when formulating recovery processes for different metals. This process can reduce the environmental risks of heavy metal disposal, and allow the reuse of metals recovered from spent LIBs.
Effect of Water Vapor on Hydrogen Isotopes Separation by Polymer Electrolyte Fuel Cell
Authors: Furusawa Koichiro , Nago Toranosuke , Ueda Mikito , Matsushima Hisayoshi
Published: February 2024

Introduction

Hydrogen isotopes are protium (H), deuterium (D) and tritium (T). D and T are important materials not only for fission and fusion reactors, but also for semiconductors since the strong hydrogen termination improves the durability. Various techniques for hydrogen isotope separation have been known for long time, but they have some drawbacks such as low separation efficiency and poor energy consumption. Therefore, new separation and purification methods are required.

In polymer electrolyte fuel cell (PEFC), wettability is optimized well and small amount of Pt catalyst is used. The configuration is also key issue for the conventional method of water-hydrogen chemical exchange. Therefore, we investigated the effect of water in hydrogen isotope separation by PEFC [1].

Experimental

A mixture hydrogen gas of H2 and D2 was supplied to the PFEC. The separation factor for dry and wet gas flow was measured, respectively. Hydrogen gas and water vapor from PEFC were analyzed by quadrupole mass spectrometry (Q-mass) and Fourier infrared spectrometer (FTIR), respectively. The separation factor and mass balance were calculated.

Results and discussion

When no electricity was generated, FTIR results showed that D was enriched in water vapor. This is explained by a gas-phase chemical exchange reaction occurring on a platinum catalyst. When the PEFC was operated, the electrochemical reaction promoted the D separation. A large amount of D (about 45%) was transferred to water vapor during power generation. The separation factor was approximately 1.7, while it was approximately 1.3 for no generation. The present results suggested that gas-phase chemical exchange and the cell reaction had a synergistic effect on D separation.

References

[1] K. Furusawa et al., Int. J. Hydrog. Energy, 47, 36248-36253 (2022).
Deuterium Isotope Separation By Polymer Electrolyte Fuel Cell with Gas Circulation System
Authors: Nago Toranosuke , Furusawa Koichiro , Ueda Mikito , Matsushima Hisayoshi
Published: February 2024

Introduction

Hydrogen isotopes such as deuterium (D) and tritium (T) are in increasing demand in the fields of materials, energy, and medicine. A international fusion reactor in France will be equipped with water electrolysis for T separation. New methods are required, since the conventional processes perform low separation and consume large amount of energy. We have been studying D separation by polymer electrolyte fuel cell (PEFC) [1-3]. Here, the relationship between the gas consumption rate and separation efficiency is investigated. Therefore, the present PEFC can recirculate the unreacted hydrogen gas discharged from the anode, which proceeds high gas utilization. In our poster presentation, we will show the separation factor, D concentration and production volume depending on the gas circulation ratio.

Experimental

A JARI cell (electrode area: 25 cm2) was used for PEFC, and platinum was used as catalyst for both electrodes. For the anode, protium (H) concentration was set to 90 at% as a mixed gas. Oxygen gas was supplied to the cathode. Power generation was performed at room temperature, and a constant output current was obtained using a variable resistor. The H concentration in the anode gas was analyzed with a quadrupole mass spectrometer, and the gas volume discharged from the PEFC circulation system was calculated.

Results and discussion

The ratio of the hydrogen gas circulation rate to the supply rate is defined as λ. The relationship with the H concentration is shown (Fig. 1). The H concentration was enriched during PEFC operation, while D was condensed in produced water. The gas circulation improved the separation efficiency because the outlet gas was repeatedly processed in PEFC. Figure 2 shows the relationship between λ and the volume rate of exhaust gas from anode. As λ increased, the gas rate decreased linearly from 8 mL min-1 to 2 mL min-1. That is, the circulation system let the gas residential time in PEFC be longer. When the gas was circulated more, the gas could react for long time. This was attributed to the high H concentration seen in Fig. 1. The present results demonstrated the importance of circulation parameter, λ, for the enrichment production.

References

[1] K. Furusawa et al., Int. J. Hydrog. Energy, 47, 36248 (2022).

[2] R. Tanii et al., Int. J. Hydrog. Energy, 44, 1851 (2019).

[3] R. Ogawa et al., Energy, 149, 98 (2018).

Figure 1
(Invited) Electro-Separation Combined with Electro-Conversion for Wastewater Treatment and Recovery: Case Study of Electro-Precipitation or Electro-Sorption Combined with Advanced Electro-Oxidation
Authors: Mousset Emmanuel
Published: February 2024

The water stress combined with an increase of water demand lead to a worldwide water crisis that is urgent to solve. The United Nation has established sustainable development goals to deal with this challenge. In the meantime, raw materials resources are decreasing, drastically for some of them. Thus, 30 critical raw materials (e.g., rare earth elements, phosphorus, magnesium) have been listed by the European Union in 2020. The reuse of treated wastewater remains one of the most effective solution, while the concomitant recovery of value-added compounds is gaining increasing interest.

To answer this issue, advanced physico-chemical treatments need to be developed in order to separate the value-added compounds from the solution, while the non-valuable biorecalcitrant pollutants must be eliminated. Electrochemical systems are arising importance. Their heterogeneous nature can involve electro-catalysis through the development of innovative multi-functional materials, which is a further step towards the rise of greener processes by avoiding chemicals addition. Electro-separation technologies are able to selectively isolate compounds according particularly to their electrophoretic mobility, the applied current & electrode potential, the electrode materials properties and the electrolyte characteristics. They can be competitive by increasing the selectivity of separation. In the meantime, electro-conversion systems are able to mineralize recalcitrant organic pollutants from wastewater, while value-added organic compounds can be obtained by electro-synthesis. Therefore, the coupling between electro-separation and electro-conversion systems seems promising to solve water issues.

In this talk, two case studies will be presented, one about the electro-precipitation in combination with advanced electro-oxidation and the second case about electro-sorption coupled with advanced electro-oxidation. In the first study, the possibility to recover phosphate, while eliminating tylosin as representative pharmaceutical pollutant will be presented. In the second work, the recovery of phenolic compounds from olive mill wastewater will be exposed, considering the subsequent elimination of residual organic pollutants from the effluent. Emphasis will be given on engineering (e.g., reactor design) and modeling aspects.