bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorinated Graphene Fillers for High-Performance Solid-State Lithium Batteries
Authors: Panda Ananya , Patra Jagabandhu , Chang Jeng-Kuei
Published: February 2024

Solid-state batteries (SSBs) are expected to revolutionize the field of energy storage due to their superior safety and high energy density, which result from the use of lithium metal as the negative electrode. However, the development of solid-state electrolytes (SSEs), the key component of SSBs, is quite crucial. SSEs have high thermal stability, high mechanical strength, and a wide electrochemical window but lack enough ionic conductivity; which is one of the most challenging aspects. Incorporating suitable active or inert fillers in the solid polymer electrolyte matrix is one of several methods adopted to improve the ionic conductivity of pure polymer SSEs. Two-dimensional graphene-based fillers are a promising option as they provide a high surface area for creating an abundant interface with the polymer matrix creating a continuous pathway for lithium-ion transport and simultaneously their robust nature improves the mechanical strength of the electrolyte. Pristine graphene is electronically conducting in nature owing to the continuous sp2 carbon linkages, but the electronic conductivity can be suppressed by disrupting the sp2 bonds by heteroatom functionalization on the graphene. This study investigates the heteroatom functionalization of graphene to obtain various graphene-based fillers such as graphene oxide (GO), reduced graphene oxide (rGO), and fluorinated graphene oxide (FGO) and their effectiveness when introduced into a polymer SSE matrix for LiNi0.8Co0.1Mn0.1O2-based SSBs. FGO filler outperforms others in terms of ionic conductivity, thermal stability, enhanced electrochemical potential window, and compatibility of the SSE. The optimized ratio of FGO fillers in SSE demonstrates excellent electrochemical performance, enabling long-term Li plating/stripping with small overpotential and stable cycling of Li/ LiNi0.8Co0.1Mn0.1O2 full cells. This work highlights the notable potential of FGO materials in improving the comprehensive properties of polymer SSEs and promoting the applications of polymer SSEs in high-performance SSBs.
(Invited) Investigating Microstructural Effects of Composite NCM811 Cathodes on ALL-Solid-State Li-Ion Batteries Performance Under Low Operation Stacking Pressure
Authors: Wu Nae-Lih (Nick) , Liu Haowen , Thi Shiki
Published: February 2024

All-solid-state lithium-ion batteries (ASSLIBs) have been considered suitable alternatives to commercial lithium-ion batteries (LIBs) in the aspect of safety issues that come from the use of inflammable solid electrolytes to replace organic flammable electrolytes. Nevertheless, there apparently remains much room for a better understanding of their properties and behaviors in order to upgrade their performance to reach the practical application level. Ni-rich layered oxides, LiNi1-x-yCoxMnyO2 (NCM), are promising cathodes for high-energy ASSLIBs because of their high capacities and redox potentials, and low material cost when compared with conventional LiCoO2. However, certain challenges associated with their use in ASSLIBs must be addressed for their effective use and industrialization. In particular, the structural integrity of the NCM electrodes during the long-term charge/discharge process suffers from the formation of an intergranular and/or intragranular cracking behavior. These microcracks are initiated at the grain boundaries from the anisotropic chemical strain of the randomly oriented polycrystal (PC) primary cathode particles. Solid evidence behind the electrochem-mechanical breakdown of an NCM cathode with liquid electrolytes has been well discussed and reported in the literature. However, the breakdown in ASSLIBs may not obey as same as in the liquid-electrolyte LIBs and display exclusive mechanics-oriented material damage in the presence of rigid solid-state electrolytes (SSEs). The primary objective of this research is to gain a deeper understanding of various cracking modes in ASSLIBs, which we believe is instrumental to improving the lifespan and cell performance as a whole. ForASSLIBs, stacking pressures greater than 100 MPa under battery operation are currently commonly used. The use of high stacking pressure increases manufacturing and usage difficulties and overall cost. Lowering the battery-operation stacking pressure, for example to the level of the liquid-electrolyte batteries, will certainly facilitate the wider applications of ASSLIBs. In this context, composite cathodes consisting of a LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and brittle Li3InCl6 (LIC) SSE have been assessed for ASSLIB applications under low operation stacking pressure (coin-cell configuration; ~2.0 MPa). The study reveals the effects of material and structural characteristics of the composite cathode, including the NCM particle size and size distribution, active-material spatial distribution, particle crystallinity (polycrystal or single-crystal), and electrochemical operation parameters (voltage range, current rates) on the cycle stability of the ASSLIBs as a result of the electrochem-mechanical behaviors of the oxide cathode. Meanwhile, a novel solvent-based synthesis process of LIC for achieving high-density cathodes is introduced.
Ni-Rich Cathode Active Materials Surface Degradation in Ambient Air with Stabilisation Treatment Proposal
Authors: Galantowicz Joanna Maria , Coulbeck Elliot , Tallant Neil , Simmons Mark , Kendrick Emma
Published: February 2024

Ni-rich cathode active materials, such as NMC811 (Li[Ni0.8Mn0.1Co0.1]O2), are promising cathode materials due to their higher theoretical capacity of 200mAh/g, lower cobalt ratio, and overall decreased material expenses. However, the material undergoes a phase transition from layered ( ) through spinel ( ) to rock salt ( ) at high state of charge with oxygen release, and formation of rock salt structures on the surface with lithium carbonates and lithium hydroxides (Residual Lithium Compound (RLC)) while material is exposed to ambient air, all of which is followed by an increase in surface impedance and a decrease in final battery performance.

Here, we explore the chemical and electrochemical evaluation of the Ni-rich cathode active material surfaces when exposed to ambient air for fourteen days (RH~40%). The combination of Fourier-transform infrared spectroscopy (FT-IR) and electrochemical impedance spectroscopy (EIS) will be investigated. These complementary non-destructive approaches will be utilised to characterise the decomposition of the original layered surface and formation of RLC. In addition, the research will be evaluated using STA, XRD, formation, diffusion coefficient, and cycle life in a half-cell using lithium-ion discs as counter electrodes. Furthermore, we show a technique for stabilising the material in air using Experimental ElectroRite®1 Additive provided by Lubrizol Ltd. which reduces the formation of the RLC and the corresponding surface phase changes, often attributed to the presence of Ni2+ ions. This work contributes to a greater understanding of the surface stabilisation through chemical treatment required and suggests routes to create stable water-based Ni-rich cathode inks.
Operando High-Temperature X-Ray Absorption Spectroscopy of LiNiO2 Cathode Material during Synthesis
Authors: Kubota Kei , Ichihara Fumihiko , Masuda Takuya
Published: February 2024

The increasing demand for higher energy density in batteries for automotive applications has led to a trend toward increasing the Ni content in layered oxide cathode materials to increase their reversible capacity. However, LiNiO2, which has the highest Ni content, shows a faster capacity drop during charge-discharge cycling, which is attributed to its inherent structural instability in both the pristine and delithiated states. Therefore, to address the former issue and to better understand the appropriate synthesis conditions for LiNiO2, we have studied the changes in the local structure of LiNiO2 during the synthesis process using operando analysis techniques.

Recently, high temperature in situ X-ray diffraction during LiNiO2 synthesis was reported by Bianchini [1] and Weber [2], which confirmed the loss of lithium and oxygen and the migration of Ni to Li layers above 700 °C. To further understand the mechanism of Li/Ni mixing and oxygen loss, operando high-temperature X-ray absorption spectroscopy (XAS) was performed during the synthesis of LiNiO2 to clarify the electrical structure of Ni at high temperatures.

Pre-heated Li
x
NiO2 (x = 0.76, 1.01, 1.26, and 1.51) precursors were prepared by heating LiOH·H2O and Ni(OH)2 at 480 °C for 24 h in air. The precursor was pelletized and set in a quartz sample holder. Operando high-temperature Ni K-edge XAS spectra of the precursor were obtained at BL9A and BL12C in Photon Factory (PF), High Energy Accelerator Research Organization (KEK) by a transmission mode. The operando spectra of all samples except Li/Ni = 0.76 revealed a clear edge shift to the lower energy side corresponding to nickel reduction above 700 °C. The Li/Ni = 0.76 sample has a lithium-deficient composition and Ni is not oxidized to Ni3+ below 700 °C, so the Li/Ni = 0.76 sample has almost no Ni K-edge energy shift above 700 °C. These results suggest that Ni in LiNiO2 is reduced above 700 °C even in an oxygen atmosphere, regardless of whether the Li/Ni ratio is greater than 1. The Ni reduction above 700 °C is probably the cause of the Li/Ni mixture.

Reference

[1] M. Bianchini, J. Janek, et al., Angew. Chem., Int. Ed., 58, 10434 (2019).

[2] R. Weber, J. R. Dahn, et al., J. Electrochem. Soc., 167, 100501 (2020).
Development of Graphite Anodes from Coal Derived Carbon
Authors: Paul Abigail , Magee Regan , Wilczewski Warren , Wolfe Kody D , Wichert Nathan , Wang Fengkun , Trembly Jason , Staser John A. , Garrick Taylor R.
Published: February 2024

As demand for energy storage expands, securing reliable supply-chains for raw battery materials is critical in mitigating the threats of delayed manufacturing and inflated manufacturing costs. These issues have pushed researchers and industry to consider alternative sources for traditional lithium-ion battery materials, such as graphite. Commonly available sources of graphite for Li-ion anodes include natural graphite and petroleum coke derived synthetic graphite. While many carbon sources have been studied, most require complicated processing and result in sub-par graphite anode materials. This talk highlights raw coal and coal derived materials as promising graphite sources thanks to their abundance of sp2 hybridized carbon, resulting in simpler processing, and low material costs.

We show that coal derived graphite can be implemented as a lithium-ion anode, however, many chemical, microstructural, and morphological considerations are necessary to compare with commercial graphite performance. Key topics of this talk include i) the processing steps necessary for achieving high-performing coal-derived graphite, ii) chemical, microstructural, and morphological graphite characterization, and iii) comparative performance of coal-derived graphites and commercial graphite as lithium-ion anodes. Characterization of the anodes’ performance includes gravimetric capacity, initial capacity loss, coulombic efficiency, internal resistance, intercalation energetics, and pseudo-open circuit potential characterization. Emphasis is placed on the careful consideration and effects of fundamental anode properties (particle size, surface area, etc.) because they are crucial in determining the viability of alternative graphite sources for lithium-ion battery anodes.
Ultra-High Energy Density LiFePO4 Electrodes
Authors: Syed Moarij , Obrovac Mark
Published: February 2024

Olivine structured LiFePO4 (LFP) has attracted significant attention as a promising cathode material for LIBs. An advantage of using LFP compared to other cathode chemistries (i.e., NMC, LCO & LNO) is that iron is naturally abundant, making LFP low in cost, environmental impact, and toxicity.1,2 Though LFP has high thermal stability and excellent cycle life, it suffers from poor electronic conductivity and low Li+ ion diffusion which have been improved by carbon coating and reducing particle sizes to nanometres (<1 µm), respectively.3

To improve the energy density of LFP electrodes we have developed ultra-dense LFP electrodes with densities in excess of 2.7 g/cm3 to be achieved with high loadings (15 mg/cm3) and with electrode formulations containing 90% LFP active material. This corresponds to an electrode porosity of only 14% and, as shown in Figure 1(a), represents a volumetric energy density increase of about 27% compared to conventional LFP. Moreover, as shown in Figure 1(b), ultra-high density LFP electrodes were found to have higher coulombic efficiency than conventional calendered LFP electrodes with lower densities. Voltage polarization was also found to be reduced. Lastly, Figure 1(c) shows an approximate 4 times reduction in charge transfer resistance for an ultra-dense LFP electrode with respect to a conventional calendered LFP electrode. The ability to make highly dense LFP electrodes could have profound impacts, allowing for Li-ion cells to be made with low costs and low environmental impact LFP, while achieving volumetric energy densities approaching that of Li-ion cells employing layered oxide cathodes.

References

X. Ren et al., J. Electrochem. Soc., 167, 130523 (2020).

L. Wen, X. Hu, H. Luo, F. Li, and H. Cheng, Particuology, 22, 24–29 (2015).

L.-X. Yuan et al., Energy Environ. Sci., 4, 269–284 (2011).

Figure 1
Electrochemical Synthesis of Nano-Structured Si and Graphene Composite for Li Ion Battery
Authors: Patel Yashkumar , Vanpariya Anjaliben , Mukhopadhyay Indrajit
Published: February 2024

The application of lithium-ion batteries is widespread across a variety of sectors, such as portable electronic gadgets, mobile phones, new electric car batteries, and many others. Silicon–Graphene (SiG) anodes are among the sophisticated anode materials that have been used in lithium-ion batteries. These anodes have been widely researched because of their high capacity, strong operating potential, environmental friendliness and great abundance. SiG anodes have shown a lot of promise as a potential anode material for lithium-ion batteries [1]. This is due to the fact that they have solved many issues that were present in Si anodes, including particle pulverization, shedding and failures of electrochemical performance during lithiation and delithiation. Nevertheless, there are still certain issues that need to be improved, such as low initial discharge efficiency, poor conductivity and poor cycle performance. This research focuses on presenting a unique approach that may be used to address the issues associated with Si anode materials. An electrodeposition method that only needs a single unit operation, is applied in the process of constructing composites of SiG from G-1M SiCl4 in [BMIm]Tf2N ionic liquid (IL) [2]. In SiG composites, both silicon and graphene have been seen to have a layered structure (Fig.1 a). The SiG anode displays a specific charge/discharge capacity of 1133/ 2272 mAhg-1 at the first cycle and it drops to 676/ 737 mAhg-1 at the conclusion of 100 cycle at 0.2C (Fig.1b), which demonstrates a robust cycle ability at a moderate rate. The present work will thus discuss on the development of SiG composite by electrochemical method for its utility as negative electrode material in Li ion battery.

References:

Huang, Z. et al. Binder-free graphene/carbon nanotube/silicon hybrid grid as freestanding anode for high capacity lithium ion batteries. Compos. A 84, 386–392 (2016).

Anjali Vanpariya, Kashinath Lellala, Dharini Bhagat, Indrajit Mukhopadhyay*, Electrochemical deposition of Si nano-spheres from water contaminated ionic liquid at room temperature: Structural evolution and growth mechanism, J. Electroanal. Chem., 910 (2022) 116175-116181.

Figure 1
Microstructural Refinement and Surface Modification of Ni-Rich Cathodes for High-Performance Li-Ion Battery
Authors: Kim Myoung-Chan , Hwi Kim , Sun Yang-Kook
Published: February 2024

Li[Ni1–x–y–zCoxMnyAlz]O2 (NCMA) cathodes have attracted public attention owing to their improved durability by leveraging the advantages of NCM and NCA cathodes. The combination of Mn and Al in a NCMA cathode effectively stabilizes the host layered structure to increase its resistance to microcracking; consequently, NCMA cathodes outperform both NCM and NCA cathodes with the same Ni contents, in terms of cycle life, without sacrificing energy density. However, as the Ni contents of the cathodes exceed 90%, a simple, compositionally engineered NCMA cathode lacks the chemical and mechanical stability to suppress surface degradation and the development of permanent microcracks due to the high incidence of highly reactive Ni4+ species on its surface.1,2 Considering the limitations of NCMA cathodes, a combination strategy involving microstructural engineering to inhibit microcracking, by enabling the efficient dissipation of local strain,3 and the modification of the exposed cathode surface, to protect it against deleterious electrolyte attack, is expected to afford superior Ni-rich layered cathodes.

In this study, we improved the cycling stability of a conventional NCMA cathode with a Ni content of 93% (a NCMA93 cathode) using a combination strategy involving microstructural engineering and surface modification. To this end, we prepared a Sb-doped NCMA93 (denoted as Sb-NCMA93) cathode; Sb was incorporated to refine its microstructure and radially align and elongate its primary particles. Furthermore, we generated a protective F layer on the cathode surface through a chemical reaction between residual lithium compounds and a NH4F coating agent. To comprehensively investigate the synergetic effect of this combination strategy, conventional and Sb-doped NCMA93 cathodes with and without F coatings were synthesized and characterized and their fundamental properties and electrochemical performances compared. Post-mortem analyses were performed to elucidate the origins of the remarkable long-term cycling stability of the optimized cathodes.

Reference
s
:

[1] H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources, 2013, 233, 121.

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

[3] 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.
Investigation of the Solid Electrolyte Interphase of Silicon Wafers Using a Fluorine-Free Electrolyte
Authors: Patranika Tamara , Edström Kristina , Hernández Guiomar
Published: February 2024

Lithium-ion (Li-ion) batteries have become an important solution for energy storage owing to their high gravimetric and volumetric energy density. The electrolyte solution of the battery has a large effect on the stability and performance of the cell. During the first cycles of a battery, the solid electrolyte interphase (SEI) layer is formed due to the degradation of the electrolyte. Hence the composition of this layer, and the stability, are dependent on the electrolyte composition.

The most commonly used electrolyte for Li-ion batteries is the salt lithium hexafluorophosphate LiPF6 dissolved in organic solvents together with additives, both containing fluorinated compounds.1 However these fluorinated compounds are susceptible to release HF which is toxic and corrosive which could be detrimental for the cell performance but also hinder the recycling process. Therefore, fluorine-free electrolytes could be a promising alternative. While this type of electrolytes has been investigated with graphite anodes, when moving to higher energy densities, such as silicon, their performance and degradation mechanism is not yet clear.2

Previous research has shown increased stability for Li-ion batteries using a fluorine-free electrolyte based on the salt lithium bis(oxalato) borate (LiBOB).2 Furthermore, operando X-ray reflectometry (XRR) measurements on silicon wafers half-cells with the same electrolyte have shown the build-up of multiple layers on the anode, providing the thicknesses and densities of the different layers. This work presents the chemical composition of these different layers formed on the silicon wafers at different potentials when using a fluorine-free electrolyte based on LiBOB in ethylene carbonate and methyl ethyl carbonate. These results are also compared with the effect of adding vinylene carbonate VC as an additive. The different components in these layers are correlated to the previous XRR data to explain the SEI-formation mechanism with fluorine-free electrolytes.

Xu, K. Nonaqueous liquid electrolytes for lithium-based rechargeable batteries. Chem Rev
104, (2004).

Hernández, G. et al. Elimination of fluorination: The influence of fluorine-free electrolytes on the performance of LiNi1/3Mn1/3Co1/3O2/silicon-graphite li-ion battery cells. ACS Sustain Chem Eng
8, (2020).
Liovix® Printable Lithium Technology for Controlled and Scalable Prelithiation of Silicon Anodes
Authors: Fitch Brian , Yakovleva Marina , Xia Jian
Published: February 2024

Loss of active lithium in the first cycle permanently lowers the lithium-ion cell energy density. Prelithiation employs an external, sacrificial source of lithium to offset these losses allowing more efficient use of lithium from the cathode and raising the cell energy density.

LIOVIX®printable lithium technology is comprised of stabilized lithium metal powder (SLMP®) dispersed in a compatible solvent along with other rheology and performance modifiers to create a formulation that is chemically stable and not prone to separation for extended periods of time. The technology is easily scalable using industry standard coating and printing equipment to apply the formulation to the surface of a prefabricated anode. LIOVIX® can be used in anodes with a range of silicon content, because lithium loading can be accurately controlled based on the applications’ requirements.

In this presentation, we will compare LIOVIX® to other prelithiation methods. The electrochemical results will be discussed as well.
Influence from Mechanical Stress on State of Health of Large Prismatic Lithium-Ion-Cells Under Various Temperatures
Authors: Petursdóttir Erla , Kohlhuber Markus , Ehrenberg Helmut
Published: February 2024

Volume expansion of lithium-ion cells is a well-known ageing phenomenon, in which the outer and inner geometry of the cell is subject to deformation due to physicochemical reactions during ageing and operation, resulting in corresponding degradation effects such as loss of capacity and higher internal resistance in the cell. In a cell module the external deformation of the cells poses a major challenge to the mechanical design due to the resulting swelling forces.

In this work, compression force and thickness measurements were performed on large prismatic lithium-ion cell with various compression magnitudes to quantify the influence of mechanical stress on state of health of the cells. The impact of the bracing is shown for lithium-ion cells cycled with 1C constant current constant voltage charge and 1C constant current discharge up to 500 cycles with 100% depth of discharge and at every 50 cycles, the capacity of the cells was determined, and electrochemical impedance spectroscopy measurements were conducted. The cells were cycled until the threshold of 80 % state of health was reached. In-situ thickness measurements showed cell expansion during charging and contraction during discharging due to lithiation as well as de-lithiation additionally the measurements showed an irreversible thickness change in the cell due to ageing phenomenon. To quantify the increase in internal resistance a distribution of relaxation time (DRT) analysis was performed on the electrochemical impedance spectroscopy (EIS) data.
Effect of Electrolyte Additives on the Performance of 18650 Cylindrical Ni-Rich Li-Ion Battery Cells
Authors: Nanthamitr Puttida , Sangsanit Thitiphum , Tejangkura Worapol , Sawangphruk Montree
Published: February 2024

Ni-rich Li-ion batteries have gained a lot of attention in recent years due to their high energy density and low cost. However, these batteries also face some challenges such as poor cycle life, capacity fading, and safety concerns. One way to overcome these issues is by modifying the electrolyte composition through the addition of various additives. Electrolyte additives can affect various aspects of the battery's performance, including its capacity, cycle life, and safety. For example, the addition of certain electrolyte additives can increase the stability of the cathode material, leading to improved cycle life and capacity retention. Other additives can enhance the thermal stability of the battery, which is important for preventing thermal runaway and improving safety. One commonly used electrolyte additive is fluoroethylene carbonate (FEC), which has been shown to improve the cycle life of Ni-rich Li-ion batteries by forming a protective layer on the surface of the cathode material. Another additive, vinylene carbonate (VC), can improve the stability of the electrolyte interface and prevent the decomposition of the electrolyte at high voltages.
Harmonization of Testing Procedures for All Solid State Batteries
Authors: Lee Yan Ying , Weber Andre
Published: February 2024

All Solid State Batteries (ASSBs) with lithium-ion based conducting solid state electrolytes are considered the next generation high performance batteries. They enable high power densities due to their single ion conducting solid electrolyte, eliminating salt concentration gradients and related polarization losses in the cell, and ensuring an unrivalled level of safety due to their non-combustibility. Currently, a variety of ASSBs based on different solid state electrolytes such as polymers, thiophosphates, oxides and combinations thereof are being developed.

One general problem with ASSBs is establishing and maintaining contact between the solid electrolyte and the active material phase during production and cycling, respectively. In conventional lithium-ion batteries (LiBs), this contact is ensured by the liquid state of the electrolyte, but in ASSBs, chemical expansion and contraction of the active material during lithiation and delithiation can detach this contact, resulting in decreased capacity due to the loss of active material. As a consequence, ASSBs are often operated under pressurized conditions, applying pressures significantly exceeding those in conventional LiBs. The same holds for the operating temperature window. Especially for polymer electrolyte-based ASSBs, they are often operated at higher temperatures to compensate for the low ionic conductivity of polymers at room temperature. With respect to cell testing, such operating requirements must be considered, and testing protocols are designed according to the individual requirements of the tested cell.

This contribution aims to provide an overview of testing protocols for various types of ASSBs applied to different cells with polymer-, thiophosphate-, oxide-, and hybrid-electrolytes. These protocols will be compared with standardized testing routines for conventional LiBs. Based on this compilation, a harmonized testing procedure that covers the special requirements of the individual cell types and enables a fair comparison of different ASSBs is suggested. Additionally, examples of ASSB testing results will be discussed, taking into consideration the harmonization of different testing parameters.
Improving Lithium-Ion Batteries By Replacing Polyethylene Terephthalate Jellyroll Tape
Authors: Adamson Anu , Bötticher Tom , Tuul Kenneth , Garayt Matthew D. L. , Azam Saad , Metzger Michael
Published: February 2024

Every lithium-ion battery cell produced today that is either wound or stacked contains tape. This tape serves the mechanical purpose of holding together the wound jellyroll or stacked electrodes before inserting it into the cell casing, after which the tape serves no purpose. Battery manufacturers often test inactive cell parts for their physical parameters, i.e., elongation, water absorption, and temperature resistance.1 However, their chemical stability is often overlooked. Recently, it was demonstrated that polyethylene terephthalate (PET) tape can partially dissolve in the harsh lithium-ion battery cell chemistry into its monomer dimethyl terephthalate (DMT). This molecule can act as an unwanted redox shuttle in LFP/graphite or NMC811/graphite cells, inducing self-discharge of the battery.2

Figure 1 shows Fourier-transform infrared (FTIR) spectra of tapes obtained from discarded cellphone batteries. Many well-known lithium-ion battery producers use PET tape in their products. In addition, the FTIR spectra show that after the cells have been cycled, the surface layer of these tapes is severely corroded. This study will show open circuit storage, Ultra-High Precision Coulometry, and long-term cycling results from LFP/graphite cells with PET tape. The study will also show how swapping PET tape for a more stable alternative can significantly improve the performance and reduce the self-discharge of LFP/graphite pouch cells.

Figure caption:

Figure
1
. FTIR spectra of jellyroll closing tapes (a) extracted from discarded cellphone batteries (b).

References:

E. Foreman et al., Adv. Sustainable Syst., 1, 1700061 (2017).

S. Buechele et al., J. Electrochem. Soc., 170, 010511 (2023).

Figure 1
Solvent-Free Lithium-Ion Batteries to High Volumetric Capacity via Carbon Nanotube-Coated Ni-Rich Cathodes
Authors: Koo Jin Kyo , Ha Chaeyeon , Seo Jae kwon , To-a-ran Weerawat , Kim Young-Jun
Published: February 2024

Until now, lithium-ion battery production technology relied on a slurry-based process using organic solvents (NMP), which is hazardous and is a major contributor to high cost and energy consumption in battery manufacturing processes. Among many studies to reduce battery costs, the dry electrode process that does not use organic solvents is attracting attention as a rising star. Dry electrode technology is one of the most promising processes for next-generation energy storage systems due to their eco-friendly production and lowering energy costs (US$ kWh−1). However, when nano-sized carbon black (CB) is used in a dry electrode process, electrochemical performance deteriorates due to insufficient conductivity in the electrode due to pin-point contact with the nickel-rich cathode. In addition, when CNTs used in the conventional wet process are applied to a dry electrode process, it is still difficult to prepare a dry electrode that is uniformly distributed within the electrodes due to its very high aggregation properties. Despite having innovative advantages, solvent-free processing remains a challenge due to these critical issues. Here, we fabricated a dry-type electrode by using poly-crystalline Ni-rich cathodes uniformly coated with CNTs (Carbon nanotubes), resulting in higher electrical conductivity than the electrodes prepared with the conventional wet process including carbon black (CB). In addition, as a result of minimizing the amount of PTFE binder in the electrode by eliminating the mixing of existing carbon black (CB), dry electrode manufacturing was enabled without crushing the Ni-rich cathodes even the fabrication of dense cathodes with extremely high active material content (99.7%) and high electrode density (4.0 g cm-3). The CNT-coated dry electrodes show a high Qvol of ~860 mAh cm-3 at a current rate of 0.2 C (~1.0 mA cm-2) compared to the conventional wet-process electrodes (98 wt% Ni-rich cathode; ~3.6 g cm-3). Furthermore, to demonstrate the practical LiBs operation, a 12cm2-sized pouch cell (>60mAh) was fabricated via dry process and exhibited excellent cycle performance (up to 80% after 400 cycles). We believe that this solvent-free lithium-ion battery via carbon nanotube-coated Ni-rich cathodes approach would be feasible and bring a new electrode design paradigm to the lithium-ion battery market.

Figure 1
Ionogels Based on Dynamically Cross-Linked Polyrotaxanes and Ionic Liquids for Lithium-Ion Batteries
Authors: Yan Shanshan , Jia He , Gohy Jean-François
Published: February 2024

While liquid electrolytes are known for their inherent safety issues and solid polymer electrolytes suffer from their low ionic conductivity and high interfacial resistance at room temperature, ionogels combine the advantages of liquid electrolytes in terms of ionic conductivity and display acceptable mechanical properties compared to solid polymer electrolytes. Here, dynamically cross-linked poly(rotaxane) networks have been obtained by introducing dynamic and anion capturing centers based on boronic esters. Those networks have been further swelled by ionic liquids in order to obtain ionogels displaying superior ionic conductivities of 2.21×10−
3 S/cm at room temperature and a wide electrochemical stability window up to 4.8 V (vs. Li+/Li). In addition, those ionogels show high transference number for lithium ions because of the presence of the boron anion capturing groups. They also show the higher interfacial stability with lithium metal. When those ionogels are combined with a high voltage cathode LiNi0.6Co0.2Mn0.2O2, (NCM622), the resulting NCM622||ionogel||Li cell delivers superior discharge capacity at 0.1 C at room temperature, which is close to the theoretical capacity (170 mAh g−1) of NCM622. The cell also exhibits remarkable rate and cycling performance. This work demonstrates that the combination of ionogels and high-voltage cathode provides excellent electrochemical performance for the resulting batteries.
Nonflammable Gel Polymer Electrolyte for Lithium-Ion Batteries with Enhanced Safety and High-Temperature Performance
Authors: Lim Da-ae , Shin Young-Kyeong , Seok Jinhong , Hong Dayoung , Lee Chul Haeng , Ahn Kyoung Ho , Kim Dong-Won
Published: February 2024

Lithium-ion batteries (LIBs) have become dominant power sources for various applications such as mobile electronics, electric vehicles and energy storage systems. However, liquid electrolytes currently used in LIBs have critical drawbacks such as flammability and leakage problem. In this regard, various electrolyte systems have been developed to enhance the battery safety while maintaining cycling performance. Among them, the chemically cross-linked gel polymer electrolytes (GPEs) can enhance the thermal safety of LIBs by effectively encapsulating organic solvents in the polymer matrix. However, they usually contain large amounts of organic solvents to achieve high ionic conductivity, making GPE be still flammable. To solve these problems, we designed and synthesized a novel phosphorus-based cross-linking agent with excellent flame retardancy. GPE was prepared by in-situ thermal curing of gel precursor containing liquid electrolyte and phosphorus-based cross-linking agent. The obtained GPE exhibited high ionic conductivity and nonflammability. The GPE was applied to lithium-ion cells composed of graphite anode and LiNi0.6Co0.2Mn0.2O2 cathode. Our results revealed that the lithium-ion cell employing GPE exhibited enhanced safety and improved high-temperature cycling performance compared to the cell with the liquid electrolyte.
Unraveling the Lithium Storage Mechanism at Low Potentials in Niobium Pentoxide Anodes for Lithium-Ion Batteries
Authors: Xue Xilai , Asenbauer Jakob , Eisenmann Tobias , Dinda Sirshendu , Lepore Giovanni Orazio , Xing Silin , Mullaliu Angelo , Diemant Thomas , d'Acapito Francesco , Parac-Vogt Tatjana N. , Fichtner Maximilian , Tübke Jens , Bresser Dominic
Published: February 2024

State-of-the-art lithium-ion anodes based on graphite exhibits high specific capacity and a low de-/lithiation potential, thus, enabling very high energy densities at full-cell level. However, the rather sluggish lithiation kinetics render them less suitable for fast-charging batteries[1]. A potential alternative that has gathered increasing interest in recent years is Nb2O5, but the commonly employed lower cut-off voltage of 1.0 V vs. Li+/Li in combination with the lower capacity compared to graphite limit the achievable energy density[2,3].

Herein, the extended lithiation to lower cut-off voltages is reported, resulting in increased capacities while maintaining a very stable cycle life. Remarkably, this behavior is generally independent from the initial polymorph, and both monoclinic and orthorhombic Nb2O5 show a substantial increase in capacity for several hundred cycles. To elucidate the underlying storage mechanism, comprehensive characterization via operando/ex-situ X-ray diffraction (XRD), operando Raman spectroscopy, operando isothermal microcalorimetry (IMC), ex-situ X-ray absorption spectroscopy (XAS), and ex-situ X-ray photoelectron spectroscopy (XPS) was conducted. It appears that the occurrence of an additional phase transition at low potentials plays a decisive role for the enhanced capacity and superior cycling stability.

Reference

[1] J. Asenbauer, T. Eisenmann, M. Kuenzel, A. Kazzazi, Z. Chen, D. Bresser, Sustain. Energy Fuels
2020, 4, 5387–5416.

[2] P. Jing, K. Liu, L. Soule, J. Wang, T. Li, B. Zhao, M. Liu, Nano Energy
2021, 89, 106398.

[3] T. Li, G. Nam, K. Liu, J. H. Wang, B. Zhao, Y. Ding, L. Soule, M. Avdeev, Z. Luo, W. Zhang, T. Yuan, P. Jing, M. G. Kim, Y. Song, M. Liu, Energy Environ.
Sci.
2022, 15, 254–264.
Tortuosity Effect of Graphite Anodes for High-Performance Cylindrical Li-Ion Batteries
Authors: Joraleechanchai Nattanon , Sangsanit Thitiphum , Homlamai Kan , Krapong Purin , Sawangphruk Montree
Published: February 2024

This study aimed to investigate the impact of graphite tortuosity at the practical thick electrode level, which is complex and not yet well understood, on the electrochemical performance of Ni-rich NCA90 Li-ion batteries (LIBs). Various graphite anode tortuosities were examined, and it was found that low-tortuosity electrodes demonstrated better graphite utilization than high-tortuosity electrodes. In operando X-ray Diffraction and Differential Electrochemical Mass Spectrometry were also employed for charge storage mechanism and gas evolution detection, respectively. We have found that the tortuosity of the graphite electrode had an impact on the amount of Li present in the lithiated graphite phase due to diffusion limitations. However, graphite tortuosity did not have an influence on gas generation during battery operation. Safety testing conducted according to UN38.3 confirms all batteries produced in this work are safe. The study eventually demonstrated the practical use of NCA90 LIB cells optimized with varying tortuosities of thick graphite electrodes in a high-performance Lamborghini GoKart. By integrating fundamental research with practical demonstrations, this investigation is expected to contribute to further advancements in Ni-rich LIB technology.
Cleaning up Operando Battery X-Ray Diffraction with Total Scattering Computed Tomography
Authors: Wragg David Stephen
Published: February 2024

Operando X-ray diffraction (XRD) and total scattering investigations of battery electrode materials allow us to relate structure and electrochemical properties down to the atomic level. By studying the materials under real working conditions without allowing the materials to relax or react outside the battery, we obtain the most reliable possible structural information. Unfortunately, in most operando experiments, even when we use heavily modified cells to remove barriers to our probe radiation, the signal from the material of interest is significantly obscured by contributions from other battery components. The problems are increased when we seek to study electrode materials which either are, or become, amorphous during battery cycling: removing non-sample contributions is an essential part of pre-processing total scattering data for pair distribution function (PDF) analysis, which can reveal the local structures of non-crystalline materials.

To address these problems, we have developed operando total scattering computed tomography (TSCT) as a method for obtaining clean, 5-dimensional (3-D space, time, and chemical structure) information on working batteries. The method allows us to select specific areas of the active electrode and obtain XRD and PDF information without any contributions from other components of the battery. The high-quality of the resulting data has allowed us to understand the cycling mechanisms of poorly scattering, amorphous, alloying anode materials (sodium cycling in phosphorus)[1], and complex, multi component, conversion-alloying systems (lithium cycling in bismuth vanadate)[2]. While the first example mainly uses the focusing power of TSCT to obtain the best possible data, the latter case uses the spatial resolution of the data to identify signs of a longer-term deactivation mechanism based on agglomeration of the nanoclusters of active material during repeated cycling. Further studies are currently in progress to apply the method to other difficult anode systems including silicon.

[1] J. Sottmann, M. Di Michiel, H. Fjellvåg, L. Malavasi, S. Margadonna, P. Vajeeston, G.B.M. Vaughan, D.S. Wragg, Chemical Structures of Specific Sodium Ion Battery Components Determined by Operando Pair Distribution Function and X-ray Diffraction Computed Tomography, Angew. Chem. Int. Ed. 56, pp. 11385-11389, 2017

[2] J. Sottmann, A. Ruud, Ø.S. Fjellvåg, G.B.M. Vaughan, M. Di Michel, H. Fjellvåg, O.I. Lebedev, P. Vajeeston, D.S. Wragg, 5D total scattering computed tomography reveals the full reaction mechanism of a bismuth vanadate lithium ion battery anode, Phys. Chem. Chem. Phys. 24, pp.27075-27085, 2022

Figure 1
Microwave-Irradiation Suppresses the Jahn-Teller Distortion in Spinel LiMn2O4 Cathode Material for Lithium-Ion Batteries
Authors: Tsekeli Tebogo Retsepire , Haruna Aderemi Bashiru , Ozoemena Kenneth Ikechukwu
Published: February 2024

Jahn-Teller (J-T) distortion remains the key challenge to realizing the full electrochemistry potential of the commercialized LiMn2O4 cathode material for lithium-ion batteries. In this work, the application of microwave irradiation to suppress the limiting J-T distortion in pristine LMO (LMO-p) materials and improve the electrochemistry of lithium-ion batteries has been reported. Unlike thermal heating, microwave irradiation inhibits J-T distortion. To establish the underlying science behind the impact of microwave irradiation, both the pristine (LMO-p) and the microwave-treated counterpart (LMO-m) are subjected to several characterization techniques, including synchrotron XRD, XPS, powder neutron diffraction (PND), MAS 7Li NMR, Raman and BET analysis. These techniques prove that LMO-m possesses the needed physico-chemical properties that explain: i) suppressed J-T distortion (such as an increased average Mn oxidation state (i.e., nMn ≥ 3.5+ or Mn4+/Mn3+ > 50%)), decreased lattice parameter, enhanced BET surface area, and enhanced structural crystallinity), and ii) improved electrochemical performance (such as increased specific discharge capacity, electronic and Li-ion transfer kinetics, and Coulombic efficiency). The findings in this work are relevant for the realization of low-cost and environmentally benign scale-up modification processes for LMO spinel and related cathode materials for the development of high performance lithium-ion batteries.
Modulating the Product Distribution of the Electrochemical Reduction of CO2 on Copper at Relevant Current Densities
Authors: Parada Villarroel Walter Agustin , Sajevic Urban , Peirow Asfia Mohammad , Nikolaienko Pavlo , Mayrhofer Karl J. J.
Published: February 2024

The electrochemical reduction of CO2 (CO2RR) has the potential to be an economically-viable method to produce platform chemicals synergistically with renewable energy sources. Copper is one of the most used electro-catalysts for this purpose, as it allows carbon-carbon bond formation, crucial for broader product distribution. Despite great achievements, controlling selectivity is yet a stepping stone between R&D and an actual industrial application. Among others, a kinetic resolution could be applied to enhance the selectivity toward targeted products, for which exploiting available and inexpensive additives or co-electrolytes such as ionic liquids is a promising direction. Herein, we present an initial systematic analysis of the effect of various tetra alkyl ammonium salts on the CO2RR products distribution with the aim on ethylene, important industrial feedstock or building block. A selected ammonium salts of different alkyl chain length and number of charges provided very concise but sufficient chemical space to overview a structure-activity relationships, including changes in the reactions’ onset potentials and limiting currents. The overall experimentation progress was intensified by the employing a developed in our lab a gas diffusion electrode (GDE) cell, coupled to a mass spectrometer. This enabled to scan the selected library of salts during CO2RR under dynamic operations with detection of transients in real-time at relatively high current densities, between 10 to 400 mA/cm2, within further quantitative validation over standard long-term steady-state experiments. These results have broad implications for effectively stirring the CO2RR selectivity towards products containing either one or two carbon atoms.

Key words: CO2, Electroreduction, Copper, Electrocatalysis, Modifiers, Real-time, GDE
Cell Designs Optimizing the Cathode Outlet Purity of CO2 Electrolyzers
Authors: Kistler Tobias , Agbo Peter
Published: February 2024

Recently, advances in (photo-)electrochemical CO2 reduction have enabled record faradaic efficiencies for products containing at least two carbon atoms. However, comparatively little effort has been made to maximize the molar concentrations of the products that come out of the electrolyzer. In this presentation, I will talk about strategies and specific cell designs to optimize cathodic product concentrations, which may enable coupling the CO2 reduction cell to a downstream reactor that produces further reduced and more valuable products. Specifically, I will illustrate the concept with a system that enhances ethylene concentrations of an electrolyzer outlet stream.