bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemically-Controlled Dimerization in Ferrocene-Containing Ureidopyrimidones: Effect of Ferrocene Position
Authors: Smith Diane , Mikhaylova Veronika , Cedano Mario
Published: December 2020

Ureidopyrimidones (UPy’s) are well-known to dimerize in weakly polar solvents via the formation of four strong, linear H-bonds. Application of heat or mechanical stress can be used to break these bonds, which has led to their use as a linker in self-healing supramolecular polymers. On-going research in our lab is focused on further increasing the versatility of the UPy system by creating electroactive UPy’s in which dimerization strength can also be controlled through oxidation and reduction. Previously, we have shown that dimers based on the ferrocene-UPy derivative, 1, break apart upon oxidation of the ferrocene to the ferrocenium form at mM concentrations in CH2Cl2. This could be due both to the creation of electrostatic repulsion and a decrease in H-bond strength due to the reduced H-donor ability of the O and N on the pyrimidone side. In this project, another Fc-UPy has been prepared, 2, in which the ferrocene is attached to the urea side of the molecule. In contrast to 1, oxidation of 2 shows a single reversible ferrocene CV wave in CH2Cl2 at mM concentrations. Under these conditions, 1H NMR indicates that 2 is fully dimerized, thus, it appears that, unlike with 1, oxidation has no significant effect on dimerization of 2. In both cases, oxidation would increase electrostatic repulsion. However, unlike in 1, oxidation of 2 should actually increase H-bond strength by making the urea NH a stronger H-donor. Therefore, it appears that the effect of oxidation on the H-donating or accepting ability is a more crucial factor for dimerization control than electrostatics in these systems.

Figure 1
Mechanistic Insight into the Catalytic Electroreduction of Tetrabromobisphenol-a at Carbon Cathodes
Authors: McKenzie Eric C.R. , Peters Dennis G
Published: December 2020

Polyhalogenated phenols are a class of environmental pollutants that serve as precursors to dioxins and behave as endocrine disruptors.1,2 As a result, an efficient route of degradation is needed. Traditional methods of remediation include microbial, thermal, and chemical pathways; however, these typically require large amounts of toxic solvents, excessive amounts of energy, and can be tremendously time-consuming.3 Electrochemistry has become a growing area of research for the remediation of environmentally-harmful compounds, as the electroreductive behavior of carbon–halogen bonds is well understood.

Herein, we report the electrochemical reduction of the flame retardant 3,3',5,5'-tetrabromobisphenol-A (TBBPA), at carbon cathodes in the absence and presence of nickel(II) salen. Cyclic voltammograms at varying scan rates, coupled with voltammograms in the presence of a hydrogen-bonding stabilizer, suggest reduction proceeds by cleavage of a carbon–bromine bond, followed by reduction of a short-lived intermediate. Controlled-potential (bulk) electrolysis was performed to determine the extent of reduction that could be achieved; moreover, gas chromatography–mass spectrometry was utilized to separate and identify reduction products. Electrolyses performed in the presence of deuterium oxide and 1,1,1,3,3,3-hexafluoroisopropanol-OD reveal a carbanion intermediate present in the reduction mechanism.

References

M. Montaño, A. C. Gutleb, and A. J. Murk, Environ. Sci. Technol., 2013, 47, 6071–6081.

C. D. Klaassen, Casarett & Doull’s Toxicology the Basic Science of Poisons, McGraw-Hill Education, 2013.

E. T. Martin, C. M. McGuire, M. S. Mubarak and D. G. Peters, Chem. Rev., 2016, 116, 15198–15234.
Continuous Flow Synthesis of N-Phenylphenylglycine By Dehydration and Electrochemical Carboxylation
Authors: Naito Yuki , Tanaka Kenta , Atobe Mahito
Published: December 2020

α-Amino acids and their derivatives are important and essential resources for human life such as foods, medical drugs, cosmetics and so on. The classical Strecker α-amino acids synthesis is a longstanding method although this classical method requires highly toxic cyanide reagents as the carbon source and these regents are unfavorable from the viewpoint of green chemistry. Carbon dioxide, on the other hand, would also be an abundant and favorable carbon source. There are several examples of synthesis of α-amino acids by direct carboxylation of imines with carbon dioxide. Because of chemical stability of carbon dioxide, this direct carboxylation requires stoichiometric quantities of hard to handle reagents such as magnesium metal and organotins under severe or harsh reaction conditions.

In this context, electrochemical carboxylation represents an attractive alternative to conventional chemical carboxylation methods because it is possible to readily generate highly reactive carbon nucleophiles that immediately react with carbon dioxide without handling sensitive, expensive, and toxic reagent. However, metal ions derived from sacrificial anode such as magnesium and aluminium anodes are generally required to stabilize the unstable carboxylate ions.

A flow microreactor enables fast generation and consumption of the unstable species. Therefore, it is attractive reaction system for electrochemical carboxylation involving unstable carboxylate ions without sacrificial anodes. Moreover, the electrochemical synthesis with a flow microreactor offers operational advantages over batch processes.

Under these backgrounds, we have demonstrated the electrochemical carboxylation of in situ generated imines in a continuous flow system. The present method enables an efficient synthesis for N-phenylphenylglycine derivatives using easily available aldehydes, amines, and CO2 without the use of toxic metal reagents and sacrificial anode.

As shown in Figure 1, the imine was smoothly generated from aldehyde and amine by dehydration using MS4A desiccant in a flow operation, and then reacted with carbon dioxide in the electrochemical flow microreactor to afford N-phenylphenylglycine derivatives with high to moderate yields.

Figure 1
(Invited) Closed Bipolar Electrochemistry for Sensor and Bioimaging Applications
Authors: Inoue Kumi Y. , Iwama Tomoki , Fakhruddin Siti Masturah , Shiku Hitoshi , Matsue Tomokazu
Published: December 2020

Closed bipolar electrochemistry (cBPE) involves simultaneous oxidation and reduction at the opposite poles of a conductor located in two separated solutions. This unique property is expected to be used as new electrochemical analytical tools including sensors and imaging platforms. I will introduce our researches for application of cBPE to sensors and bioimaging.

Our first application of cBPE is in a sensor device for liquid-junction-free substitutional stripping voltammetry (SSV) (Figure A) [1]. SSV is a method for highly sensitive amperometric measurement by integrating small oxidation current over time as a silver deposition. A general SSV uses a galvanic-like cell with a liquid junction to convert an oxidation current generated in one cell into silver deposition in the other cell. Then, the amount of silver deposition is quantified by stripping voltammetry. As an idea of eliminating the liquid junction prohibiting the miniaturization of the SSV device, we proposed a method using conductor alternative to liquid junction to obtain electrical continuity between two cells. I later realized that this configuration is the cBPE. We also applied cBPE to unique amperometric sensors including simultaneous multiple measurement device (Figure B) [2] and probe-type device integrating a reference electrode [3].

Our second application of cBPE is in an electrochemical imaging platform. In order to realize an electrochemical microscope for real-time bioimaging with single-cell level spacial resolution, we have employed closed bipolar electrode array with electrochemiluminescence (ECL) detecting system (Figure C). As a first demonstration, we successfully obtained an image of flowing [Fe(CN)6]3- ions on a cBPE array fabricated by bundling Au wires (200 µm in diameter) at a frame rate of 10 fps [4]. Then, a higher density cBPE array of which interval was 35 µm pitch on average was fabricated via electroless plating on a micropore membrane without any photolithographic technique. Using this cBPE array, difference in respiratory activity of a live and a dead MCF-7 spheroids was successfully imaged as oxygen distribution on the cBPE array.

Now we are on a research of operation of liquid junction free sensor using cBPE as well as researches for expanding the application of the cBPE based imaging platform. These studies are expected to further expand the possibilities of bipolar electrochemistry.

References:

[1] Shinichiro Takano et al., Electrochem. Commun., 66 (2016) 34-37.

[2] Kumi Y. Inoue, et al., ChemElectroChem, 5 (2018) 2167-2170.

[3] Siti Masturah binti Fakhruddin, et al., Electrochem. Commun., 93 (2018) 62-65.

[4] Tomoki Iwama, et al., Chem. Lett., 47 (2018) 843-845.

Figure 1
Electrochemiluminescence-Based Detection of Cell Surface Biomolecules By Using Cup-Shaped Microelectrodes
Authors: Kuriyama Airi , Kamata Tomoyuki , Kato Dai , Kojima Naoshi , Yamamura Shohei , Kim Hyonchol
Published: December 2020

Identification of biomolecules expressed on a cell surface is important, because their expressions usually imply condition of the cell, and fluorescence-based labeling and detection is one popular method for the identification of such molecules. In the method, specific antibodies are conjugated with fluorescent dyes, target molecules are reacted with the fluorescent antibodies, and expressions of the target molecules are identified with fluorescence observation. This method is target-specific and highly sensitive, however, detection sensitivity of the method is sometimes still insufficient. For example, one problem for the identification of circulating tumor cells (CTCs) is false-negative results caused on the missing of cancer cells on which target marker molecules are few expressed. Using of electrochemiluminescence (ECL)-based detection is one useful way to improve the sensitivity [1], however, ECL can be only irradiated from very close position of the electrode, and detection of cell surface molecules by ECL-based method is difficult because of large size of cells.

We propose a new method to detect cell surface biomolecules with ECL-based method by using cup-shaped microelectrodes. The hemispherical electrodes were composed of thin double layer [2], and in detail, the inner concave was low noise nano-carbon layer [3] and the outer was nickel. Diameter of the cup was almost the same as that of general animal cells [4], therefore, large area of the cell can be closely approached to the electrode surface with capture of the cell to inner concave of the cup. Epithelial cell adhesion molecule (EpCAM), which is a famous marker molecule for the identification of CTCs, was used for a model target in this study, and a human breast cancer cell line on which EpCAM was low expressed (MDA-MB-231) was used for the evaluation of EpCAM detection by ECL-based measurement. ECL probe (ruthenium(II) tris(bipyridine))-conjugated anti-EpCAM antibody was reacted with the cancer cells, the labeled cells were captured to inner concave of the cup-shaped microelectrodes, and ECL observation was performed. When electric voltage was applied, ECL was observed from cups in which cancer cells were captured. These results indicate that ECL-based detection of cell surface molecules can be achieved by using cup-shaped microelectrodes with quite high detection sensitivity.

References

[1] M. Liang et al., Assay Drug Dev. Technol., 5, 655 (2007)

[2] H. Kim et al., Jpn. J. Appl. Phys., 50, 06GJ03 (2011)

[3] O. Niwa et al., J. Am. Chem. Soc., 128, 7144 (2006)

[4] H. Kim et al., Sci. Rep., 4, 6362 (2014)
A Non-Invasive Cell Death Monitoring Based on an Automatic High-Throughput Cell Capacitance Measurements
Authors: Fanjul Pablo , Izquierdo-Bote Daniel , González-García María Begoña , Chacón Manuel , Suarez Lorena , Sánchez Manuel , Hernández-Santos David
Published: December 2020

In vitro cell death process monitoring is a method widely used in medical and pharmacological studies to know the effect of drugs and toxins on tissue models. This work presents a study of cell capacitance and its relation with cell death processes. With this objective, the state of the tissue models has been monitored based on the ability of the lipid membranes to accumulate electric charge after the passage of an alternating current of defined frequency, since the integrity of the lipid membranes of the cells has a direct impact on cell viability. For this purpose, capacitance in reconstructed human corneal epithelium tissue models has been evaluated after administration of increasing concentrations of an irritant compound, sodium dodecyl sulfate (SDS). After a period of topical exposure, cell viability was evaluated in terms of capacitance, and the results obtained were compared with a colorimetric assay widely used to evaluate cellular metabolic activity, the MTT assay.

A linear adjustment is observed in both methodologies, obtaining a linear regression for the viability values obtained by the MTT colorimetric test (R2 = 0.90) and for the capacitance values with respect to the SDS concentration (R2 = 0.99) at frequencies equal or greater than 3 kHz. Therefore, capacitance measurements have proven to be a good alternative for the study of cell viability, showing similar results to those obtained with the MTT assay, maintaining the integrity of the sample and being able to increase the number of studies performed on it. In addition, the monitoring of the evolution of cellular activity can be performed in an easy and faster way than the MTT assay, providing comparable results with the advantage of being able to continue using the measured sample.

This work was supported by the Project "NANOBIO-TEER" (IDE/2018/000485 and IDE/2018/000415), co-financed through IDEPA and ERDF fund.
(Invited) Electrochemical Evaluation of Bacterial Activity
Authors: Tanabe So , Sun Shuyi , Itagaki Satohiro , Urai Kazuki , Shiigi Hiroshi
Published: December 2020

A better understanding of the biological functions of microorganism is required to reduce their threats and increase their usefulness. Therefore, an importance of real-time evaluation of bacterial activity increase for various purposes such as hygiene management, development of antibacterial agents, and effective utilization of bacterial resources.1 This necessitates a quantitative assessment of metabolic processes, including growth and respiration. Here we would like to introduce the development of electrochemical methods for assessing bacterial activity.

Electrochemical detection of viable bacterial cells was performed using cell membrane permeable electron mediator and redox active pigment. Shewanella oneidensis MR-1 transfers electrons generated within the cell to the extracellular environment via the cytochrome complex in the inner/outer membranes and is one of the most useful bacteria for the recovery of metals, treatment of wastewater, and preparation of microbial fuel cells. By using potentiometric measurements, we have examined intracellular electron generation in bacterial suspensions of S. oneidensis supplemented with different carbon sources or ferricyanide, which was almost completely reduced to ferrocyanide during the incubation without affecting bacterial cell viability.2 On the other hand, a tetrazolium salt (MTT), which was converted to an insoluble reduction form (formazan) through the respiration of microbial cells.3 The insolubility of this formazan was effectively exploited as a surface-confined redox event. The electrochemical detection of formazan was effectively coupled with the thermal lysis of microbes. The sensitivity of the present technique is up to 10,000-fold higher than that of MTT colorimetry and requires an incubation time of only 1 h, which is approximately 1/4 of that required for other metabolism-based techniques. Furthermore, the measurement of the reduction current of dissolved oxygen provides an effective mean for assessing the respiratory activity of bacteria in suspension.4

1) T. Kinoshita, K. Ishiki, D. Q. Nguyen, H. Shiigi, T. Nagaoka, Anal. Chem., 90(6), 4098 (2018).

2) K. Ishiki, H. Shiigi, Anal. Chem., 91(22), 14401-14406 (2019).

3) K. Ishiki, D. Q. Nguyen, A. Morishita, H. Shiigi, T. Nagaoka, Anal. Chem., 90(18), 10903 (2018).

4) M. Saito, K. Ishiki, D. Q. Nguyen, H. Shiigi, Anal. Chem., 91(20), 12793-12798 (2019).
Evaluation on Hybrid-Electrolyte Structure Using the Liquid Electrolyte Interlayer Containing Lithium Borohydride at Li7La3Zr2O12 | Li Interface at High Operating Temperature
Authors: Takemoto Koshin , Wakasugi Jungo , Kubota Masaaki , Kanamura Kiyoshi , Abe Hidetoshi
Published: December 2020

Li metal battery with garnet-type Li7La3Zr2O12 (LLZ) as a solid electrolyte has attracted attentions as a promising candidate for high-energy batteries. However, the interfacial resistance between LLZ and Li is huge due to a point-point contact, leading to poor battery performances such as rate capability and cycleability. Here, we have studied the hybrid-electrolyte structure using the liquid electrolyte interlayer containing LiBH4 between LLZ and Li at high operating temperature of 120 °C. This hybrid-electrolyte structure offers high current density usage and a long-term cycleability. The Li|LLZ|Li symmetric cell shows high critical current density of 13 mA cm-2 and a long term cycle. The liquid electrolyte interlayer containing LiBH4 provides an improved coulombic efficiency of Li striping / plating due to an excellent reductive stability. Our findings suggest that the interfacial conditions on LLZ|Li could be effectively improved by using the modified liquid electrolyte interlayer.
Flexible 3D Cu/C Scaffolds As Lithium Host for Dendrite-Free Lithium Metal Battery
Authors: Chen Ke , Pathak Rajesh , Zhou Yue
Published: December 2020

Lithium (Li) metal has been considered as one of the most attractive anode materials in Li battery due to its high theoretical capacity (3860 mAh g-1) and low electrochemical potential (-3.04 V vs SHE). However, large volume change and fibrous or needle-like dendrites formation during battery operation hinders its commercialization. Here, a Cu/C foam Li host was designed for the first time based on pyrolysis of melamine-formaldehyde foam and followed by Cu deposition. The Cu/C foam with C as backbone and Cu as shell exhibits excellent flexibility and superior conductivity. The cross-linked flexible fiber network, as well as high surface area, enables a dendrite-free Li metal anode due to its self-adapted structure and reduced local current density. A high coulombic efficiency of 99.5% is achieved after 300 plating/stripping cycles (~1200 hours). Significantly, it can last for more than 170 cycles at a high current of 5 mA cm-2 for symmetric cell cycling test. Furthermore, the full cell with lithium iron phosphate (LFP) as cathode exhibits a long cycling life at a high current of 1C.
Polysaccharide-Based Self-Healing Polymer Binder Using Schiff Base Chemistry for High Performance Silicon Anodes in Lithium Ion Batteries
Authors: K K Rajeev , Kim Tae-Hyun
Published: December 2020

Lithium-ion batteries (LIBs) have become the most attractive energy storage system that enables a wide range of applications such as portable electronic devices and electric vehicles. The development of new generation of electrode materials with high energy density, long cycle life, and power capability has gained much attention nowadays. Silicon is considered as the most promising anode materials for LIBs due to its high theoretical capacity, low working potential, high abundance, and low cost. However, silicon suffers from serious volume changes during the lithiation/delithiation process, which gradually cause the pulverization of the electrode structure and finally fade the capacity. Polymeric binders with high mechanical properties can play a significant role in maintaining electrode structure from the volume expansion stress to achieve long term cycling capacity of the LIBs.

We herein introduce an in situ cross-linked self-healable natural polymer binder for Si anodes using oxidized alginate (OSA) as a cross-linker that contain aldehyde groups, which form covalent bonds with the amino groups of glycol chitosan (GCS) via Schiff base reaction in a reversible manner. The self-healing property and 3-D cross-linked structure of GCS-OSA binders provide multi-point interaction with the SiNPs surface, which provides stronger adhesion strength and higher mechanical robustness. Furthermore, the 3-D network structure and self-healing ability of GCS-OSA, which can accommodate the large volume change of silicon particles during the lithiation/delithiation process and hence maintain the electrode integrity of the anode. As a result, the silicon anode with GCS-OSA binder exhibits enhanced cycling performance and superior rate performance.
3-D Edge-Oriented Electrocatalytic NiCo2S4 nanoflakes on Vertical Graphene for Lithium Sulfur Batteries
Authors: Li Wenyue , Fan Zhaoyang
Published: December 2020

Polysulfide shuttling between the sulfur cathode and the lithium anode leads to low Columbic efficiency and cycling stability, which hinders the development of practical lithium sulfur batteries (LSBs). Introducing catalytic nanostructures to stabilize the otherwise soluble polysulfides and promote their conversion to solids has been proved to be an effective strategy in addressing this problem, but the heavy mass of catalysts often results in a low specific energy of the whole electrode.

In this work, nickel cobalt sulfide (NiCo2S4, NCS), one of the promising catalytic materials, was investigated to enhance the LSB performance by grafting it to vertical graphene (VG) grown on carbon nanofiber film(CNF) substrate. Different from previous studies, here NCS nanosheets possess ultrathin and edge-oriented structure, inherited from the underlying VG. As a result, this NCS/VG material not only significantly reduces the needed mass of NCS catalyst but also enormously improves the conductivity of the hybrid structure. When using this free-standing film as catalytic overlayer on top of the sulfur cathode, the polysulfide shuttle effect is largely alleviated, as revealed by the enhanced electrochemical performance and the catalytic function demonstration. The assembled LSB exhibited attractive electrochemical performances of 1000 mAh g-1 specific capacity at 0.3C and 800 mAh g-1 at 1C within 400 cycles for 2 mg cm-2of sulfur loading and 850 mAh g-1 specific capacity at 0.25C for 6 mg cm-2 of sulfur loading. An areal capacity of 4.5 mAh cm-2 was demonstrated at the 100th cycle at 0.3 C.
Local Interactions Governing the Performances of Lithium and Manganese-Richcathodes
Authors: Simonelli Laura
Published: December 2020

Li-rich layered transition metal oxides Li[Li0.2Ni0.16Mn0.56Co0.08]O2 are attractive electrode materials providing high energy densities, relatively good cycling stability with reduced environmental costs [1]. However, their utility in many applications suffers from both voltage and capacity fade, most likely related to structural transformations and not yet fully understood [2].

We investigated the manganese oxidation and spin states which are linked to the Mn size and magnetic interactions, resulting key parameters in defining the possible phases in which this cation may be involved [1, 3], and then in controlling the reversibility of the reactions along cycling. The Mn redox-state, constantly in opposition to the expected charge compensation, and spin-state resulted correlated with Ni oxidation/reduction, also spatially, suggesting that strain induced on the Mn−O sublattice by Ni oxidation triggers Mn reduction [3].

To elaborate design strategies that can be used to control the structure, for instance, hindering the spinel formation at the benefit of the electrode cycle life, it results then fundamental to address quantitatively how the strain controls the Mn oxidation and spin state.

Here we report about the local structural and electronical transformations during electrochemical cycling of a Li[Li0.2Ni0.16Mn0.56Co0.08]O2 cathode, combining several complementary techniques: X-ray absorption (Mn, Ni, and O K-edge) and X-ray emission spectroscopy (Mn Kβ emission line).

We focus mainly on the first charge and discharge cycle, identifying few key states of charge: the pristine state, the beginning and the end of the high voltage plateau, and the fully charged and following discharged states. The partially irreversible spinel formation, occurring at the expenses of the cycling layered phase, is quantified. Moreover, the local strains induced by the Ni oxidation have been characterized. Finally, the quantification of the different Mn electronic phases present at the different charge states along the first cycle permits to determine the charge redistribution among all elements of the cathode material.

The reported results unravel the role of strains in controlling the electrochemistry of Li-rich cathodes.

[1] Rozier, P.; Tarascon, J. M. Li-Rich Layered Oxide Cathodes for

Next-Generation Li-Ion Batteries: Chances and Challenges. J. Electrochem.

Soc. 2015, 162 (14), A2490.

[2] D. Mohanty et al. J. of Power Sources
229 (2013), 239

[3] L. Simonelli et al. J. Phys.
Chem.
Lett. 10, (2019), 3359

Corresponding author: lsimonelli@cells.es
Towards Stable Water-in-Salt Electrolytes for Sodium-Ion Batteries
Authors: Kuehnel Ruben-Simon , Reber David , Becker Maximilian , Battaglia Corsin
Published: December 2020

Water-in-salt electrolytes have enabled the development of novel high-voltage aqueous lithium-ion batteries due to their high electrochemical stability compared to traditional aqueous electrolytes.[1, 2] The development of equivalent sodium electrolytes is hindered by two factors:

Low solubility of suitable sodium salts. For example, NaTFSI has a solubility at room temperature of only 8 mol/kg compared to 21 mol/kg for LiTFSI.[3]

A higher salt concentration is needed to reach the same level of electrochemical stability due to the lower charge density of Na+ compared to Li+.[4]

In this study, we screen >100 combinations of up to five sodium salts with water to identify highly concentrated solutions that are thermodynamically in the liquid state at ≤25 °C.[5, 6] An additional criterion for a stable water-in-salt electrolyte is a high content of SEI-forming anions. Furthermore, we find that the electrochemical stability of the electrolyte benefits from anions that are only weakly coordinating. In fact, we discovered a strong correlation between the stability of the electrolyte and the position of the anion in the Hofmeister series.[6]

Our findings led to the development of multiple 2 V-class sodium-ion batteries with Coulombic efficiencies of up to 99.8% during cycling at a rate of 1C and record-high energy densities for such devices of up to 77 Wh/kg based on the active masses of both anode and cathode.[6]

[1] L. Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, C. Luo, C. Wang, K. Xu, Science 350 (2015) 938–943.

[2] Y. Yamada, K. Usui, K. Sodeyama, S. Ko, Y. Tateyama, A. Yamada, Nat. Energy 1 (2016) 16129.

[3] R.-S. Kühnel, D. Reber, C. Battaglia, ACS Energy Lett. 2 (2017) 2005–2006.

[4] D. Reber, R. Figi, R.-S. Kühnel, C. Battaglia, Electrochim. Acta 321 (2019) 134644.

[5] D. Reber, R.-S. Kühnel, C. Battaglia, ACS Mater. Lett. 1 (2019) 44–51.

[6] D. Reber, M. Becker, R.-S. Kühnel, C. Battaglia, submitted.
Ion-Conductive Self-Healing Polymer Network Based on Reversible Imine Bonding for Si Electrodes
Authors: Nam Jaebin , Kim Tae-Hyun
Published: December 2020

Lithium-ion battery (LIB), one of the most promising energy storage devices due to higher energy density than other secondary batteries, have continuously developed, and their market has been growing steadily. Currently, the efforts have been produced for using LIB in electric vehicles (EVs) and energy storage systems (ESS) storage beyond small portable devices. Higher energy density and faster charge/discharge rate are required for the practical application of LIB to these large-scale energy devices, and new materials to meet these requirements are hence necessary. Silicon has been reported as an anode material for the next-generation LIB due to its outstanding theoretical capacity and natural abundance. However, there are many limitations in practical application due to the continuous deterioration of the battery performances by enormous volume change of this active material. These problems are mainly originated from the structural deterioration of the electrode causing loss of conductive pathway and the active area for the electrode. Hence, many approaches to securing the structural stability of the Si electrode through various methods, including polymeric binders with good adhesion with Si were developed.

In this study, self-healable polymeric binder was designed through a crosslinking polymer network using a reversible imine chemistry. Additionally, the ion conductive polymer was introduced to improve ion conductivities of this self-healable binder. The synthesis, characterization and the electrical properties of the proposed polymeric binder for high-performance silicon electrodes will be discussed in detail.
Developing High-Voltage Electrolytes Via Anode-Free Cell Configuration
Authors: Hwang Bing-Joe
Published: December 2020

Currently, concentrated electrolyte solutions are attracting special attention because of their unique characteristics such as unusually improved oxidative stability on both the cathode and anode sides, the absence of free solvent, the presence of more anion content, and the improved availability of Li+ ions. The solvation structure of concentrated electrolytes is different from that of diluted electrolyte and the formation of ion-pairs takes place in concentrated electrolytes, which helps form a good solid-electrolyte-interphase. However, the ionic conductivity of concentrated electrolytes is normally lower compared to that diluted electrolytes. Most of the concentrated electrolytes reported are lithium bis(fluorosulfonyl)imide (LiFSI) salt with ether-based solvents because of the high solubility of salts in ether-based solvents. Here, an anode-free cell (Cu//LiNi1/3Mn1/3Co1/3O2) with all irreversible features is employed as a tool to develop non-flammable LiPF6-based high-voltage electrolyte. Two extreme electrolytes are chosen for comparison and understanding the fundamental science behind[1,2]. The best electrolyte developed also shows much better cycling performance in high-voltage lithium-metal batteries (HVLMBs) and high-voltage lithium-ion batteries (HVLIBs) compared to the commercial electrolyte, indicating the anode-free configuration is a powerful tool to develop electrolytes not only for HVLMBs but also for HVLIBs. Anode-free cell configuration can be scaled up as a tool to design electrolytes within short period of time and less cost in industrial level.

B Thirumalraj, TT Hagos, CJ Huang, MA Teshager, JH Cheng, WN Su*, and BJ Hwang*, “Nucleation and Growth Mechanism of Lithium Metal Electroplating,” Amer. Chem. Soc., 141, 18612-23 (2019)

TT Hagos, WN Su*, CJ Huang, B Thirumalraj, SF Chiu, LH Abrha, TM Hagos, HK Bezabh, GB Berhe, WA Tegegne, JY Cherng, YW Yang, BJ Hwang*, “Developing High-Voltage Carbonate-Ether Mixed Electrolyte via Anode-Free Cell Configuration”, Power Sources, 461, 228053 (2020).
Constructing a 4 Volt Aqueous Lithium Ion Battery Using Acrylate-Based Gel Electrolytes
Authors: Cresce Arthur v. , Eidson Nicolas Thierry , Schroeder Marshall , Ma Lin , Howarth Yakira J , Yang Chongyin , Ho Janet , Dillon Robert , Ding Michael S , Bassett Alexander , Stanzione Joseph , Tom Robinson , Soundappan Thiagarajan , Wang Chunsheng , Xu Kang
Published: December 2020

Highly concentrated solutions of lithium salts in water have made sweeping strides from the time in the early 2010s where aqueous electrolytes could operate a battery within an electrochemical window no more than 1.5V wide. In this presentation, we discuss the construction of a lithium ion battery using graphite as the anode and LiCoO2 as the cathode to make a cell with a 4.2V potential. The primary electrolyte is a water:trimethylphosphate hybrid with a water mole fraction of 0.44 and LiTFSI salt at a concentration of 9 molal. This aqueous hybrid electrolyte can be formed into a gel electrolyte by directly polymerizing acrylate-based monomers and crosslinkers dissolved in the electrolyte. We demonstrate that by protecting the graphite anode using an acrylate gel with a fluoroethylene carbonate-based liquid electrolyte, the battery cell can be cycled repeatedly between 3.0V and 4.2V just like a cell using organic carbonate electrolytes. The advantage of the aqueous hybrid electrolyte is that it is non-flammable, and a cell using aqueous gel electrolytes can withstand damage and even be cut open while operating with no risk of fire or explosion. The manufacturing and performance characteristics of the aqueous 4V battery will be discussed as well as the interfacial issues that come about with the use of aqueous gel electrolytes in a 4V-capable battery system.
(Invited) A Brief Understanding of Conduction Ions Transport Physics in Solid State Electrolytes
Authors: Shi Siqi
Published: December 2020

Solid state electrolytes refer to a type of solid materials whose conductivity is close to (or in some cases exceeds) the molten salt and electrolyte. It refers to a special state with liquid-solid duality where conduction ions have near-liquid mobility, while other ions maintain regular crystal arrangement. This liquid-solid duality is attracting the attention of Condensed Matter Physicists. Typical solid electrolyte materials, as a separate phase with novelty, generally have the following features: high ionic conductivity, low activation energy and open structure crystal. This open structure has a network of interconnected empty sites that the ions can occupy. In addition, fast ion conductors have important dynamic and collective effects: they do not have clear optical lattice modes, but there are diffuse low-energy excitations, frequency-dependent conductivity infrared peak, anomalous pre-NMR, phase transitions and a high probability of finding moving ions between two allowable positions. Considering basic research, the core problem of solid electrolytes is the transport of ions on the bulk phase, surface, and interface. This report will introduce the history of research on transport physics in several typical solid electrolyte systems, focusing on combining the work carried out by myself and partners to introduce the major progress in this area in recent years. At the same time, the role of computational physics/materials in the research of solid electrolyte materials is prospected.
Interfaces and Electrolyte Additives for Long-Life Sodium-Ion and Lithium-Ion Batteries
Authors: Chen Lin , Kishore Brij , Dancer Claire , Kendrick Emma
Published: December 2020

Sodium-ion batteries (NIBs) are attracting considerable attention as post lithium-ion batteries (LIBs) as they are a likely ‘drop-in’ technology which can be produced using existing manufacturing lines. One of the processes in manufacturing which is least understood is the formation and conditioning step; both battery technologies require a formation of the surface electrolyte interface (SEI) and cathode electrolyte interface (CEI) for long life cells. Here we discuss the formation, conditioning and electrolyte additives for the creation of the stable interfaces for high cycle life.

In particular we highlight the similarities of the formation step in the manufacturing process for a NIB layered oxide-hard carbon chemistry and LIB NMC-graphite, and the subsequent differences in the SEI observed1. Methods for faster formation protocols for NIB and LIB where targeted voltage windows in active formation methods produce more stable interfaces are introduced2,3 and we show the effect upon the composition of the SEI layer using these different protocols.

In all cases full cells were made with in a coin-cell figuration, these cells were subjected to different formation protocols and electrolytes additives such as FEC, VC and a new inorganic solid state additive. After formation the impedance of the cells were measured, and then cycled for 500 cycles at a higher rate to accelerate the ageing process. The resistance and the capacity of the cells were monitored during cycling. We show that even in a coin cell configuration significant differences in the cycle life are observed with different formation protocols and electrolyte additives. In addition we show the difference in the stability of the SEI in carbonate-based electrolytes between NIBs and LIBs. The effect upon the stability of the SEI and the performance of a NIB with a sodium metal oxide cathode and a hard carbon anode is discussed in detail and the role of the formation protocols and the inorganic additive. We also suggest the role of the additives for NIB and suggest the mechanism for which the stability is enhanced.

Roberts, S. & Kendrick, E. The re-emergence of sodium ion batteries: testing, processing, and manufacturability. Nanotechnol. Sci. Appl.
Volume 11, 23–33 (2018).

Pathan, T. S., Rashid, M., Walker, M., Widanage, W. D. & Kendrick, E. Active formation of Li-ion batteries and its effect on cycle life. J. Phys. Energy
1, 044003 (2019).

Kendrick, E. Optimisation Of Formation And Cell Ageing Protocols For Lithium Ion EV Batteries. Batter. Supercaps (2020). doi:10.1002/batt.202000048
Fast and Controllable Prelithiation of Hard Carbon Anodes for Lithium-Ion Batteries
Authors: Zhang Xiaoxiao , Qu Huainan , Ji Weixiao , Zheng Dong , Ding Tianyao , Abegglen Caleb , Qiu Dantong , Qu Deyang
Published: December 2020

As one of the potential alternatives to graphite, non-graphitizable hard carbon (HC) is of great interest for its high capacity and better rate performance. It is generally accepted that the higher capacity of HC comes from the random arrangement of single graphene layers, which provides extra voids to accommodate lithium.1 However, its practical application is hindered by a large irreversible capacity and thus low initial Coulombic efficiency (ICE) (<80%), which originates from the relatively large surface area, causing solid electrolyte interface (SEI) formation and side reaction between Li ions and surface functional groups. 2

Chemical prelithiation is one of the most effective method to compensate the Li loss and thus improve the ICE. It refers to the application of Li-containing reagents with strong reducing capabilities, which transfer the Li ions to the anode materials along with the redox reaction.3-4 The operation is rather simple and shows great potential for industrial application with a suitable roll-to-roll design. In this study, the chemical prelithiation reagent, Li-biphenyl-tetrahydrofuran, was evaluated for its prelithiation capability in hard carbon electrodes through the immersion method. The prelithiation extent can be easily controlled by tuning the reaction time. A short time of 30 s results in a high ICE of ~106% in half cell. The improvement of ICE was evaluated in full cells as well. When matched with a LiNi1/3Co1/3Mn1/3O2 cathode, the full cell with the prelithiated hard carbon anode exhibits a much improved ICE and cycling performance than those of the pristine full cell. SEM, XPS, and EIS analysis were conducted to investigate the SEI difference between pristine and prelithiated samples, and the prelithiation mechanism was proposed.

References

(1) Nagao, M.; Pitteloud, C.; Kamiyama, T.; Otomo, T.; Itoh, K.; Fukunaga, T.; Tatsumi, K.; Kanno, R. Structure Characterization and Lithiation Mechanism of Nongraphitized Carbon for Lithium Secondary Batteries. J. Electrochem. Soc.
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(2) Xing, W.; Dahn, J. R. Study of Irreversible Capacities for Li Insertion in Hard and Graphitic Carbons. Journal of The Electrochemical Society
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(3) Scott, M. G.; Whitehead, A. H.; Owen, J. R. Chemical Formation of a Solid Electrolyte Interface on the Carbon Electrode of a Li‐Ion Cell. J. Electrochem. Soc.
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(4) Tabuchi, T.; Yasuda, H.; Yamachi, M. Li-doping process for LixSiO-negative active material synthesized by chemical method for lithium-ion cells. J. Power Sources
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(Invited) The Role of Electrolyte Solution in Next-Generation Batteries
Authors: Johnson Lee R
Published: December 2020

Lithium-ion electrolytes are predominantly base on carbonate solvents and have been instrumental in the success of the lithium-ion battery.1 Uniquely, their ability to form a stable solid-electrolyte interphase (SEI) at lithiated carbon electrodes underpins the battery.2 Unfortunately, the lithium-ion battery is approaching maturity and attention is turning to alterative next-generation batteries that are able to deliver enhancements in energy, power, sustainability and cost. Often, the challenges in next-generation batteries are very different from those found in the lithium-ion battery.3 New understanding and advancements in electrolyte chemistry will be needed to realize these technologies.

Here, we look at how electrolyte chemistry and impurities can control charge/discharge reactions in next-generation batteries. For example, the lithium-air battery has one of the highest specific energies of any known secondary battery chemistry, but faces significant challenges.4 The battery operates via oxidation of lithium metal at the anode, coupled to reduction of oxygen and formation of lithium peroxide at the cathode and these reactions are heavily influenced by the electrolyte chemistry.5 Moreover, to operate in air they must tolerate H2O, and here we describe how solvent chemistry is able to control the discharge route from a 2-electron reaction to an irreversible 4-electron reaction. This theory explains why cells are able to tolerate 1 M H2O,6,
7 and we show that with judicious selection of the electrolyte, up to 4 M H2O can be tolerated at the positive electrode of the battery. The impact of electrolyte chemistry on anode reactions will also be discussed. Recently, there has been significant research into magnesium anodes due to their high volumetric capacity (twice that of metallic lithium) and limited dendrite formation.8 Here we consider the nature of SEI films at magnesium in simple salt glyme ether electrolytes and how this impacts the cyclability of magnesium metal. Our results demonstrate the formation of a dynamic SEI at magnesium.

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R. Attias, M. Salama, B. Hirsch, Y. Goffer, and D. Aurbach, Joule, 3, 27–52 (2019)
(Battery Division Student Research Award Address Sponsored by Mercedes-Benz Research & Development) Investigating Anomalous Conductivity in Low Permittivity Electrolytes for Multivalent Battery Applications
Authors: Self Julian , Hahn Nathan T , Fong Kara D. , McClary Scott A , Zavadil Kevin R , Persson Kristin A.
Published: December 2020

Many of the liquid electrolyte candidates for multivalent batteries exhibit increasing molar conductivity with concentration. In other words, the concentration-normalized conductivity increases as a function of salt concentration. This is in contrast to conventional electrolytes, e.g. aqueous or cyclic carbonate-based electrolyte solutions, where the molar conductivity decreases with concentration due to increased viscosity and ion aggregation. Low permittivity electrolytes with increasing molar conductivity include Ca(BH4)2 in tetrahydrofuran, Mg(TFSI)2 in monoglyme and Mg(TFSI)2 in diglyme.

In order to investigate the origin of this anomalous molar conductivity trend, we study the physicochemical properties of the electrolytes using a combined computational/experimental approach. Ab initio calculations and classical molecular dynamics simulations are undertaken to study ion speciation, ion activity and changes to solution permittivity. Furthermore, we undertake conductivity, microwave and Raman spectroscopy measurements.
Solution NMR Studies of Electrolyte Decomposition Pathways
Authors: Rinkel Bernardine L. D. , Hall David S. , Temprano Israel , Grey Clare P.
Published: December 2020

One approach to increasing the energy density of lithium-ion batteries is to increase the operational upper voltage limit. However, higher cell voltages tend to lead to rapid capacity fade and shorter cycle life. This is typically ascribed to the loss of oxygen due to surface reconstructions of the cathode material, increased electrolyte oxidation rates, and transition metal dissolution.

It is well-known that electrolyte decomposition can negatively impact cell behaviour and lifetime by causing gassing, electrochemical impedance growth, or slippage, and that extensive electrolyte oxidation at high cell voltages can induce eventual rapid capacity loss or ‘rollover’ failure.1,2 Whereas the reduction processes at the anode have been well-studied and are generally understood,3 the chemical pathways and mechanisms for oxidation at the cathode remain relatively unknown. It is desirable to develop a more detailed chemical understanding of electrolyte degradation in support of longer-lasting high voltage materials and cell designs.

Herein, operando pressure measurements, liquid-state NMR, and electrochemical methods are combined to study electrolyte oxidation at multiple cell voltages. LiCoO2 (LCO)/Li cells were cycled with a lithium-ion conducting ceramic separator to identify the degradation products formed at the anode and cathode separately and to prevent further reactions of these species on the opposite electrode. The results are compared with the species generated by electrochemical oxidation of the electrolyte in a simple H-cell and with cells cycled without a separator. A major finding of the present work is that all degradation products from the cathode side of the LCO/Li cells can be explained by chemical oxidation of the electrolyte, involving oxygen evolved from the cathode surface, at least up to 4.9 V vs. Li/Li+. This result is consistent with and complementary to previously reported online electrochemical mass spectrometry results4 and has significance for nickel-containing cathode materials (e.g., NMC). Finally, a comprehensive summary of electrolyte degradation pathways was constructed by analysing a series of multinuclear and one- and two-dimensional NMR spectra.

Reference
s
:

[1] L.M Thompson, W. Stone, A. Eldesoky, N.K. Smith, C.R. M. Mcfarlane, J. S. Kim, M. B. Johnson, R. Petibon and J. R Dahn, J. Electrochem. Soc., 165 (2018), 2732-2740.

[2] X. Ma, J. E. Harlow, J. Li, L. Ma, D. S. Hall, M. Genovese, M. Cormier, J. R. Dahn, S. Buteau, J. Electrochem. Soc., 166 (2019), A711-A724.

[3] S. K. Heiskanen, J. Kim, B. L. Lucht, Joule, 3 (2019), 2322-2333.

[4] R. Jung, M. Metzger, F. Maglia, C. Stinner, H. A. Gasteiger, J. Phys. Chem. Lett., 8 (2017), 4820-4825.