bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Exoelectrogenicity of Genetically Engineered Hyperthermophiles
Authors: Suganthan Baviththira , Wu Chang-Hao , Haja Dominik K , Adams Michael W. W. , Ramasamy Ramaraja P.
Published: February 2020

A hyperthermophilic archaeon called Pyrococcus furiosus (Pf), is being explored as potential microbial catalyst for use microbial fuel cells (MFCs) [Sekar et al. (2017)]. The two main enzymes membrane bound hydrogenase (MBH) and cytoplasmic soluble hydrogenases (SH) are involved in its oxidative fermentative pathways. In P. furiosus the membrane bound hydrogenase (MBH) uses reducing equivalents from the oxidative fermentative pathway to produce hydrogen, which is believed to be used by soluble hydrogenases (SHI and SHII) for nicotinamide cofactor generation. However, in anaerobic respiratory systems, the oxidative fermentative pathways and the activity of MBH and SH enzyme complexes are not fully understood. In this study, we hypothesize that genetically manipulating the expressions of SH and MBH could influence extracellular electron transfer, which could be characterized by an enhancement in organism’s ability to reduce a metal ion (e.g. soluble ferric citrate or and insoluble ferric oxide). Herein, genetic traceable Pf strain was genetically engineered to produce strains with over-expressed SHI (OESHI), over-expressed MbhJ-N (OEMbhJ-N), knocked-out SHI/SHII (ΔSHI/II) or knocked-out MbhL (ΔMbhL). Soluble ferric citrate and insoluble ferric oxide were used to study the ability of engineered Pf strains to reduce the extracellular oxidants. Experiments revealed that the ΔMbhL strain, produced the highest exo-electrogenic ability among these Pf strains. To the best of our knowledge this is the first report that compares the exoelectrogenic ability of different strains of genetically engineered Pf.
Buckypaper Thickness Dependent Bilirubin Oxidase Electrochemistry
Authors: Krishnan Sadagopan , Walgama Charuksha
Published: February 2020

Among various electrode materials, freestanding buckypapers made from carbon nanotubes have gained significance as they do not require a solid support material and thus facilitate miniaturization. We present the effect of buckypaper (BP) thickness on the electrocatalytic properties of bilirubin oxidase (BOD) enzyme. In this study, we prepared BPs of varying thicknesses ranging from 87 micron, the minimum thickness for suitable handling with good stability in aqueous experiments, to 380 micron. BOD was adsorbed overnight onto the BPs. We determined that the lower range BP thickness (< 220 micron) exhibited better sigmoidal shaped electrocatalytic currents than the higher BP thickness based BOD biofilms with larger capacitive currents. Oxygen reduction current density of up to 3 mA cm–2 is achieved without use of any redox mediators or tedious electrode modifications. Using the 87 micron thick BP as the representative case, we were able to obtain distinguishable peaks for all Cu sites of BOD, and assigned their types, T1, T2, and T3, based on peak-width at half-maximum in anaerobic cyclic voltammograms. Our peak assignment is further supported by the appearance of dual electrocatalytic reduction waves at higher scan rate region (> 10 mV s-1) in oxygen-saturated buffer, which is identified to be driven by an ~ 3.5-times faster electron transfer rate from the buckypaper to the T2/T3 center than the T1 Cu site. Findings from this study are significant for designing new enzyme electrocatalytic systems and biosensors. In addition, accessing electrochemical and catalytic properties of often-buried inaccessible redox centers of many important metalloenzymes can be achieved by the freestanding BP design of optimal thickness.
Modified Microelectrodes for the Detection of Reactive Oxygen Species in Biomedical Studies
Authors: Kranz Christine , Daboss Sven , Hellmann Andreas
Published: February 2020

It has been long known that hydrogen peroxide (H2O2) as an endogenous reactive oxygen species (ROS) belongs to a group of destructive molecules that can lead to protein oxidation, lipid peroxidation, and DNA damage. Whereas elevated ROS production leads to oxidative stress, it was also recently shown that at lower physiological levels, H2O2 acts as an intracellular signalling molecule regulating kinase-driven pathways1. As the involvement and concentration levels of H2O2 at the cellular level are not fully understood, its localized detection at a cellular level is of particular importance. Fluorescent redox-sensitive dyes are frequently used for the detection of H2O2 at the cellular level. H2O2 can also be detected electrochemically, e.g. at anodic potentials (0.6 V vs. Ag/AgCl) at Platinum (Pt) electrodes. However, such high oxidation potential can be affected by co-oxidizable substances such as ascorbic acid, catecholamine etc., which may be present in biological samples2.

In this contribution, we present strategies of electrochemical H2O2 detection avoiding such interference problems based on electrocatalytically or enzyme-modified electrodes. Modification with Platinum black3 or Prussian Blue (PB)4 enables the detection at lower potential such as 0.3 V vs. Ag/AgCl at Pt-black modified electrodes and 0.0 V vs Ag/AgCl at PB modified electrodes, respectively. In particular, Prussian Blue (PB) modified electrodes show higher activity and significant higher electrochemical rate constants along with enhanced sensitivity. Hyperoxia treatment is controversial particularly in traumatic brain injury (TBI), due to increased radical and catecholamine production. To study increased release of ROS, measurements at porcine granulocytes and peripheral blood mononuclear cells will be presented using such modified microelectrodes. In addition, the co-detection of catecholamines such as epinephrine using dual sensors will be addressed. In order to study release at the single cell level, we recently introduced conductive colloidal AFM-SECM probes5, which serve as electrochemical transducers for the modification with Platinum black or Prussian Blue (PB) allowing the accurate provisioning of the biosensor at the cell surface.

References:

[1] D. R. Gough, T. G. Cotter, Cell Death and Disease 2, e213, (2011)

[2] Y. Zang, et al., Anal. Chem., 66, 1183-1188 (1994).

[3] S. Ben-Amor et al., Electrochim. Acta 126, 171–178 (2014)

[4] A. A. Karyakin, Electroanalysis, 13, 813−819 (2001)

[5] P. Knittel, H. Zhang, C. Kranz, G. G. Wallace and M. J. Higgins, Nanoscale,8, 4475–4481 (2016)
Advancing Battery Technology through Operando Neutron Scattering
Authors: Song Bohang
Published: February 2020

Operando characterization techniques including diffraction, microscopy, spectroscopy, etc. are emerging in the last few decades for the study of lithium-ion batteries (LIBs).[1] One of the many advantages of those techniques is that it can help to firmly understand the dynamic behaviors of battery components during the real operations, from various perspectives such as the physical/electrochemical/mechanical properties.

Among all operando characterization methods, diffraction using X-rays, electrons, and neutrons undoubtedly plays a vital role as it manages to answer the fundamental questions on the structural changes of any battery components, particularly the electrode materials. Compared to X-ray/electron, neutron diffraction (ND) has irreplaceable advantages for the study of LIBs. For example, neutrons are sensitive to light elements such as Li, C and O, which are often difficult to detect with X-ray/electron diffraction. Neutrons also offer drastically different scattering lengths for neighboring elements in the periodic table or isotopes for the same element. This feature enables the distinction between 3d transition-metal elements (Mn, Fe, Co and Ni) those are frequently used in cathode materials for LIBs. Unlike diffraction, neutron radiography (NR) has often been overlooked to study LIBs, despite it can provide full-scaled imaging information of a battery thanks to the excellent penetration depth of neutrons and good contrast between elements.

In this presentation, the speaker will introduce the most-recent developments made in Spallation Neutron Source (SNS)/High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory, dedicating to realize operando neutron scattering characterizations for the study of LIBs.[2] Operando ND and NR will be discussed individually based on the distinct scientific questions they could address.

[1] C. P. Grey; J. M. Tarascon, Sustainability and in situ monitoring in battery development, Nat. Mat., 2017, 16, 45–56.

[2] B. H. Song, et al. Metastable Li1+δMn2O4 (0 ≤ δ ≤ 1) Spinel Phases Revealed by in Operando Neutron Diffraction and First-Principles Calculations, Chem. Mater. 2019, 31, 124−134.
Investigation of Lithium-Silicon Alloy Phase Propagation Using High Resolution Operando X-Ray Microscopy
Authors: Choi Paul , Su Laisuo , Reeja-Jayan B. , Litster Shawn
Published: February 2020

Silicon (Si) is a highly attractive anode material for next generation lithium-ion (Li-ion) batteries due to its exceptional specific capacity (up to 4200 mAh g-1), natural abundance, and low environmental impact. However, practical implementation of anodes with high Si loading is hindered by the dramatic volumetric change Si undergoes during lithium insertion and extraction (~300%); such change in the electrode structure causes rapid capacity fade, poor cycle life, and electrolyte degradation from repeated solid-electrolyte interphase (SEI) formation. As such, a better understanding of the alloying behavior of Si in Li-ion systems is necessary to alleviate the problems caused by the lithiation and delithiation volume changes.

In this work, we utilize a combination of operando x-ray transmission microscopy and in-situ x-ray computed tomography at high resolutions to directly observe the lithium-silicon alloy phase nucleation and propagation. Three-dimensional reconstructions of Si electrodes at varying stages of cycling are used to resolve the spatiotemporal changes of the lithium-silicon alloy phases, and the changes in x-ray absorption are used to determine the predominant alloy phase within the electrode.

This material is based upon work supported by the National Science Foundation under Grant No. CBET-1705321. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
(Invited) Investigating Failure in Anode-Free Lithium-Metal Pouch Cells with Liquid Electrolytes
Authors: Weber Rochelle , Genovese Matthew , Louli Alexander J , Dahn Jeff R
Published: February 2020

Anode-free, or zero-excess lithium-metal cells, promise higher energy density than existing lithium-ion batteries. However, the abysmal performance of cells with lithium-metal electrodes prevents them from being used in commercial products that require long-life: electric cars and energy storage products. Many researchers believe all-solid state cells are necessary to achieve the lifetime required for these applications, but solid electrolytes complicate cell manufacturing and incur the huge costs required to rebuild existing production facilities designed to handle cells with liquid electrolytes. If a long-life anode-free cell could be made using a liquid electrolyte, this would be the best path forward for fast and inexpensive introduction into the existing market.

In this work, baseline NMC532/Cu anode-free pouch cells with 1M LiPF6 in FEC:DEC (1:2 vol) were tested at 40°C, with C/5 charge and C/2 discharge between 3.6 V – 4.5 V. Cells with this electrolyte lose 80% of their initial capacity before 20 charge-discharge cycles. Liquid electrolytes with different lithium salts are tested and show improved performance. To investigate the capacity loss mechanisms, SEM is used to track lithium morphology, XPS is used to compare SEI composition, and liquid NMR is used to track the electrolyte volume and degradation at various points throughout cycling. The results of these experiments are used to guide further optimization of the electrolyte composition which give incremental improvements in capacity retention. With continued works towards understanding the failure of these cells, a commercializable anode-free lithium-metal cell with liquid electrolyte may be realized.
Effect of the Direct Pre-Lithiation on Cycling Performance of Li Ion Battery with Silicon-Containing Anodes
Authors: Kim Kyoung Hwan , Shon Jeong-Kuk , Park Hwi-Yeol , Jeong Huisu , Lim Sungjin , Heo Jin S.
Published: February 2020

The desire to advanced lithium ion battery is growing with the expansion of electronic markets. Therefore, studies on making electrode materials with high energy density and long cycle life are actively conducted. Among those materials, silicon containing anode is one of the most important materials in making high energy density batteries because of the high theoretical capacity of silicon (~4200mAh/g). However, silicon containing anodes have the disadvantage of large initial irreversible capacity and continuous capacity loss due to large volume change of silicon. Because Li ions transferred from the cathode to the anode disappear without being reversibly used for charging and discharging, the capacity of the full cell becomes significantly smaller than expected. To solve this problem, pre-lithiation has been proposed as a powerful method which can be done through several methods including chemical and electrochemical pre-lithiation and pre-lithiation by direct-contact to lithium [1]. Pre-lithiation studies show that the Coulombic efficiency and discharge capacity dramatically increased.

In this research, we propose a method to improve a cycle life of Li ion batteries with silicon containing anodes by applying pre-lithiation to suppress the volume change of silicon. We applied a direct pre-lithation method to increase the cycle life through depositing Li onto the anode; which has an impact on the manufacturing process and the accurate controlling of Li amount. When the coin cell was fabricated with a high capacity cathode and a pre-lithiated silicon containing anode, we were able to obtain not only high discharge capacity (~18%) but also enhanced cycle life characteristics (~30%). In order to investigate the cause of improved cycle life of the cell, three electrode electrochemical experiments were conducted, and then the charged/discharged state of the anode and the cathode are separately extracted in the full cell profile. Analysis of the extracted profiles confirms that the end-voltage of the anode with accurate amount of extra Li is lowered, which means that the silicon in the anode did not completely shrink after discharge. This result demonstrates that the pre-lithiation method is effective in reducing the volume change of the silicon during cycling. Electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM) also supported the above results. We would like to share this result through the presentation and hope that this work will provide an effective method to build a long cycle life Li ion battery with silicon-containing anodes.

References

[1] Holtstiege, florian, et al, Batteries, 4.1 (2018): 4
Investigation of the Aging Behavior of Large Li-Ion Cells By a Novel Reassembling Process Using Coin Cells
Authors: Schmid Alexander Uwe , Birke Kai Peter
Published: February 2020

Cycle aging tests of high-capacity (Ah) Li-ion cells are cost and time intensive since (i) high currents have to be applied (expensive measurement set-up) and (ii) predicting the cell aging behavior requires many tests with different parameters, e.g. temperature, C-rate, depth of discharge. Analyzing the aging behavior of large Li-ion cells by means of cycling the extracted cell material in small coin cells would tremendously lead to a faster and effective aging prediction. Many aging tests could be parallelized since only very low currents are needed. The condition for comparability between coin- and original cells is the same aging mechanism in both cell types and a reproducible coin cell assembly.

We test our coin cell assembly method on 40 Ah Li-ion pouch cells. We extract 62 coin cells out of three pristine 40 Ah pouch cells. The coefficient of variation in capacity of those coin cells at begin of life is 1.42% which is in the range of cell-to-cell variations of industrially produced cells at begin of life. Calendar and cyclic aging tests of 40 Ah pouch cells and extracted coin cells are conducted at different temperatures. Differential analyzes and impedance measurements help to detect the aging mechanisms of both cell types.

Finally, factors are introduced which may explain the measured offset in the respective aging curves.
The Impact of Calendering on the Electronic Conductivity Heterogeneity of Lithium-Ion Electrode Films
Authors: Hunter Emilee E , Vogel John E. , Wheeler Dean , Mazzeo Brian A
Published: February 2020

Electrical conductivity is a key metric in the performance of lithium-ion batteries. However, accurately measuring the electronic conductivity nondestructively is difficult. We have developed a micro-four-line probe that has been used to make this measurement and to demonstrate the heterogeneity of electrical conductivity of lithium-ion electrodes on a mm scale [1]. Such heterogeneity or non-uniformity can cause the lithium ion battery to degrade unevenly overtime, which is undesirable.

The design of the micro-four-line probe has been improved into a flexible-four-line probe. This flexible measurement device is able to conform to the surface of the electrode, which improves the contact and the resulting electronic conductivity measurement. The flexible probe has been used to take accurate measurements of electronic conductivity and the contact resistance between the film and the current collector.

The microstructure of lithium-ion electrodes is another important characteristic that determines the performance of lithium-ion cells, including electronic and ionic conductivity of electrodes. Calendering, an important step in the manufacturing process, affects the microstructure as the film is compressed to a uniform thickness. Prior to calendering there are more substantial variations in the thickness of the electrode film, which constitutes surface roughness, as illustrated in the included thickness profile (figure).

The effect of calendering on the electronic heterogeneity of electrode films will be reported. The flexible probe will be used to measure the variation in electronic conductivity across the electrodes. A thickness analysis of the electrode films before and after calendering will complement the electrical measurements. This information increases our understanding of electrode manufacturing processes to allow for future optimization of these processes.

References:

Vogel et al., Electrochimica Acta 297, 820 (2019).

Figure 1
(Invited) Operando Analysis for Charge/Discharge Reaction Mechanism of Graphite Anode of Li Ion Battery
Authors: Fujimoto Hiroyuki , Kiuchi Hisao , Takagi Shigeharu , Shimoda Keiji , Okazaki Kenichi , Ogumi Zempachi , Abe Takeshi
Published: February 2020

The first preparation of Li-graphite intercalation compound (Li-GIC) was attempted by Hérold et al. in 1955. Since then, a lot of reports have been made mainly by the research groups in France, and with regard to the stage I and II compounds, it is clarified that they take the in-plane structures called by P(√3×√3)R30°. Though there have been many reports since 1970s, the detail discussion has not been done so far concerning the intercalation mechanism and in-plane structure of higher stage compounds. The first reason is that the concentration of Li species becomes smaller in the higher stages. The second reason is the strong preferred orientation of graphite. Such reasons make difficult to clarify the intercalation mechanism and in-plane structure. In order to improve the performance of Li-ion battery, it is essential to investigate the detail structure change of graphite electrode during the charge/discharge process. In this study, in order to elucidate the intercalation mechanism and structure change not only along c-axis, but also along the a,b-axes, we traced dynamically the intercalation reaction in Li-ion battery negative electrode by Operando measurement with synchrotron radiation diffraction.
(Invited) Acoustic Detection of Unwanted Lithium Deposition in Lithium Ion Batteries
Authors: Steingart Daniel , Hodson Thomas , Davies Greg , Bommier Clement , Denner Katherine
Published: February 2020

The ability to quickly charge lithium ion batteries at rates comparable to petrol refueling may be an accelerant for the adoption of EVs. In cells of sufficient energy density for EV applications rates faster than 3C can lead to the unwanted deposition of lithium metal on the anode, which at best puts the cell into an indeterminate state. In this work we explore the applicability of electrochemical acoustic signal interrogation for detecting and measuring the deposition of lithium metal within lithium ion cells. Initial experiments indicate sufficiently sensitive detection lithium plating such that BMS protocols may be developed to reverse early stage deposition.
Identifying the Role of Lithium Plating in Li-Ion Pouch Cells
Authors: Perumaram Rangarajan Sobana , Mukherjee Partha P. , Barsukov Yevgen
Published: February 2020

Lithium plating is a detrimental process that occurs in the negative electrode, leading to reduced cell performance and cycle life. The process of deposition of metallic lithium is limited to the anode and can be detected by monitoring the anode potential of the cell. In this work, a three-electrode pouch cell configuration is constructed which includes a reference electrode in order to enable in operando detection and quantification of lithium plating at different C-rates. It was observed that the cell exhibited three different regimes for capacity fade based on the dominant modes of degradation mechanisms at different cycle ranges, based on the relative amplitudes of the plating energy. The associated change in the high- and low-frequency resistance facilitated understanding the mechanisms contributing to the failure of the cell at different regimes.
Elucidating the Implications of Lithium Plating and Stripping in Li-Ion Cells
Authors: Kabra Venkatesh , Fear Conner , Mukherjee Partha P.
Published: February 2020

Today, Li-ion batteries are being utilized in a variety of energy-dense as well as power-dense applications. Under high rates of charge and/or low-temperature operations they often undergo deleterious reaction of Li metal deposition over graphite particles called Li plating. This leads to a significant drop in performance and lifetime of batteries. Due to a complex interplay of microstructural-electrochemical-thermal interactions, reliable non-destructive indicators of Li plating are still not well understood. Furthermore, the factors affecting the degree of reversibility of plated lithium and re-intercalation into the graphite electrode remain inconclusive. Herein an electrochemical-thermal model, incorporating Li plating and stripping reactions, is paired with experiments to study the underlying mechanisms that govern rest phase/discharge voltage profiles after a low temperature and/or high rate charge, and elucidating the reversible and irreversible Li plating. Factors such as graphite state of charge and Li plating morphology are found to influence rest phase behavior.
Synthesis and Characterization of Alumina-Doped Lithium Borovanadate Glasses As a Promising Cathode Material for Lithium Batteries
Authors: Kindle Michael , Kmiec Steven , d'Anciães Almeida Silva Igor , Martin Steve W , Eckert Hellmut , McCloy John S. , Song Min-Kyu
Published: February 2020

The desire for scalable energy storage technologies with higher specific energy densities has been intensified. Along with this, exploring and advancing new chemistries could provide alternatives to cobalt-based cathodes in sourcing and cost. Glass electrodes can have a capacity of 500 mAh/g and can be produced in facile melt quench procedures. In particular, many vanadate glasses have shown the improved performance compared to their crystalline counterparts. For examples, vanadate glass-based electrodes have exhibited increased capacity, better cycling stability and higher rate capability when compared to those of crystalline counterparts, V2O5 based cathodes. The improved performance in the glass system is primarily linked to the lack of irreversible loss that occurs from a crystalline phase changes which do not occur in amorphous materials. Many vanadate-modified glass systems have been investigated. However, a more detailed analysis of the effect of lithium borates and how they alter the glass system has not been carried out. Here we report our systematic studies on the effects of altering the content of lithium borate ratios on the modification of the boron coordination, and thus the formation of boron superstructures and non-bridging oxygen (NBO) sites.

While the LiBO2-V2O5 system is reported as a promising high-performance cathode material, this glass system shows inconsistent glass formability in literature at high vanadium content, which is the electroactive species. An analysis of the effect of LiBO2 and Al2O3 on the vanadate glass system has been performed. X-ray photoelectron spectroscopy (V) and nuclear magnetic resonance (B-11) data show that alumina stabilizes and increases the BO3 coordinated species and decreases V4+ concentration which promotes VO4 chains to form with BO3 units, which is a stable glass structure according to literature. This is likely due to the [AlO4]- species, which requires charge compensation and reduces the amount of [BO4]- units that need to form. The lithium being attracted to the alumina structures likely limits how much lithium can then depolymerize the borovanadate glass network. The boron coordination changes and NBO sites that can be seen can also be related back to the rate capability, stability and performance of these glasses in electrochemical cells. More NBO sites means better ionic conduction and thus better rate capability and utilization of the active material. This extension of the borovanadate glass forming region, confirmed by various structural analysis, could improve the energy density of lithium batteries as well as offer viable alternatives to cobalt-based cathodes. Glass electrodes are a very promising alternative to traditional intercalation chemistries and warrant more exploration.
Probing and Tuning Lattice Oxygen Redox in Li2RuxM(1-x)O3
for Design of High-Energy Li-Ion Batteries
Authors: Yu Yang , Karayaylali Pinar , Sokaras Dimosthenis , Giordano Livia , Gauthier Magali , Hong Wesley T , Kou Ronghui , Li Qinghao , Sun Chengjun , Yang Wanli , Charles Nenian , Maglia Filippo , Jung Roland , Shao-Horn Yang
Published: February 2020

The participation of anion redox in lithium transition metal oxides such as Li2RuO3 and Li2MnO3 for positive electrodes have opened a new avenue to boost up the energy density of current lithium-ion batteries. There are many schools of thoughts for the physical origin proposed to be responsible for anion redox and more direct and clear experimental evidence of anion redox is needed to further understand and utilize this phenomena. In the first part of this work, we demonstrated the electronic signature of oxygen-oxygen coupling, direct evidence central to lattice oxygen redox (O2-/(O2)n-) in charged Li2-xRuO3 after Ru oxidation (Ru4+/Ru5+) upon first-electron removal with lithium de-intercalation. Experimental and simulated Ru L3-edge X-ray absorption spectra (XAS) revealed that the increase in the high-energy shoulder intensity upon lithium de-intercalation resulted from increased O-O coupling, inducing (O-O) σ* with π overlap with Ru d-manifolds, in agreement with the similar changes in the O K-edge XAS spectra. Further support came from experimental and simulated O K-edge X-ray emission spectra (XES), where the broadening of the oxygen nonbonding feature upon charging also originated from creation of (O-O) σ* states. By combining differential electrochemistry mass spectrometry (DEMS) with core-level spectroscopies, we are able to quantify the percentage of this lattice oxygen redox across different Li2RuxM(1-x)O3
(M=Ti, Cr, Mn, Fe, Ir, Sn) chemistries, through which we proposed a preliminary electronic descriptor for reversible bulk oxygen redox activity. This study constructed a transferrable framework to rationally interpret the spectroscopic features by combining experiments and theory, and pinpointed the key spectra footprints related to lattice oxygen redox from a molecular level. We also proposed a simple descriptor to rationalize and facilitate novel positive electrode materials design for reversible anion redox activities in high-energy Li-ion batteries.
Quaternary Layered Li[Ni0.89Co0.05Mn0.05Al0.01]O2 (NCMA) Cathode for High-Energy Density Lithium-Ion Batteries
Authors: Kim Un-Hyuck , Nam Gyeong Won , Sun Yang-Kook
Published: February 2020

Li[Ni1-x-y
CoxAl
z
]O2 (NCA) and Li[Ni1-x-y
Co
x
Mn
y
]O2 (NCM) cathodes have been the archetypes of current high-energy density cathodes for Li-ion batteries. A hybrid of NCA and NCM cathodes, a quaternary system consisting of Li[Ni0.89Co0.05Mn0.05Al0.01]O2 (NCMA) was benchmarked against NCM and NCA with similar Ni contents. The quaternary NCMA cathode delivered a capacity of 228 mAh g-1 and outperformed the benchmarking cathodes in long-term cycling stability (85% after 1000 cycles). The reduction in the volume change during deintercalation and the enhanced intrinsic mechanical strength confirmed by the single particle compression test suppressed the microcrack nucleation and propagation. Microcrack suppression was important because microcracks serve as channels for electrolyte infiltration and lead to the subsequent surface degradation of internal surfaces. The proposed NCMA cathode provides extra cycling stability which is essential for electric vehicles, which require a long battery life and improvs the thermal stability of the cathode, which contributes to a safer battery.

Myung et al. ACS Energy Lett.
2017, 2, 196-223.

Kim et al. Energy Environ. Sci.
2018, 11, 1271-1279.

Yoon et al. Electrochem. Soc.
2015, 162, A2483-A2489.

Kim et al. ACS Energy Lett.
2017, 2, 1848-1854.
Unraveling the Role of Al Substitution in Anionic Oxygen Activity of Ni-Rich Layered Oxide Cathodes
Authors: Li Ning , Sallis Shawn , Papp Joseph K , McCloskey Bryan D. , Yang Wanli , Tong Wei
Published: February 2020

Ni-based layered oxides have attracted great attention for the development of high energy and high capacity Li-ion cathodes. The most popular Ni-based cathodes, LiNi
x
Mn
y
Co1-x-y
O2 (NMC) and LiNi
x
Co
y
Al1-x-y
O2 (NMC), are indeed derivatives of LiNiO2 by partially substituting Ni with Co, Mn or Al. The current trend to develop high-Ni and low-Co or Co-free layered Ni-based oxide cathodes, makes a strong push to the limit of Ni content in such layered oxides, leading to many common properties with their parent compound, LiNiO2. In fact, lithium nickel oxide often exists off-stoichiometry because of the presence of Ni2+ in the Li layer, which blocks the Li+ diffusion pathway upon lithiation/delithiation. Therefore, a second metal of a minimal content, such as Co or Al, which can somehow facilitate the formation of layered structure is still needed, although they are not strongly favored due to cost and sacrifice upon the use of inactive Al.

In this work, a number of Al substituted lithium nickel oxides, LiAl
x
Ni1-x
O2 (0 ≤ x ≤ 0.20), have been synthesized via a solid state reaction, showing good R
m layered structure. Along with their parent LiNiO2, the oxygen activity in these compounds have been studied using combined synchrotron X-ray absorption spectroscopy (XAS), resonant inelastic X-ray scattering (RIXS) and differential electrochemical mass spectrometry (DEMS). The goal of this research is to elucidate the role of Al on the anionic oxygen activity in Ni-based layered oxides, including both reversible anionic oxygen redox and irreversible oxygen release during the electrochemical process. The electronic structure of transition metal and O was investigated at different states of charge to obtain a complete picture of cationic and anionic redox during the charge/discharge process. Beyond the redox chemistry, the effect of Al substitution on the phase transformation at highly delithiated states, dominated by H2 to H3 phase transformation for LiNiO2, as well as thermal stability was carefully studied. We hope this work helps provide a comprehensive picture of the role of Al substitution on the overall performance of Ni-based layered oxide cathodes.
Understanding Surface Reactivity on Ni-Rich Layered Oxide Cathodes
Authors: Chen Guoying , Zhu Jian
Published: February 2020

The mass market penetration of electric vehicles demand lithium-ion batteries (LIBs) that deliver higher energy density, longer cycle life and better safety. [1] Layered lithium transition-metal oxides, particularly Ni-rich lithium nickel manganese cobalt oxides (LiNi
x
Mn
y
Co1-x-y
O2, x ≥ 0.5, referred to as NMC), are currently considered most promising cathode materials in meeting these requirements. The instability of NMC-based electrode surface, however, prevents them from stable high-voltage operation which is needed for achieving high energy density. [2,3] Insights into the mechanisms governing these instabilities are elusive due to the complex nature of these oxides.

Cathode materials are traditionally prepared by high-temperature ceramic methods which produce aggregated particles with significant inhomogeneity that can contribute to additional challenges in diagnostic studies and data interpretation. In our research, crystal samples with excellent uniformity and well-controlled physical properties are prepared. [4] For example, Figure 1 shows a series of NMC crystal samples with various morphologies. This provides a model platform to investigate the relationships among specific properties, surface chemistry and electrochemical performance without ambiguity. In this presentation, we show the specific role of chemical composition, elemental segregation, particle size and morphology on surface reactivity. Design strategies for better performing NMC cathode materials will also be discussed.

References

S.-T. Myung; F. Maglia; K.-J. Park; C. S. Yoon; P. Lamp; S.-J. Kim; Y.-K. Sun, ACS Energy Lett.
2017, 2, 196.

F. Schipper; E. M. Erickson; C. Erk; J.-Y. Shin; F. F. Chesneau; D. Aurbach, J. Electrochem. Soc.
2017, 164, A6220.

W. Li; B. Song; A. Manthiram, Chem. Soc. Rev.
2017, 46, 3006.

J. Zhu and G. Chen, J. Mater. Chem. A
2019,
7 (10), 5463.

Figure 1. SEM images of synthesized NMC crystal samples with four differet morphologies: a) octahedron, b) truncated-octahedron, c) polyhedron and d) platelet.

Figure 1
Cobalt-Based Lithiated Spinel Oxide As a Novel Zero-Strain Cathode
Authors: Lee Eungje , Han Jinhyup , Kwon Bob Jin , Dogan Fulya , Croy Jason R. , Thackeray Michael M.
Published: February 2020

Zero-strain electrode materials that exhibit extremely small volume changes during intercalation reactions provide unique opportunities for highly stable lithium batteries. In particular, intecalation-induced strain in electrodes is a major factor in the degradation of advanced lithium batteries. For example, recent studies of high-performance Ni-rich layered cathodes unequivocally show a clear correlation between particle fracture, due to anisotropic volume expansion of polycrystalline grains, and continuously increasing cathode impedance.[1] Such chemo-mechanical behavior of electrode materials is even more critical to all-solid-state batteries in which the solid-solid interface between the electrode and solid electrolyte is prone to cracking and disintegration, even with small volume mismatches during electrochemical cycling. The best known zero-strain electrode material is the Ti-based spinel, Li4Ti5O12, that has been developed as a stable anode. Recently, LiRh2O4 spinel has been reported as a zero-strain cathode that operates at 3.2 V vs. Li/Li+,[2] however, its practical use is limited by the high cost of the precious metal, rhodium. A more feasible zero-strain cathode candidate is the ‘low-temperature’ (LT) form of LiCoO2, which adopts a cubic, lithiated spinel structure, Li2[Co2]O4.[3,4] On lithium extraction, LT-LiCoO2 provides an attractive 3.6 V vs Li. However, despite the high operating voltage and minimal volume change, this zero-strain material has received little attention since its discovery because of its poor cycling stability. In this presentation we report that cation substitution greatly improves the electrochemical perperties of LT-LiCo1-xMxO2 electrodes (M = cations). The different effects of various cation substituents on electrode performance will be compared and the zero-strain intercalation mechanism in LT-LiCo1-xMxO2 will be discussed.

References

[1] D. Miller, C. Proff, D.P. Abraham, and J. Bareno, Adv. Energy Mater., 3, 1098 (2013).

[2] Y. Gu, K. Taniguchi, R. Tajima, S.-i. Nishimura, D. Hashizume, A. Yamada, and H. Takagi, J. Mater. Chem. A 1, 6550 (2013).

[3] R.J. Gummow, M.M. Thackeray, W.I.F. David, and S. Hull, Mater. Res. Bull., 27, 327 (1992).

[4] E. Lee, J. Blauwkamp, F.C. Castro, J. Wu, V.P. Dravid, P. Yan, C. Wang, S. Kim, C. Wolverton, R. Benedek, F. Dogan, J.S. Park, J.R. Croy, and M.M. Thackeray, ACS Appl. Mater. Inter., 8, 27720 (2016).
Electrochemical-Shock Resistant Single-Crystal Ni-Rich Layered Cathode Materials
Authors: Qian Guannan , Ma Zi-Feng , Li Lisen
Published: February 2020

Ni-rich layered oxides LiNi
x
M1
-x
O2 (x ≥ 0.6, M = combinations of Co, Mn and/or Al) are technologically important cathode materials for lithium-ion batteries due to their high energy density, good power capability, and lower material cost than LiCoO2. These materials are usually prepared by a co-precipitation and calcination method that produces micron-sized polycrystalline (PC) particles consisting of densely packed nanoscale grains. The unique microstructure and anisotropic Vegard coefficient of these materials make them vulnerable to grain boundary fracture (“electrochemical shock”), a major cause for battery impedance growth and performance degradation. We have recently developed a scalable method to prepare a variety of single-crystal (SC) Ni-rich cathode materials, such as LiNi0.6Mn0.2Co0.2O2 (NMC622), LiNi0.6Mn0.2Co0.2O2, and LiNi0.8Co0.15Al0.05O2. SC-NMC622 outperforms the commercially available PC-NMC622 in terms of cycling stability, rate performance, and thermal stability. Post-cycling structural characterizations reveal that the SC-NMC622 do not crack even when charged to 4.9 V vs Li+/Li and its surface undergoes less phase transformation than PC-NMC622 during cycling in a normal voltage range (4.3-2.8 V). Single-crystal Ni-rich cathode materials offer hope for fabricating mechanically reliable solid-state batteries and provide a unique platform for studying doping and surface modification methods to further improve the durability of Ni-rich cathode materials.
Analysis of Iron Oxide Powder Formation By Hydrothermal Method through a Statistical Experimental Design and Evaluation of Its Use As Anodes for Libs
Authors: Gülcan Feryat , Karahan Billur Deniz
Published: February 2020

It is known that size and shape are one of the important topics to be considered when to design electrodes for lithium ion batteries. Recently considerable attention has been paid to transitional metal oxide anodes, especially iron oxides due to their environmentally benign behavior and high theoretical capacities (>1000 mAh/g).

Therefore, in this work, 4 differently structured iron oxide nanoparticles have been synthesized via hydrothermal method, following the Taguchi experimental design. The effects of experimental parameters (precursor solution’s concentration, temperature and autoclave filling ratio) on the powder morphology have been examined by scanning electron microscopy analysis. Then, the structure of the powders have been characterized by X-ray diffraction method. And finally the electrochemical performances of these powders as anode material for lithium ion batteries have been done based on the galvanostatic test results (with 50mA/g rate, between 1mV-3V).

The results have shown that all samples performed higher initial discharge capacities than graphite. Whilst, all of them revealed low initial coulombic efficiencies, independent of their morphological and structural particularities. It is believed that although small size leads high contact area resulting improvement in the electrochemical performance of the electrode; the electronic conductivity of the sample should be improved to further ameliorate the electrode performance.
One-Step Preparation of Lif Coated Li to Stabilize Li Metal Anode
Authors: Cao Dianxue , Gong Zhe
Published: February 2020

Due to the extremely high energy density, lithium metal has become an important negative electrode material.However, the reaction of lithium metal with a liquid electrolyte results in the formation of a solid electrolyte membrane (SEI), which produces dendrites, resulting in a decrease of coulombic efficiency.Due to the lower solubility of LiF in the electrolyte and its high shear modulus, it is a candidate for SEI films to protect lithium metal anodes. However, creating a uniform layer of LiF film on the surface of lithium metal remains a huge challenge. Here, we used a simple method to synthesize a LiF film on the surface of the Li sheet. According to the principle that fluorinated graphite can react with Li to form a galvanic cell and produce a product LiF, we form a primary battery on the surface of metallic lithium to manufacture a LiF film.The modified lithium sheets were assembled into symmetrical batteries, and the batteries were subjected to constant current charge and discharge tests at different current densities. The results showed that they have better cycle performance. The LiF-modified lithium electrode was cycled for 400 cycles at a high current density of 3 mA cm-2. And in the cycle, the formation of lithium dendrites is reduced to stabilize the lithium metal anode. Therefore, this simple method brings great prospects for the safety of lithium metal batteries and the construction of high-energy lithium metal batteries.
New 2.1 V Lithium- Ion Battery with Sulfurized Polyacrylonitrile (SPAN) Anode and LiMn2O4 Cathode
Authors: Berhe Gebregziabehr Brhane , Su Wei-Nien , Hwang Bing-Joe
Published: February 2020

Sulfur/polyacrylonitrile (SPAN) composites are demonstrated as one of the interesting anode materials for lithium ion battery due to its high theoretical capacity, low cost and environmental friendliness. Herein, we investigated the electrochemical properties of SPAN composite as the anode material and LiMn2O4 (LMO) cathode for sulfur-lithium ion battery in carbonate based electrolyte for the first time. Sulfur as an anode coupled with a lithium-ion intercalation cathode creates a unique Li-ion/sulfur chemistry, realizing the highest energy density ever achieved, along with high safety and excellent cycle-life. The cell delivered a reversible discharge capacity of 1378.16 mAh/g at 0.1 C with specific capacity retention of 90.86% after 150 cycles. At 1 C, the capacity retention was 807.96 mAh/g after 400 cycles with an average decay rate of 0.7 mAh/cycle and average columbic efficiency of 99.5 % and its rate capability delivers a highly reversible capacity of 868.27 mAh/g at 2 C. The full SPAN/LMO cell is able to deliver a record high energy density of 185 Wh/kg (total electrode mass) and a power density of 270 W/kg (total electrode mass) at 1 C within the voltage ranging from 1 to 3.2 V. This new type of batteries surpasses current lead acid or VRLA batteries in gravimetric energy density four times. The capacity fading at 55 ℃ is mainly caused by the deposition of manganese on SPAN anode as XPS result confirmed. However, shuttling manganese was not observed when the cell was cycled at 25 o C. This strategy can be applied for other sulfur composite to provide a route for the development of high performance, cost effective and environmental benignity lithium ion based rechargeable batteries and the demonstrated cell with high rate and high capacity opens up new application opportunities for various electrical energy storage.

Keyword: - non-aqueous sulfur battery; SPAN composite; high capacity; energy storage
Characterization of Flowing Aqueous Solid Dispersions of Electroactive Lithium-Ion Battery Materials
Authors: Koenig Gary , Foley Sonia , Geng Linxiao , Gupta Devanshi
Published: February 2020

While there are many material characterization techniques that are employed for the quality control processes of lithium-ion battery active material powders, eventually the materials must be validated electrochemically in battery cells. This requires making the cells including slurry mixing, slurry coating and drying, electrode calendering and pairing, and final cell assembly. Fabricating cells requires significant equipment and material expense and, in some cases, significant time. Additionally, the cells must be electrochemically tested which depending on the protocol can take multiple days. A technique that provides insights into the electrochemical properties of battery materials without cell fabrication and electrochemical evaluation could improve battery active material powder quality control and potentially reduce the time and cost involved in material validation.

Our lab has been working on a technique where dispersions of battery active materials are evaluated electrochemically during collisions with current collectors. The technique has been referred to as dispersed particle resistance (DPR), and in previous studies we have shown that DPR measurements provide an indicator of the rate capability of lithium-ion battery active materials. DPR has a significant advantage with regards to timescale for material evaluation because the method takes only a few minutes and has the option of high throughput analysis due to a flow-through configuration. We have also adapted the technique to characterization of the particles in aqueous dispersions, and in this presentation we will demonstrate that the technique is effective with aqueous dispersions of cathode materials, including water-sensitive layered metal oxides with high nickel content such as LiNi0.8Mn0.1Co0.1O2.
Interest of Cross-Section Surface Analysis for Li-Ion Batteries and Beyond
Authors: Madec Lénaïc , Ledeuil Jean-Bernard , Gachot Grégory , Coquil Gaël , Courrèges Cécile , Monconduit Laure , Martinez Hervé
Published: February 2020

Conversion type reaction have revolutionized Li-ion batteries and beyond in term of performance as well as of fundamental aspects. To tackle the volume expansion issue occurring during lithiation/delithiation, composite materials made of electrochemically active/inactive elements have been successfully developed.1
,
2 However, direct evidence of the electrochemical conversion reaction as well as the role of the inactive elements over long term cycling still remains to be elucidated.

To tackle this issue, we propose advanced surface Auger / µXPS / ToF-SIMS imaging to analyze the chemical and morphological evolution of clean electrodes cross-sections, prepared by ion-milling. These innovative approaches were used to study ternary conversion materials, MSnSb (M=Ti or Nb) for which unexpected electrochemical performance were observed at high temperature.3
,
4 It provided a direct proof that the electrochemical conversion mechanism still occurred even after 400 cycles, which was unexpected. Importantly, it highlights the role of the inactive element (Ti or Nb) in the long term reversibility of the conversion reaction. Overall, a gradual shell to core expansion/break up of MSnSb particles is revealed during the continuous conversion reactions which leads to highly porous structures after 400 cycles. Finally, it will be showed that the developed approaches will benefit to the study of all-solid-state batteries for which buried interfaces have to be reached.

References

V. Aravindan, Y. S. Lee, and S. Madhavi, Adv. Energy Mater., 5, 1402225 (2015).

A. Mukhopadhyay and B. W. Sheldon, Prog. Mater. Sci., 63, 58 (2014).

L. Madec, G. Gachot, G. Coquil, H. Martinez, and L. Monconduit, J. Power Sources, 391, 51 (2018).

G. Coquil, M. T. Sougrati, S. Biscaglia, D. Aymé-Perrot, P. F. Girard, and L. Monconduit, Electrochim. Acta, 281, 619 (2018).