bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Sustainable Lithium-Ion Battery Anodes: Addressing the Critical Need for Graphite Recycling
Authors: Oftedal (Naldoni) Liv (Clicia) , Skomedal Gunstein , Hansson Robin
Published: February 2024

Graphite is the predominant anode material for all lithium-ion batteries (LIB) currently manufactured. However, despite comprising between 10 and 20 percent of a LIB's weight, graphite is not typically recycled. Graphite has a wide variety of applications outside of LIB, but the value of use in other applications is very low, so only recycling graphite back into anode material will be economically viable. Since graphite is such a stable substance, it should in theory be highly desirable for direct recycling back into anode material. As a result of this stability, several sources of graphite can become intermixed and impossible to separate later, posing a traceability issue. As is the case with cathode materials, there is currently no policy mandating the recycling of graphite.

At the same time, graphite (natural) is on the EU's list of critical raw materials (98% imports), and the global supply of graphite for anode materials is entirely dominated by China. The production of natural and synthetic graphite has significant environmental costs, with recent studies indicating a CO2 footprint in the range of 10 to 30 kgCO2/kg graphite, which is significantly higher than what was previously reported in LCA literature. There is a need to establish processes for recycling this valuable material, as its demand is expected to increase dramatically over the next decade.

In recent years, Vianode has developed a one-of-a-kind method for converting graphite concentrates from LIB production scrap and end-of-life batteries (black mass) back into anode-grade graphite for use in new LIB. Using a high temperature purification stage, impurities and flaws in graphite can be effectively removed and a purity of over 99.99% can be attained. Cell testing reveals that recycled graphite can achieve the same properties as virgin graphite, including outstanding reversible capacity, first cycle efficiency, fast charge capability, and cycle life. The results indicate that graphite recycling should be implemented as soon as possible to lessen the EU's reliance on graphite imports and significantly reduce the environmental impact of anode materials in LIB.
Experimental Analysis of the Current Distribution between Graphite and SiOx in Blend Electrodes for Lithium-Ion Cells
Authors: Knorr Julian , Kufner Thomas , Adam Alexander , Danzer Michael Anton
Published: February 2024

The demand for battery cells with increased energy density without sacrificing performance is driving research into investigating new active electrode materials. The addition of silicon oxide as a second active anode material alongside graphite, referred to as graphite/SiOx blend electrodes, offers a great opportunity to increase the specific capacity of lithium-ion cells. The stable structure of graphite in combination with the high theoretical capacity of silicon represents a promising improvement, for example to increase the driving range of electric vehicles.

In this work, the electrochemical behavior during the lithiation and delithiation process of blend electrodes is analyzed. Two custom-made cells are connected in parallel, with each of the cells containing either pure graphite or pure SiOx as the working electrode. Both cells use similar counter electrodes. The experimental setup enables the measurement of the current distribution during charging or discharging of the parallel connection. The observed individual current flow to each cell represents the current flow to each active material. This allows conclusions to be drawn about of the electrochemical processes in a graphite/SiOx blend electrode [1].

This work focuses on two effects of blend electrodes: First, the lithiation differences between the active materials with increasing charge rates. Changes in the lithiation distribution between the active materials are observed at higher currents. Second, the effect of hysteresis on the lithiation of blend electrodes. When stating the lithiation process with a fully or partially delithiated blend electrode, the increased delithiation potential of SiOx [2] causes differences in the lithiation distribution between the materials. The knowledge gained on graphite/SiOx blend electrodes contributes to a better understanding of lithium-ion cells and to the optimization of their integration in electric vehicles.

References

[1] Heubner, Christian, et al. "Understanding Component‐Specific Contributions and Internal Dynamics in Silicon/Graphite Blended Electrodes for High‐Energy Lithium‐Ion Batteries." Batteries & Supercaps 5.1 (2022): e202100182.

[2] Jiang, Yang, et al. "Voltage hysteresis model for silicon electrodes for lithium ion batteries, including multi-step phase transformations, crystallization and amorphization." Journal of The Electrochemical Society 167.13 (2020): 130533.
Highly Porous Fe3O4/Graphene Aerogels for Enhanced Lithium Storage
Authors: Wang Fei , Wen Xinyue , Joshi Rakesh , Kundu Dipan
Published: February 2024

A facile and green method was adopted to produce iron oxide/graphene composite which can be used as free-standing and additive-free electrodes in lithium-ion batteries. In the synthesis process, after graphene oxide and FeCl3 being mixed in aqueous media and subsequently being freeze-dried into the form of aerogel, FeCl3 reacts with epoxy groups on graphene oxide under N2 to from Fe3O4 nanoparticles and simultaneously reduce graphene oxide in the heat treatment, leaving behind a hierarchically porous graphene matrix on which Fe3O4 nanoparticles were uniformly dispersed. Such composite products, featured by its high porosity and homogeneous distribution of Fe3O4 nanoparticles, showed an enhancement in the electrochemical performance when used as anode materials in lithium-ion batteries. This work investigated the role of preparation parameters including the weight ratio of Fe3O4/graphene and heating temperature in affecting the electrochemical performance of as-prepared electrode. F1G2-600 presented a high reversible capacity of 1224 mAh/g at 0.1 A/g with the Coulombic efficiency of 73.8% in the first cycle. In the long-term test, F1G2-600 still delivered a remaining capacity of 573.8 mAh after 1000 cycles at 1 A/g with a retention rate of 82.8%. Therefore, this easily fabricated Fe3O4/graphene composite with high capacity and desirable durability holds promise in the scalable application as anode materials in high-power LIBs.
Lithium-Ion Battery Electrolyte Miscibility Studied By Spectroscopy
Authors: Reiner Sofia , Pechberty Clément , Maibach Julia , Johansson Patrik
Published: February 2024

Interfaces, interphases, and surfaces are of immense interest to the battery research community since the key reactions and much of the kinetics that determine the performance of the cell occur there. While solid/liquid and solid/solid interfaces have been thoroughly studied, liquid/liquid interfaces have attracted much less attention.

Here we target the liquid/liquid interfaces between two liquid electrolytes, employed to create dual electrolyte batteries. The grand idea is that based on two either chemically or mechanically immiscible electrolytes we can expand the overall electrochemical stability window to achieve both high electrolyte oxidation stability on the positive electrode and efficient and stable solid electrolyte interphase (SEI) formation on the negative electrode [1][2].

To understand the dual electrolyte systems created we study diffusion across the liquid/liquid interfaces, the formation of any emulsion layers, and if there are chemical reactions occurring. We use confocal Raman spectroscopy focusing on the interface between two porous separators soaked with two different electrolytes as well as in situ Raman depth profiling with micrometer resolution, including the role of pressure to the stack of separators (both glass fibre and polymer based).

The observations of for example diffusion and mixing are subsequently correlated with the physicochemical properties of the two electrolytes in order to pave the way for rational design of a dual electrolyte cell.

[1] S. He, S. Huang, Y. Zhao, H. Qin, Y. Shan and X. Hou. “Design of a Dual-Electrolyte Battery System Based on a High-Energy NCM811-Si/C Full Battery Electrode-Compatible Electrolyte”. ACS Applied Materials & Interfaces 2021 13 (45), 54069-54078. DOI: 10.1021/acsami.1c17841

[2] Ren, Y., Manthiram, A., “A Dual-Phase Electrolyte for High-Energy Lithium–Sulfur Batteries. Adv. Energy Mater”. 2022, 12, 2202566. https://doi.org/10.1002/aenm.202202566
Silicon Oxycarbide-Coated Bismuth for Enhanced Anode Stability in Lithium-Ion Batteries
Authors: Mohd Sarofil Anith Dzhanxinah , Devina Winda , Park Hyeon Seo , Kim Jaehoon
Published: February 2024

The current state-of-the-art lithium-ion batteries (LIBs) with graphite as an anode foresees shortcomings to demands in energy storage and supplies with high energy and power densities for large-scale applications such as electric vehicles. Metallic Bi alloy is among the promising alternative alloy candidates to replace the graphitic anode owing to its high volumetric capacity (3765 mAh cm−3), relatively small volume expansion (~215%), and unique layered crystalline structure with large interlayer spacing along the c-axis (d
003 = 3.95 Å). Nevertheless, inevitable volume expansion during repetitive Li+-ion insertion/extraction build-ups localized mechanical strain, causing particle pulverization, cracking, and isolations, eventually leading to cell failure. Herein, to achieve decent reversibility of alloys, we introduce a polymer-derived ceramic silicon oxycarbide (SiOC) coating onto Bi nanoparticles (NPs) via facile dispersion of bismuth hydroxide in silicone oil and consecutive heat treatment. The SiOC coating layer alone is an active conversion material with a higher specific capacity but lower volumetric capacity than Bi. To promote the fabrication of high volumetric capacity Bi-based composites using higher tap density materials with a well-balanced specific capacity, the content of the metal precursor and silicone oil were varied. The sturdy SiOC matrix embedded with the Bi NPs cushions the stress cultivated upon (de)lithiation reactions, achieving stable capacity (507 mAh g−1 at 0.05 A g−1 after 150 cycles), high volumetric capacity (872 mAh cm−3), superb cyclic stability (380 mAh g−1 at 0.5 A g−1 after 500 cycles), and adequate cell integrity when tested as an anode in a half cell. In a full cell configuration coupled with a LiNi0.5Co0.2Mn0.3O2 cathode, high gravimetric and volumetric energy densities of 343 Wh kg−1 and 607 Wh L−1 can be estimated, respectively. The conducted kinetic and postmortem analyses provide additional insights into the effectiveness of amorphous SiOC as a protective layer in preventing excess solid electrolyte interface passivation and preserving the electrically conductive network for continuous transport of ions and electrons.

Figure 1
SnBi Alloy Composites Via Controlling Cooling Rate for High Performance Lithium-Ion Battery Anode
Authors: Park Hyeon Seo , Devina Winda , Mohd Sarofil Anith Dzhanxinah , Kim Jaehoon
Published: February 2024

Alloying-based materials, such as tin (Sn) and bismuth (Bi), have been considered as potential anode materials for lithium-ion batteries (LIBs) due to their high theoretical volumetric capacities of 1991 and 3765 mAh cm−3, respectively. However, these materials tend to have short cycle lives due to severe volume expansion when fully lithiated, such as Li4.4Sn (300%) and Li3Bi (215%), which presents a great challenge for practical implementation. To address this issue, using two metal alloys is an effective strategy to improve electrode integrity and stability. The different working voltages of Bi (0.78−0.69V) and Sn (0.65−0.1V) hinder the extreme structural changes that occur upon cycling. At the initial discharge stage, the unreacted Sn phase acts as a buffer during the lithiation of Bi. Meanwhile, the lithiated state of Bi (LixBi) will buffer the expansion when Sn is lithiated with Li-ions. However, the definition and mechanism of the buffer effect between active-active metals are still unclear. As a result, the bismuth-tin (BiSn) alloy is designed through heat treatment by controlling the cooling rate to form micro-phase alloys (BiSnM) and nano-phase alloys (BiSnN). The BiSn nano-phase alloy anode (BiSnN) exhibits a better buffer effect and achieves a superior discharge capacity of 550 mAh g−1 at 0.1 A g−1 and 320 mAh g−1 at 2 A g−1.
Battery Modeling: Fusing Equivalent Circuit Models with Data-Driven Surrogate Modeling
Authors: Jin Limei , Bereck Franz Philipp , Granwehr Josef , Eichel Rudiger-A , Reuter Karsten , Scheurer Christoph
Published: February 2024

Electrochemical impedance spectroscopy (EIS) is widely used to characterize electrochemical energy conversion systems. The traditional analysis with equivalent circuit models (ECM) has recently been augmented by a transform based distribution of relaxation times (DRT) analysis which allows one to reduce the ambiguity in the construction of ECMs and thus overfitting. Experimentally determined ECM parameters vary depending on operating conditions and the lifetime history of battery usage. Here we focus on State of Health (SOH) and State of Charge (SOC) as a basis for operando diagnosis and functionality optimization in the setting of fast-charging. Within pure ECM approaches, aging effects can only be represented to a limited extent, as aging is related to a variety of different factors whose impact on cell impedance are not sufficiently understood, yet. The highly complex interplay of factors motivates the development of data-driven Machine Learning (ML) models as a basis for future battery management systems. We present ML enabled ECMs based on experimental impedance analyses and a data-driven ML approach that computationally samples an abstract target space for classification and recognition of cells at vastly different SOC/SOH combinations.
Modulation of Prelithiation Solution for Hard Carbon Anodes of Lithium-Ion Batteries
Authors: Patra Jagabandhu , Chang Jeng-Kuei
Published: February 2024

The increasing demand for high-energy and high-power lithium-ion batteries (LIBs) in portable gadgets and electric vehicles has led to exploration of high-performance silicon and hard carbon (HC) anodes to replace traditional graphite anodes. However, their practical application is hindered by low initial coulombic efficiency and large irreversible capacity, which decreases the total energy density. Prelithiation is a strategy to restore energy density by supplying additional Li ions. Chemical prelithiation, involving immersing the electrode in a reductive Li−aromatic hydrocarbon (arene) complex solution, is a standout method due to its safety, high efficiency, and practical feasibility. It not only restores the lost lithium but also aids in maintaining a more stable solid electrolyte interphase layer to guarantee battery cycling stability. The first part of our study addresses the issue of expensive and impractical arene complexes for prelithiation, we focus on using low-cost and commercially available aromatic compounds such as naphthalene and methyl-substituted naphthalene compounds. This study investigates the effects of electron-donating methyl groups on naphthalene on the prelithiation activity toward HC using density functional theory calculations. In the second part of this study, we use low-cost and easily available solvents such as ethylene glycol dimethyl ether, bis(2-methoxyethyl) ether, and triethylene glycol dimethyl ether for chemical prelithiation. Ether solvents have a desirable solvation effect with Li+, and the ether with low solvation power enhances the prelithiation activity. The degree of prelithiation is greatly affected by the reaction time, and the details of this relationship are rarely investigated. In the final part of our study, we conduct a detailed investigation on the effects of various reaction times on the prelithiation activity toward the HC anode. This study provides useful insights for effective prelithiation, in terms of choosing aromatic compounds, solvents, and reaction time.
Why Li(1-x)FePO4/ LiFePO4 Is a Good Candidate to be Used as Reference Electrode
Authors: Genies Sylvie , Balfet Pierre , Villemin Elise , Septet Cédric , Ranieri Marco , Franchi Romain , Raccurt Olivier
Published: February 2024

Fundamental electrochemical studies require the implementation of a reference electrode inside the cell to record the potential profile and characterize the kinetic properties as well as the interface structure of each electrode [1]. Obtaining such data is essential for a better understanding of the electrochemical processes and the aging mechanisms generated by cycling. This is challenging for lithium-ion technologies for which no reference electrode is commercially available. LixFePO4 (LFP), a biphasic material, has been identified as a possible reference material, because its insertion/de-insertion curves show a voltage plateau over a wide lithiation range (Figure 1). Literature reports studies of instrumented pouch cells with a reference electrode in LFP [2, 3]. One important criterion to consider is the stability of the potential of LFP over time and the impact of temperature on the potential in the perspective to develop innovative smart-cell. The response will be provided according to the stability study of the Li0.5FePO4 potential. The methodology, used to evaluate the operating time of the reference electrode in LFP is based on monitoring the open circuit potential (OCV) of Li0.5FePO4 versus lithium over time and at different temperatures. The used cell configuration used is illustrated in Figure 2. We will also present the entropic behaviour of LFP which will confirm why LFP is a good candidate for reference electrode.

REFERENCES:

[1] Electroanalytical Methods Guide to Experiments and Applications, Springer; Edition: 2nd ed. 2010 (11 November 2014)

[2] I. Jiménez Gordon, S. Grugeon, A. Débart, G. Pascaly, S. Laruelle, Solid State Ionics 237 (2013) 50–55

[3] F. La Mantia, C.D. Wessells, H.D. Deshazer, Yi Cui, Electrochemistry Communications, Vol. 31,2013, 141-144

ACKNOWLEDGMENTS:

INSTABAT project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 955930.

Figure 1
Analysis of Structural Changes in Practical Batteries during Overcharging Using Synchrotron X-Ray CT Imaging
Authors: SHI Xian , Watanabe Toshiki , Yamamoto Kentaro , Kato Shiro , Fujii Masanori , Kinoshita Hajime , Matsunaga Toshiyuki , Uchimoto Yoshiharu
Published: February 2024

Lithium-ion rechargeable batteries are desired for applications such as power sources for electric vehicles, which require increased energy density to extend cruising range. In the cathode, increasing the nickel content makes it possible to increase the energy density, but this is problematic due to a decrease in safety. To solve this problem, it is necessary to clarify the phenomena leading to structural breakdown by operando observation[1]. We have developed a system for operando non-destructive observation of the internal structure of all batteries under transient conditions using 100 keV collimated light of SPring-8 beamline. In this study, the difference in the behavior of LiCoO2 (LCO), LiNi0.6Mn0.2Co0.2O2 (NMC622) and LiNi0.8Mn0.1Co0.1O2 (NMC811) during overcharging was discussed in combination with the measurement of the electronic structure of the cathode active materials from the surface to the bulk.

A 40-layer laminated battery (1 Ah) was used, with LCO, NMC622 and NMC811 as the cathodes and natural graphite as the anode. After charging to 100% SOC at 1C (1C=160 mAh/g) rate at room temperature, the overcharge process performed under 3C and/or 6C rate from 100% SOC while measuring voltage and temperature. Overcharge behavior inside the battery was observed simultaneously by operando X-ray CT during overcharge process.

During the overcharge test at 6C rate, the maximum temperature of the LCO laminated battery was 390 ℃, while NMC811 laminated battery reached over 600 ℃ (Fig. 1). Point 1 in Fig. 1 is the point where changes in the electrode structure begin to be observed by the operando X-ray CT measurements. The point 1 of NMC811 occurred earlier (203 s) than LCO (542 s). From the O-K XAS result (Fig. 1d), the pre-edge (located at 519 ev) of NMC811 was much higher than LCO and NMC622 when overcharging to 200% SOC, meanwhile the O-Ni bond in NMC is more unstable than O in LCO in the overcharged state. The unstable electronic structure of oxygen on the surface of NMC811 is the starting point for the rapid structural change of the battery during overcharging.

Reference
s
:

[1] Donal P. Finegan; Mario Scheel; James. Robinson; Bernhard T.; Marco Di M.; Gareth H. Phys.Chem.Chem.Phys. (2016), 18, 30912.

Figure 1
Flux Growth and Surface Modification of Highly-Crystalline Active Materials and Solid Electrolytes for High Performance Libs
Authors: Shishino Kazuyuki , Yamada Tetsuya , Hayashi Fumitaka , Terashima Chiaki , Teshima Katsuya
Published: February 2024

Materials for energy devices are often multicomponent with a number of interfaces and heterojunctions. In particular, lithium-ion batteries (LIBs) have been studied extensively because of their potential use as power sources. Recently, there has been a particular focus on all-solid-state LIBs (and high-performance LIBs). They have attracted considerable attention due to their high energy densities, which are the result of device miniaturization, and high safety due to their non-flammability. However, there is an extremely large innovation gap between general purpose LIBs and all-solid-state LIBs due to difficulties in the smooth transfer of lithium ions, i.e., the diffusion of lithium ions and electrons are disturbed at the interfaces of different solid materials. Therefore, we have tried to control and design their interfaces between active materials and solid electrolytes and fabricate materials for all-solid-state LIBs based on crystal science and engineering. Our research group has developed flux crystal growth and its extended methods for the preparation of high crystalline materials. Flux method is a liquid phase crystal growth in which idiomorphic highly crystalline particles can be obtained below the melting point of the target. Therefore, outmost crystal planes are tuned by our techniques where they have desired various ion and electron paths (i.e., hyper-spaces). In addition, the grown crystals are expected to have high crystallinity because diffusion and rearrangement of atoms easily occurred compared to conventional particle fabrication methods. Recently, we have developed a flux method to fabricate crystal layers on various substrates, which is called "flux coating method". For example, the target LIB-based materials are cathode active materials such as LCO, LNM, NCM, LFP and so on, anode active materials such as LTO, TNO and the related materials, and solid electrolytes such as LLZ, LLT, LLN, etc. and their crystal layers. Furthermore, their surface conditions are precisely controlled in our laboratory. Details on material design and hyperspace control of flux-grown crystalline particles and crystal layers via flux-related techniques will be reported at the 244th ECS Meeting.
Extreme Fast Charging of High Energy Density Lithium Ion Battery
Authors: Lee Jin wook , Park Sung-min , Sun Yang-Kook
Published: February 2024

The demand for high-energy-density batteries using Ni-rich cathodes is increasing due to the continuous expansion of the electric vehicle (EV) market. U.S. Department of Energy has stated the need for extreme-fast-charging (XFC) batteries that achieve an 80% state of charge (SOC) in less than 15 min. However, Ni-rich cathodes tend to lose capacity quickly under XFC conditions, which compromises their structural integrity. In addition, XFC conditions rapidly generate significant heat due to the high current applied to the cell, leading to the degradation of cell components. It is challenging to create Ni-rich cathodes that can withstand XFC conditions while still maintaining maximum energy density and long-term cycling performance. In this study, a cathode called Li[Ni0.92Co0.06Al0.01Nb0.01]O2 (Nb-NCA93) is introduced, which has a high energy density of 869 Wh kg-1. The presence of Nb in the cathode induces grain refinement in its secondary particles, reducing internal stress and preventing heterogeneity of Li concentration during cycling. When used in a full-cell, the Nb-NCA93 cathode reaches full charge within 12 minutes and retains 85.3% of its initial capacity after 1000 cycles, cycled at full depth of discharge. Furthermore, the refined microstructure of the Nb-NCA93 cathode limits heat generation under XFC conditions.

References

H.-H. Ryu, K.-J. Park, C. S. Yoon, Y.-K. Sun, Chem. Mater. 2018, 30, 1155

C. S. Yoon, H.-H. Ryu, G.-T. Park, J.-H Kim, K.-H. Kim, Y.-K Sun, J. Mater. Chem. A 2018, 6, 4126

U.-H. Kim, H.-H. Ryu, J.-H. Kim, R. Mücke, P. Kaghazchi, C. S. Yoon, Y.-K. Sun, Adv. Energy Mater. 2019, 9, 1803902
Fabrication and Characterization of LiNi1/3Mn1/3Co1/3O2/Li0.6La0.4TiO3/Li4Ti5O12 Full Cell All-Solid-State Thin Film Li-Ion Batteries for Energy Applications
Authors: Subash Sruthy , Yasui Shintaro , Kiguchi Takanori , Karuppanan Kamala Bharathi
Published: February 2024

Recent days, natural calamities caused by the global warming and climate changes are major concern for the entire globe and there is a pressing need to address such issues to save the mankind from further havoc and devastation. To reduce the carbon emission, countries are shifting dramatically towards renewable sources for their energy needs for their day-to-day life. Li ion batteries are in the forefront of the battle towards the sustainable growth and development due to their high energy density and renewable in nature. In the present case, we report on development of thin film based all-solid-state batteries (ASSB) for energy applications. LiNi1/3Mn1/3Co1/3O2 (NMC), Li0.6La0.4TiO3 (LLTO) and Li4Ti5O12 (LTO) materials are employed as a cathode, solid electrolyte and anode layers for fabricating a full cell all-solid-state thin film batteries. All the layers are fabricated employing RF sputtering technique. Before fabricating the full cell, individual layers are fabricated and their electrochemical and/or ionic conductivity properties are explored. Li0.6La0.4TiO3 solid electrolyte thin films are seen to exhibit room temperature in-plane ionic conductivity in the order of 10-3 S/cm. NMC thin film with the thickness of 100 nm exhibits specific capacity of 91 µAh/cm2 and the redox peaks at 3.8 V and 3.5 V. LTO anode thin films shows the specific capacity close to 100 mAh/cm2and the redox peaks around 1.5 V. XRD pattern of NMC/LLTO/LTO full cell shows the diffraction peaks corresponding to all the three layers. Cross-sectional scanning electron microscope (SEM) image indicates the uniform coating and presence of all the layers. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) along with the energy dispersive X-ray is employed to image the cross-sectional details and the elements present in each layer of the full cell all-solid-state thin film battery. Impedance spectroscopy was employed to calculate the total conductivity of the fabricated full cell. Obtained results indicates that the full cell NMC/LLTO/LTO thin film batteries can be fabricated employing a sputtering technique for the energy applications.

Figure 1
Stabilizing the Reversible Oxygen Redox Reactions in Lithium-Rich Layered Cathodes Via the Surface-to-Bulk Enhanced D-P Hybridization
Authors: Yin Zijia , Yin Zijia
Published: February 2024

The oxygen redox (OR) reaction in layered Li-rich oxide (LLO) cathode materials has been an attractive topic as it provides additional capacity. However, the suppression of the irreversible transition metal (TM) migration and oxygen release induced by the OR reaction is still a challenging issue, as it would lead to a severe capacity and voltage decay. Here, we introduce a surface-to-bulk structure modification strategy, namely surface Ni segregation and bulk Mo doping structure. Based on this strategy, the oxygen atoms near the surface are fully coordinated, and meanwhile the distortion of the metal–oxygen octahedron is alleviated in the bulk phase, thereby enhancing the degree of TM 3d and O 2p hybridization to stabilize the metal–oxygen framework for the OR reaction. It suppresses cation migration and oxygen release and maintains phase stability, allowing a reversible OR reaction. As a result, the capacity and voltage retention of the modified materials were significantly improved. This work gives an efficient method to stabilize the OR reaction through the surface-to-bulk enhanced d-p hybridization and provides new paths for the design of Li-rich cathodes.
Transition Metal-Doped Co-Free Layered Cathode for High-Performance Li-Ion Batteries
Authors: Park Geontae , Kim Myoung-Chan , Sun Yang-Kook
Published: February 2024

Surging demand for high-energy-density cathodes based on Li(Ni
x
Co
y
Mn1−x−y
)O2 (NCM) and Li(Ni
x
Co
y
Al1−x−y
)O2 (NCA) for LIBs for EVs has tripled the price of Co in three years. As the price of Co rises rapidly, efforts to remove Co from the cathodes are increasing, but Co, even in minute amounts, plays an essential role in maintaining rate capability and structural stability while reducing cation mixing.1 So the realization of high-performance, Co-free layered cathodes poses a serious technical challenge. Recently, LiNi0.9Mn0.1O2 (NM90) was proposed as an alternative Ni-rich, Co-free cathode material.2 Although the long-term cycling stability of the NM90 is acceptable, its capacity is substantially less than that of a LiNi0.9Co0.05Mn0.05O2 (NCM90) when the NM90 is charged to a standard operating voltage (4.3 V) because the charging ends in the midst of the second hexagonal phase (H2) to the third hexagonal phase (H3) transition. In this study, we investigate to stabilizing the delithiated structure of an NM90 cathode at 4.4 V is proposed, namely, the introduction of a tertiary element into the cathode in combination with the modification of the electrolyte. The introduction of 1mol% Mo into NM90 accompanies increasing in the upper cut-off voltage to 4.4 V (versus Li+/Li) can help realize a half cell, delivering a capacity of 234 mAh g-1 that is comparable to that of NCM with similar Ni contents. The cycling stability of a full cell featuring the Li(Ni0.89Mn0.1Mo0.01)O2 (Mo–NM90) cathode is enhanced with a modified electrolyte (EF91, EMC:FEC = 9:1); retaining 86% of its initial capacity after 1,000 cycles while providing 880 Wh kgcathode
−1. Mo–NM90 cathode is able to deliver a high capacity with cycling stability suitable for the long service life for electric vehicles at a reduced material cost, furthering the realization of a commercially viable Co-free cathode for LIBs.

Reference
s
:

[1] C. Delmas, I. Saadoune, A. Rougier, J. Power Sources, 44 (1993) 595-602.

[2] A. Aishova, G.-T. Park, C. S. Yoon, Y.-K. Sun, Adv. Energy Mater. 10 (2019) 1903179.
Understanding the Connection between Li-Ion Transport Number and Electrochemical Performance in Fluorinated Ether-Based Electrolytes
Authors: Ishfaq Hafiz Ahmad , Talian Sara Drvarič , Dominko Robert , Gaberscek Miran , Johansson Patrik
Published: February 2024

As high-performance batteries increase in demand, lithium metal batteries (LMBs) have attracted increasing attention in recent years. Nonetheless, LMBs are limited in their performance due to a low cation transport number (tLi+) of non-aqueous liquid electrolytes, which is the ratio of charge transport of Li-ions to its counterion. This study investigated fluorinated ether-based electrolytes (1,2-(1,1,2,2-tetra fluoroethoxy) ethane, TFEE) with 1,2-dioxolane (DOL) as a co-solvent that were found to have tLi+ of 0.70, which was determined through electrochemical impedance spectroscopy, EIS. This electrolyte mixture gives a low electrolyte coulombic efficiency and poor stability tested in both Li-Cu half and Li – Li4Ti5O12 full cells. The same fluorinated electrolyte with dimethoxy ethane (DME) as a co-solvent showed better coulombic efficiency and stability despite its low tLi+ of 0.18. A significant migration resistance through the porous solid electrolyte interface (SEI) in the case of TFEE-DOL electrolytes is suspected to explain the observed discrepancy, as demonstrated by EIS and X-ray photoelectron spectroscopy. We propose that the properties/process of the Li anode are more crucial for LMBs’ performance than the ionic transport through the bulk electrolyte. Furthermore, the transport number should be determined carefully to avoid any spurious effects associated with SEI properties.

Acknowledgments

This work has received funding from the European Union Horizon 2020 research and innovation DESTINY program under grant agreement No. 945357. Co-financing from Slovenian Research Agency (ARRS) is fully acknowledged.
Synthesis of Polyhydroxy Urethane Network Based Solid Polymer Electrolytes from Bio-Sourced Carbonates and Amines
Authors: Raj Ashish , Grignard Bruno , Detrembleur Christophe , Gohy Jean-François
Published: February 2024

Climate change is a harsh but ultimate reality, impacting every corner of the globe. This stresses the strong emphasis on the need for clean renewable energy with safe storage technology, particularly batteries. Solid-state batteries are of great interest owing to their higher energy density, flexibility and safety than the existing lithium-ion batteries technology. While there is constantly increasing research on polyethylene oxide (PEO) based polymers, we aim at PEO alternatives that are sustainable and environmentally friendly. In our project, we demonstrate a bio-derived solid polymer electrolyte based on functionalized carbonated soybean oil (CSBO) monomer for the synthesis of polyhydroxy urethanes (PHUs) network. This class of materials shows remarkable adhesive properties on the surface of lithium speculating better interfacial contact and stability. All these polymers reinforced with LITFSI were characterized following standard electrochemical measurements exhibiting decent ionic conductivity (>10-2 mS cm-1 ), electrochemical stability window (> 4 V vs Li/Li+ ) and transport properties allowing them to be explored for commercial cathodes like LiFePO4. We hope to provide a promising direction for developing bio-derived solid electrolytes to facilitate progress in a sustainability, cost-effective and safe manner towards solid-state lithium batteries for global utilization.
Development of a Polymer-Based Silicon-NMC Solid-State Cell
Authors: Giffin Guinevere A. , Goettlinger Mara , Bohn Hendrik , Peters Simone , Weller Mario , Naßmacher Alexander , Brändel Timo , Friesen Alex
Published: February 2024

Solid-state batteries are seen as the next generation of battery technology with the promise of high energy density and improved safety as compared to conventional lithium-ion batteries. To achieve these goals, high-capacity negative electrodes, e.g., silicon or lithium, need to be combined with high capacity and high voltage positive electrodes, e.g., Ni-rich NMC. This combination of active materials provides a number of significant challenges for the solid-state electrolyte. If silicon is used as the anode active material, significant volume changes during lithiation/delithiation occur. These volume changes lead to a variety of problems including irreversible loss of lithium and eventual disintegration of the electrodes, resulting in capacity fade. Therefore, the electrolyte must be sufficiently elastic to buffer these changes. If Ni-rich NMC is used as a cathode active material, then the electrolyte must be stable at voltages up to at least 4.2 V. There are currently few, if any, electrolyte solutions that can address these challenges simultaneously.

In the ASTRABAT project, a silicon-NMC solid-state cell has been developed based on two tailored polymer electrolytes, which allows the specific challenges of each cell compartment to be addressed separately. A vinylidene fluoride copolymer-based electrolyte has been developed for use as a catholyte and a hybrid inorganic-organic polymer electrolyte as the anolyte. This work will report a characterization of both electrolytes, along with their electrochemical performance in solid-state half-cells and full-cells.
Synthesis and Characterization of Vitrimer-like Self-Healing Polymer Electrolytes for Lithium Metal Batteries
Authors: Barakat Carla , Jia He , Gohy Jean-François
Published: February 2024

Solid-polymer electrolytes have become crucially significant with the fast-expanding energy requirements in both the academic and industrial spheres due to their better safety and energy density compared to liquid electrolytes. Despite these encouraging possibilities, a few obstacles are associated with these electrolytes, chief among them being the limited charge transport via the solid electrode-electrolyte interface. Due to the difference in electrochemical potential between the electrode and the electrolyte, this obstruction initiates electrode-electrolyte interactions through electrode volumetric changes, interface reactions, and space charge layers.

One possible way to enhance the LIB performance could be by integrating a new class of covalent adaptable networks called vitrimers.

The self-healing, shape memory, recyclability, and reprocessibility properties of vitrimers, a class of covalent adaptable networks (CANs), are derived from a covalent molecular network that can change its topology through molecular rearrangements while maintaining the overall number of network bonds. In this manner, Li dendrites that might develop during battery cycling could be eliminated and the electrolyte-electrode contact could be restored by vitrimers.

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Si-Drive European Project: Developing Crosslinked Polymer and Composite Membrane Electrolytes for Lithium-Based Batteries
Authors: Falco Marisa , Gerbaldi Claudio , Saffirio Sofia , Smeacetto Federico
Published: February 2024

Currently the main application of lithium ion batteries is in portable electronics, but new emerging applications such as electric cars require lower cost, improved cycle life, sustainability, safety and energy density.

The ambition of Si-DRIVE European project is proposing next-generation batteries for electric cars built in Europe, designed to ensure recycling above 50%. Si-Drive battery will contain a Silicon anode, which has a high specific capacity, and a high voltage cathode without cobalt to reduce the cost and improve sustainability.

As an alternative to conventional organic solvents, ionic liquids have been widely investigated over the years, due to their excellent properties in terms of safety and stability.

The 1st generation of electrolytes for Si-Drive includes selected ionic liquids with high ionic conductivity and wide electrochemical stability. The 2nd generation of electrolytes combines the ionic liquids and the precursors of the polymer matrix in the formulation, in order to obtain crosslinked self-standing flexible films. The addition of ceramic super lithium ion conductors to obtain composite polymer electrolytes is also envisaged to improve the electrochemical stability window of the electrolyte.

Here we present several different polymer electrolytes and semi interpenetrating polymer networks encompassing ionic liquids and ceramic materials having ionic conductivity > 10 mS/cm at 20 °C, which can be in situ-deposited and crosslinked on top of the electrodes, and combined to form bi-layered electrolyte membranes to tune the compatibility with the electrode materials. The cycling performance with different positive and negative electrodes at ambient temperature is also demonstrated.

Acknowledgements:

The Si-DRIVE project has received funding from the European Union’s Horizon 2020 Research&Innovation programme, under Grant Agreement 814464.

References

J.-Y. Hwang, S.-T. Myung, Y.-K. Sun, Chem. Soc. Rev. 46, 3529-3614 (2017)

M. Falco, C. Simari, C. Ferrara, J.R. Nair, G. Meligrana, F. Bella, I. Nicotera, P. Mustarelli, M. Winter, C. Gerbaldi, Langmuir 35, 8210-8219 (2019)

M. Falco, L. Castro, J.R. Nair, F. Bella, F. Bardé, G. Meligrana, C. Gerbaldi, ACS Appl. Energy Mater. 2, 1600-1607 (2019)

M. Falco et al., Electrochem. Commun. 118 106807 (2020)

S. Saffirio, M. Falco, G.B. Appetecchi, F. Smeacetto, C. Gerbaldi, Journal of the European Ceramic Society, 42(3), 1023-1032 (2022).
Operando NMR Characterization of Cycled and Calendar Aged Si Anodes
Authors: Wang Evelyna , Rodrigues Marco-Tulio F , Key Baris
Published: February 2024

Replacing graphite anodes with Si anodes can greatly increase the capacity of current Li-ion batteries. Detailed characterization of Si lithiation reactions, solid electrolyte interphase (SEI) formation, and reversibility are therefore active areas of research. Solid-state nuclear magnetic resonance (NMR) spectroscopy is useful for characterizing different local environments within Si anodes as well as differentiating surface and bulk environments. Furthermore, non-invasive and non-destructive NMR methods can reveal metastable LixSi phases or SEI species forming on (dis)charge that may be too reactive to detect via ex situ methods. Here, we use an in situ and in operando NMR methodology to characterize full pouch cells comprising of Si anodes and NMC cathodes. We can observe changes in the relative amounts of Li in different environments within the same Si anode before/during/after charge & discharge and with various amounts of cycling or calendar aging using in situ 7Li NMR. The pouch cells used in our in situ NMR study are comparable to pouch cells made using mid- to large-scale fabrication methods as opposed to laboratory scale; in other words, challenges of cell-to-cell variability are minimized. We hypothesize “trapped” lithiated phases formed in the Si anode no longer contribute to electrochemical cycling and thus limit capacity in subsequent cycles/aging. We also characterized the SEI/surface species in situ with aging via 13C NMR measurements, identifying reactions of lithium silicides with electrolyte solvents and their subsequent decomposition.
The Research of Different Strategies to Enhance Coulombic Efficiency of Sn/SnOx Modified TiO2 As Anode Material in Lithium-Ion Battery By in Operando Analytical Techniques
Authors: Ho Cheng-Hsun , Shen Yu-Min , Huang Jow-Lay , Chang Chia-Chin
Published: February 2024

In recent years, electrochemical energy storage technologies had become global concerns due to the emergent need for electric vehicles and portable electronics. Recently, Lithium ion batteries cannot meet the requirements of gravimetric/volumetric energy density, rate capability, cycling stability, and safety in various applications. As one of the most promising anode materials for LIBs, titanium dioxide(TiO2) has received considerable attention due to its superior cycling stability, rate performance, low cost, environmental friendliness, and safety compared to traditional graphite anode. However, the major challenges of this material are poor electronic/ionic conductivity and poor theoretical capacity. In order to overcome this issue, our research has been modifying high-capacity material (e.g., Sn/SnOx) into TiO2 with an eye to promoting its capacity. Modifying Sn/SnOx into TiO2 reduces the impedance and increases the Li-ion diffusion rate. The Sn@TiO2 is synthesized by the chemical bath with Sn(BF4)2, HBF4, Na2S2O3 and TiO2 (rutile and anatase mixed phase) followed by annealing at different temperature. From the TEM and XRD results, we had successfully synthesized Sn@TiO2 core-shell structure. The table below shows that the serious fading problem of Sn@TiO2 during the first and second cycle. Active lithium loss(ALL) in the initial charge process causes irreversible capacity of LIBs due to the formation of unstable solid electrolyte interface (SEI) layer on the electrode surface. To solve the problem, pre-lithiation has been widely accepted as one of the most promising strategies to compensate for active lithium loss. Our group is about to trying various pre-lithiation techniques, such as electrochemical and chemical pre-lithiation and using in operando XRD/Raman to point out the mechanism of SEI layers. The ultimate goal would be giving out advantages and challenges of each one then finding out the optimal approach to improve cycling performance of tin-based anodes in lithium-ion batteries.

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Dilatometric Investigation of Si-Rich Contacting Anode Under External Pressure
Authors: Banifarsi Sanaz , Abdellatif Abdelaziz , Wohlfahrt-Mehrens Margret
Published: February 2024

Silicon with high abundance and high gravimetric capacity around 3579 mAh.g-1 at Li15Si4 fully lithiated state [1] is one of the attractive anode materials in lithium-ion batteries. Volume expansion of around 300% in the fully intercalated state is the Achilles’ heel of silicon, causing particle pulverisation, continuous formation of solid electrolyte interface (SEI), loss of electrical contact and capacity loss.[2] The use of silicon composite instead of pure silicon, [1,3] limited de/lithiation,[4] and boosting the electrical connection between particles by applying optimal external pressure[5] are practical solutions to mitigate these disadvantages. This study investigates the electrochemical performance and the dilatometric behaviour of a multilayer pouch cells (0.06 to 1.5 Ah) under the external mechanical pressure. Using 1/3 of the Si capacity in order to stabilise the electrochemical performance of a high silicon content anode (70 wt% Si). An irreversible electrode expansion of about 20% after 3 cycles of formation at 0.1C and a 75% electrode thickening after 200 cycles at 0.5C were observed.

References

[1] P. Li, H. Kim, S.-T. Myung, Y.-K. Sun, Energy Stor. Mater. 35 (2021) 550–576. https://doi.org/10.1016/j.ensm.2020.11.028.

[2] L.Y. Beaulieu, K.W. Eberman, R.L. Turner, L.J. Krause, J.R. Dahn, Electrochem. Solid-State Lett. 4 (2001) A137. https://doi.org/10.1149/1.1388178.

[3] P. Kargl, V. Drews, P. Daubinger, O. Schweighofer, M. Marinaro, G.A. Giffin, M. Wohlfahrt-Mehrens, A. Thaler, J. Power Sources 548 (2022) 232042. https://doi.org/10.1016/j.jpowsour.2022.232042.

[4] M.N. Obrovac, L.J. Krause, J. Electrochem. Soc. 154 (2007) A103. https://doi.org/10.1149/1.2402112.

[5] M. Göttlinger, P. Daubinger, W. Stracke, S. Hartmann, G.A. Giffin, Electrochim. Acta 419 (2022) 140354. https://doi.org/10.1016/j.electacta.2022.140354.

Acknowledgment

Funding of the project HysKaDi (03XP0321) by the German Federal Ministry of Education and Research (BMBF) is gratefully acknowledged.

Figure 1