bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectral Imaging Technologies for Food Safety and Quality Evaluations
Authors: Kim Moon Sung
Published: February 2020

ARS researchers in Beltsville, Maryland, pioneered the online implementation of hyperspectral/multispectral line-scan imaging technologies in a commercial food processing environment such as wholesomeness inspection of broiler chickens on poultry processing lines. The research and development effort for the use of hyperspectral line-scan imaging as a multispectral platform has been expanded to online produce safety and quality inspection. To achieve comprehensive online quality and safety inspection of fruits and vegetables, whole-surface sample presentation and imaging regimes must be considered. Because of the morphological shape differences between relatively round fruits and flat leafy greens, two independent methods are in development to achieve effective whole-surface sample evaluation based on the use of a single hyperspectral line-scan imaging device on a processing line. The whole-surface fruit and vegetable spectral imaging methods that allow simultaneous safety and quality inspection online are presented.
New Development in Physical, Chemical, and Biological Sensors for Precision Agriculture
Authors: Cheng Z.-Y.
Published: February 2020

Agriculture and forest are not only the primary source for food, but also a primary source for energy and engineering materials. Unfortunately, agriculture is also a great consumer of natural resources, such as water. As the population creases and living stand is continuously improved, the consumption of food and the need for energy continuously increases. At the same time, the available land for agriculture decreases. All these require the agricultural practice to be more efficient and productive. That is, the resources used in the agriculture practice should be minimized when the productivity is maximized. To reach goal, various sensors including physical, chemical, and biological sensors are required to monitor the living condition and the presence of hazard materials, pathogens, or insects. In this talk, honeybee is used for a case of study to illustrate the importance of these sensors for future agriculture.
Phase-Based Electrochemical Biosensors for Detection of Pathogenic Bacteria
Authors: Zhou Yan , Ramasamy Ramaraja P.
Published: February 2020

Bacterial pathogens are universally present in the environment and easily contaminate food and water to cause serious food-borne illness to humans. Detecting these pathogens in ultra low quantities is critical to prevent major outbreaks of food-borne diseases. Several approaches have been explored for detecting pathogenic bacteria in food and water of which electrochemical biosensors offer unique advantages including rapid detection, high sensitivity and easy-to-use testing procedure. However the specificity of detection and the cost of the biosensor heavily depend on the type and nature of the bio-recognition element used. Enzymes and antibodies are highly susceptible to environment and have low stability when used on electrodes. In this work, bacteriophage (virus) has been explored as an alternative bio-recognition element for the detection of pathogenic bacteria.  More specifically, a wild type T2 phage was utilized as recognition element for direct detection of Escherichia coli, ATCC 11303. The T2 phage was immobilized on carbon nanotube modified screen-printed carbon electrodes (SPE) using a molecular tethering approach developed by us.1 The binding of phage to the carbon nanotubes was verified by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The phage-modified electrodes were used to specifically detect E. coli. Electrochemical impedance spectroscopy was used to detect the impedance variations resulting from the binding of E. coli to T2 phage. The phage-based biosensor showed high sensitivity towards the detection of E. coli and the controls in the absence of phage did not show any signal for the E. coli detection.

References:

Ramasamy, R. P.; Luckarift, H. R.; ivnitski, D. M.; Atanassov, P. B.; Johnson, G. R., High electrocatalytic activity of tethered multicopper oxidase-carbon nanotube conjugates. Chemical Communications
2010, 46 (33), 5977-6188. 

Figure 1
A Biosensor Based on Magnetic Resonance Relaxation
Authors: Sullivan MariAnne , Prorok Bart Charles
Published: February 2020

This work describes a biosensor based on magnetic resonance relaxation switching. The method leverages a large body of work involving nanoscale contrast agents employed in nuclear magnetic resonance (NMR) imaging. The aim was to develop a detection approach that mimics the human immune response to an invading pathogen, the release of 109 to 1012 specific antigens to guarantee quick contact with the pathogen. The technique employs magnetic nanoparticle contrast agents conjugated with specific capture agents to achieve a similar contact goal. Detection of the species involves monitoring the average relaxation time (T2) of water protons in the solution, which is highly sensitive to the concentration and distribution of the magnetic nanoparticles present. With multiple nanoparticles attaching to each individual target species their distribution will be altered, and correspondingly, the average proton relaxation time will change
Detection of Multiple Pathogens on Fresh Produce Using a Surface-Scanning Coil
Authors: Wang Fengen , Horikawa Shin , Chai Yating , Hu Jiajia , Du Songtao , Liu Yuzhe , Wikle Howard Clyde , Chin Bryan A.
Published: February 2020

The wireless phage-based magnetoelastic (ME) biosensor combined with a surface-scanning coil is being developed as a direct pathogen detection method on food surfaces. The biosensor consists of a free-standing ME resonator as the signal transducer that is coated with a genetically engineered phage as the biomolecular-recognition element. Due to the Joule magnetostriction effect, the biosensor can be placed into mechanical resonance when subjected to a time-varying magnetic field alternating at the right frequency. The detection is based on measuring a change in the sensor’s resonant frequency, which is proportional to the number of pathogens bound to the biosensor. This paper investigates the real-time detection of multiple bacterial pathogens, Salmonella Typhimurium and Bacillus anthracis Sterne spores, on apple surfaces using ME biosensors. Measurement biosensors coated respectively with E2 phage (specific for S. Typhimurium) and JRB7 phage (specific for B. anthracis Sterne spores) were prepared and used for detection. Control biosensors (without phage) were also fabricated and used to compensate the effects of environmental changes. Fresh apple surfaces were spiked with S. Typhimurium cells, B. anthracis spores  and their mixtures with known concentrations. Both measurement and control sensors were placed directly on the apple surfaces, and these pathogens were detected simultaneously by wirelessly monitoring changes in the biosensors’ resonant frequency in real time in a humid environment. These frequency shifts were measured with a surface-scanning coil detector. The pathogen binding was then confirmed by optical and scanning electron microscopy. The results showed that specific binding of the pathogens on the measurement sensors has occurred. The effects of masking bacteria such as Escherichia coli on the detection performance were also investigated.
A New Nasicon-Structure Phosphor As a Blue Component for White LED
Authors: Kim Yoon Hwa , Im Won Bin
Published: February 2020

White light-emitting diodes (WLEDs) continue to gain scientific and commercial important in the present age of solid-state lighting. High power WLED components are required strong thermal stability because its generate heat during LED operation. Thus, the eventual performance of the WLEDs based on phosphors strongly depends on the luminescence properties of the phosphors. Therefore, it is highly desirable to find new phosphors with high efficiency and thermal stability.

In this study, we report a new blue-emitting phosphor, the Eu2+-doped NASICON, which can be used to forbid thermal quenching of optical characteristic for WLEDs. The influence of isomorphic displacements on phase transition temperature and the change of photoluminescence intensity have been explored, and established their correlation. By fabricating of WLEDs, we explored for its potential suitability in WLED applications. This suggests that the phosphor displays great potential application as near-ultraviolet LEDs for white light generation, with high quality.

Figure 1
Single Particle Measurement Technique Using Tweezers-Type Probe for Insertion Materials
Authors: Yamada Yuto , Ohmura Tomohiro , Munakata Hirokazu , Kanamura Kiyoshi
Published: February 2020

To evaluate the electrochemical properties of active materials of lithium-ion batteries, those composite electrodes including binder and conductive carbon are generally prepared and tested as coin-type and pouch-type cells. However, the use of composite electrode sometimes makes it difficult to investigate the intrinsic electrochemical properties of active material because the electrochemical response of composite electrode is strongly influenced by its porosity, thickness and composition. In order to eliminate such secondary factors from the electrochemical evaluation of active material, we have focused on single particle measurement, in which a single particle of active material can be measured [1]. So far, we have used a needle-type probe (current corrector) to measure the electrochemical properties of various single particles such as LiFePO4
[2] and graphite [3]. However, the needle-type probe is sometimes difficult to apply to the active materials with large volume changes during charge and discharge. In order to solve this problem, we have developed a tweezers-type probe (Fig. 1). In this study, this tweezers-type probe was applied to evaluate the intrinsic electrochemical properties of Si-based anode materials with large volume changes.

In single particle measurement, an optical microscope was set in a globe box filled with dry Ar gas, and a measurement cell was set on this stage. A single particle of target active material was pinched with a tweezers-type probe under microscope observation, and then its electrochemical measurement was carried out. A mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (1:1 in volume) containing 1 mol dm-3 LiPF6 was used as an electrolyte solution.

Fig. 2 shows charge-discharge curves of a Si particle measured by using a tweezers-type probe. Typical charge and discharge curves of Si with potential plateaus at around 0.2 V and 0.4 V were observed [4]. When using a needle probe, it was difficult to maintain the contact with Si particle, resulting in poor reproducibility. In contrast, even repeating cycles, the contact between the tweezers-type probe and Si particle could be maintained by using the tweezers-type probe. This result clearly shows the advantage of tweezers-type probe on evaluation of intrinsic electrochemical properties of advanced active materials with large volume changes.

Reference

[1] Kaoru Dokko, Natsuko Nakata, Kiyoshi Kanamura, Journal of Power Sources 189 (2009) 783-785.

[2] Hirokazu Munakata, Bunpei Takemura, Takamitsu Saito, Kiyoshi Kanamura,
Journal of Power Sources 217 (2012) 444 – 448.

[3] Kaoru Dokko, Natsuko Nakata, Yushi Suzuki, Kiyoshi Kanamura, J. Phys. Chem. C 114 (2010) 8646-8650.

[4] S. D. Beattie, D. Larcher, M. Morcrette, B. Simon and J.-M. Tarascon, J. Electrochem. Soc. 115 (2008) A158-A163.

Figure 1
Improvement of Electrode/ Electrolyte Interfaces in Graphite/LiNi0.5Mn1.5O4 Batteries at High Voltage with Lithium Trimethyl Alkyl Borates As Electrolyte Additives
Authors: Lucht Brett L , Xu Mengqing , Zhou Liu , Dong Yingnan , Totempudi Usha , Garsuch Arnd , Chesneau Frederick Francois
Published: February 2020

Lithium trimethyl alkyl and aryl borates (LTMB) has been prepared and investigated as a novel cathode film forming additive to improve the performance of LiNi0.5Mn1.5O4 cathodes cycled to high potential (4.8 V).  Addition of LTMB to 1.2 M LiPF6 in EC/EMC (3/7) improves the capacity retention of graphite/LiNi0.5Mn1.5O4 cells cycled at 55 oC.  The added LTMB is sacrificially oxidized on the surface of the cathode during the first charging cycle.  The LTMBs can be used as a functional group delivery agent via reaction of trimethyl borate with of the appropriate lithium alkoxide.  Over 40 different LTMBs have been prepared and investigated.  Ex-situ surface analysis of the LiNi0.5Mn1.5O4 by Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), Transmission Electron Microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) reveals inhibition of electrolyte oxidation on the cathode surface and the presence of a borate based passivating layer.  The novel cathode electrolyte interface (CEI) leads to the performance improvements.
(Invited) Study of SEI on High Performance 3D SiNWs and Sinps Based Anode for Lithium Ion Batteries
Authors: Peled Emanuel , Patolski Fernando , Golodnitsky Diana , Freedman Kathrin , Davidi Guy , Schneier Dan , Goor Meital , Goldstein Keren
Published: February 2020

In order to increase the energy density of the lithium battery, better anodes and cathodes are still required. Silicon has attracted much attention because its theoretical capacity is 4200mAhg−1, an order of magnitude greater than that of graphite. Nevertheless, the main disadvantage of high-capacity anode materials is their very large volume expansion and contraction (~320% ) during Li insertion/de-insertion, followed by cracking and pulverization of the anode material. Si nanostructures have the advantage of a shorter diffusion distance for lithium species, which can improve the power performance of the battery. Studying of large surface capacity anodes (high Si loading) is almost nonexistent. Several degradation mechanisms are involved in the charge-discharge process of SiNWs-based anodes, including: 1) SEI thickness and resistance increase, 2) solvent and salt reduction which leads to drying out of the electrolyte and to precipitation of a "secondary" porous SEI, 3) large increase in battery impedance and reduced power, 4) breaking or disintegration of the SiNWs, 5) loss of SiNW contact to the current collector and 6) cracks in the electrode due to large volume expansion of the SiNWs. In this work, in addition to the synthesis and characterization of novel three-dimensional high-capacity SiNWs and SiNPs-based anodes, we focused on studying their degradation mechanisms.  We have been able to produce remarkably high loadings of 3-15 mAh/cm2, very low irreversible capacity (of the order of only 10% for the 3-4 mAh/cm2 samples), current efficiency greater than 99.5% and a fast charge–discharge rate (up to 2.7C (20mA/cm2) which is not common for silicon anodes). These properties meet the requirements of lithium batteries for portable and electric-vehicle applications. These SiNWs-based binder free anodes and the SiNPs anodes have been cycled for over 200 cycles, exhibiting a stable cycle life. Loss of capacity, at 0.1 mA/cm2, is about 20% only indicating that at least 80% of the SiNWs and the SiNPs are still connected to the substrate. It was found that both the SEI and the diffusion impedance grow with cycling. The thickness of a freshly formed SEI on lithium or on other substrates such as nickel, copper, stainless steel and carbon is a few nanometers only (the tunneling range of electrons (Peled 1979). During open circuit voltage conditions, and further exacerbated on cycling, the thickness and the resistance of the SEI grow with time. It was found that all measured parameters for the 3D SiNWs anode: Rsei, ρsei and SEI thickness grow with cycle number. For example: the SEI thickness after one and eleven cycles is 22 and 72 nm respectively and SEI resistance, of lithiated SiNWs anodes, grows from 17.8 (first cycle) to over 109 ohms.cm2 (after 71 cycles). The structure and composition changes of the SiNWs, the SiNPs and of the SEI will be reported.
Capacity Fading Mechanisms of Submicron-Sized Silicon Negative Electrode for Lithium Ion Batteries
Authors: Yoon Taeho , Lucht Brett L , Nguyen Cao Cuong , Seo Daniel
Published: February 2020

Silicon, due to its large specific capacity, is regarded as one of the most promising negative electrode materials for lithium ion batteries despite critical drawbacks associated with large volume change upon lithiation/de-lithiation. Although nano-sized silicon particles have been employed to mitigate the failures and related techniques have achieved considerable improvements, current materials do not meet the demand of commercial applications. Thus, a systematical approach to elucidating failure mechanisms is necessary to further improve electrochemical performances of the silicon electrode. Here, the evolution of voltage profiles recorded during cycling was thoroughly analyzed and thereby the failure mechanisms are proposed. The main failure mechanism of the silicon electrode is related to an inability to fully de-lithiate due to resistance increases during discharging, which are mostly contact and SEI resistance. The capacity retention was significantly improved by lowering discharge cut-off voltage and by introducing electrolyte additives, in which reduce the resistances during discharging.
(Invited) Ion Transport in Graphite Composite Electrode
Authors: Abe Takeshi , Miyazaki Kohei , Fukutsuka Tomokazu , Maruyama Shohei
Published: February 2020

Increasing concerns about environmental and energy problems accelerate the demands for high-energy-density batteries. Lithium-ion batteries (LIB) have large energy densities and have been well applied on not only portable devices such as smart phones but also electronic vehicles (EV). However, the energy densities of present LIBs for EV-use seem not to satisfy for a long cruising distance. Present LIBs for EV-use possess large power densities by the sacrifice of energy densities in order to shorten the charging time. In the practical LIBs for portable devices, dense and thick composite electrodes are used. In this case, the ion transport of electrolyte solution through the pores in the composite electrodes becomes a slow process. In order to enhance the energy densities with remaining high power densities, the ion transport rate should be increased for the dense and thick composite electrodes. Unfortunately, to develop dense and thick electrodes with high power densities, fundamental understanding of the ion transport in composite electrodes has not been clear. In this study, ion transportation behavior was investigated with ac impedance spectroscopy. In a conventional use of ac impedance spectroscopy, a composite electrode is used as a working electrode of the measurement cell. In this case, the result of impedance spectroscopy contains all resistances and capacitances accompanying the whole of the charge and discharge reaction including ion transfer through electrolyte and active materials, ion diffusion within active materials, etc. To focus on the impedance of ion transportation of electrolyte, it must be discriminated from that derived from other reaction steps. In order to obtain impedance spectra derived from only ion transportation, composite electrodes without a current collector were used. As a result, we obtained semi-circles, and this semi-circle was assigned to the ion transport process through the graphite composite electrode. As the potential went down, two semi-circles were observed. The characteristic frequency and the resistance of the semi-circle at higher frequency almost did not change. However, at lower frequency, the characteristic frequency and resistance changed. Further, we used a model electrode to understand the semi-circles. The detail analysis will be presented at the meeting.
Cyclic Carbonate Additives Effect on the Solid Electrolyte Interphase of Li Ion Batteries
Authors: Tavassol Hadi , Esbenshade Jennifer , Gewirth Andrew A.
Published: February 2020

We report on the effect of vinylene carbonate (VC) and vinyl ethylene carbonate (VEC) electrolyte additives on the formation, stability and Li+ transport properties of solid electrolyte interphase (SEI). The SEI is thought to consist of an inner inorganic part with an outer organic layer, likely formed via oligomerization of the solvent, which may change in the presence of additives.

Our analysis of a Au model anode system in a 1 M LiClO4/propylene carbonate electrolyte solution with and without additive molecules shows that additives influence the lithiation current, as well as the mass and rigidity of the SEI film. Addition of the additive molecules increases the lithiation current. VC-containing solutions exhibit the highest lithiation currents. Interestingly, when comparing the additive containing electrolytes, increasing the concentration of additives causes an over-potential for the lithiation, which results in lower lithiation currents. These preventive effects are more pronounced in VEC containing electrolytes. Our results suggest that addition of additive molecules, influences the performance of Li ion batteries in part by modifying the SEI rigidity. Addition of VC decreases film rigidity, while providing a stable protective layer, which improves stability of the SEI film.
Structural Analysis for Lithium Ion Conduction in Li-P-S Solid Electrolyte
Authors: Mitsui Akio , Ohara Koji , Mori Masahiro , Onodera Yohei , Koyama Yukinori , Arai Hajime , Uchimoto Yoshiharu , Ogumi Zempachi
Published: February 2020

Introduction and Result

 Batteries are used to power electric and hybrid electric vehicles, and to store a wind and solar energy in smart grids. The research and development of electrical vehicles has been an important subject. All solid batteries and solid electrolyte are key technologies for electric powered vehicles. Thus, drastic improvement in the performance of the rechargeable batteries is strongly needed. We focused on Thio-LISICON as Li2S-P2S5 glass system. This system was already reported that has similar local structure and differential lithium ion conductivities [1-2]. We think that lithium ion conduction is influenced array of local structure as total glass structure. However, it is not clearly.

 In this study, we researched the local structure of (Li2S)
x
(P2S5)
100-x
glasses (x = 67, 70 and 75).  We model the atomic and electronic structure of the glasses by density functional theory and reverse Monte Carlo simulations using synchrotron X-ray diffraction, Time of flight type neutron diffraction and Raman spectroscopy data. To obtain a reliable structural model, it is worth noting that local structure information from Raman spectroscopy are included in our study. The agreement with experimental X-ray and neutron structure factors is excellent as shown in Figure 1. Intriguingly, although a characteristic difference has been reported, pair correlation functions as Li-Li is similar. Since Pair correlation function as Li-P is reflected coordination state for lithium and PxSypolyhedron as shown in Figure 2, such coordination state would influence the lithium ion conduction as an electrochemical characteristic of the glass solid electrolyte. For structure detail, we will make a presentation on the day.

 In summary, we succeeded in the modeling the glass structure and discussion lithium diffusion mechanism in glass solid electrolyte.

Acknowledgment:

This work was partially supported by the RISING project of the New Energy and Industrial Technology Development Organization (NEDO).

 

References:

[1] Y. Onodera, et al. Journal of the Physical Society of Japan 81 (2012) 044802.

[2] K. Mori, et al. Chemical Physics Letters 584 (2013) 113–118

Figure 1
Problems at the Electrolyte-Electrode Interfaces in All-Solid-State Li-Ion Batteries : Insight from First-Principles Computation
Authors: Mo Yifei
Published: February 2020

All-solid-state batteries using solid electrolyte materials provide intrinsic safety and high energy density. Problems at the interfaces between the electrode and electrolyte materials, such as high interfacial resistance and interfacial degradation, are limiting the development of all-solid-state batteries. Computational modeling based on first principles methods can provide valuable insights into the fundamental mechanisms regarding both thermodynamics and kinetics at the solid interfaces. In this talk, I will present our recent computational study about the solid-solid interfaces in all-solid-state Li-ion batteries. Our first-principles modeling study reveals the compatibility issues of the electrolyte and electrode which lead to the failure of sulfide and oxide solid electrolyte materials. We will also discuss how to resolves these interfacial problems using the insights from first-principles computation.
Phosphorus-Containing Electrolytes - Expansion to Include Phosphoranimines for Li-Ion Batteries
Authors: Dufek Eric J. , Klaehn John R. , McNally Josh S. , Rollins Harry W.
Published: February 2020

The use of organic carbonates as the principle solvent component in electrolytes for Li-ion batteries (LIBs) has been well established. For low to medium voltage applications these compounds are effective, yet for high voltage applications, issues arise. Other problems, associated with the overall safety and stability of carbonate-based electrolytes, have also been observed. Small and highly oxygenated carbonates are both volatile and combustible. This combination is ill-suited for applications where a high level of safety is desired, such as in electric vehicles. To improve battery safety there has been significant interest in phosphorus-containing electrolytes due to their inherent non-flammability. Included in this broad class of electrolyte components are phosphazenes which contain a phosphorus-nitrogen (P=N) bond. Previous work in the energy storage arena has looked at the use of poly-phosphazenes as electrolyte additives, polymeric electrolytes and as electrode components.

            As electrolyte components, poly-phosphazenes, including cyclotriphosphazenes, have been shown effective at mitigating safety issues and in enhancing electrolyte stability.1 While successful, these compounds possess limitations related to total loading capacity in the electrolyte and also experience decreased performance at intermediate cycling rates. In order to alleviate some of the issues associated with the larger cyclotriphosphazenes, recent research has shifted to the investigation of linear phosphoranimines which contain a single P=N unit. These compounds which have lower molecular weight than other poly-phosphazenes, show promise in negating some of the limitations associated with the larger molecules.  The initial electrochemical, chemical and physical characterization of phosphoranimines will be presented.

 

H. W. Rollins, M. K. Harrup, E. J. Dufek, D. K. Jamison, S. V. Sazhin, K. L. Gering, et al., J. Power Sources, 263 (2014) 66-74
Non-aqueous Redox Flow Batteries for Grid Storage
Authors: Brushett Fikile R.
Published: February 2020

Energy storage is an increasingly valuable asset for electric grids composed of high fractions of intermittent sources, such as solar or wind-generated power, or, in developing economies, unreliable generation and transmission services.  Electrochemical technologies offer a pathway to high performance low cost storage but present state-of-the-art systems are too expensive for widespread deployment [1].  This motivates the search for new energy storage concepts with transformational potential.  To this end, the Joint Center for Energy Storage Research (JCESR) pursues discovery, design, prototyping, and commercialization of next generation beyond Li-ion batteries [2].  JCESR is targeting electrochemical energy storage at a cost of $100/kWh while achieving a 20-year calendar life of up to 7000 cycles at C/5, and having safety standards comparable to a natural gas turbine.  To deliver on these aggressive performance targets, a cohort of JCESR researchers have aligned their R&D activities under the umbrella of the Grid-arc covering the spectrum from discovery to manufacturing.  This presentation aims to provide an overview of these activities while highlighting key advances in the pursuit of JCESR’s three Legacies: (1) to advance the library of fundamental knowledge of materials and phenomena of energy storage, (2) to deliver a prototype capable of meeting JCESR’s performance targets, and (3) to establish a new paradigm for battery R&D.

References

[1]  R.M. Darling, K.G. Gallagher, J.A. Kowalski, S. Ha, F.R. Brushett, “Pathways to low-cost electrochemical energy storage: a comparison of aqueous and nonaqueous flow batteries”, Energy Environ. Sci., 2014, 7, 3459-3477.

[2]  G. Crabtree, “The Joint Center for Energy Storage Research: A New Paradigm for Battery Research and Development”, AIP Conf. Proc., 2015, 1652, 112-128.
Structures, Devices, and Architectures for Nanoscale Solutions in Electrical Energy Storage
Authors: Rubloff Gary W , Lee Sang Bok
Published: February 2020

Nano science and technology promise enhancement to batteries and capacitors through higher power at given energy, accompanied by new possibilities for better capacity retention and safety.  Among the challenges to realize this promise are (1) the design of higher performance electrode and electrolyte materials and (2) the rational design of structures in which these materials are arranged.  In Nanostructures for Electrical Energy Storage (NEES, www.efrc.umd.edu), we have focused on the latter, seeking to understand how the structure of components and the architecture in which they are arranged determine the multifunctionality required for electrical energy storage: ion transport and storage, electron transport, and structural stability during charge/discharge cycling.

Precision multistep synthesis has enabled the creation of heterogeneous nanostructures, involving multiple materials to confer the needed multifunctionality and to understand how design influences electrochemical behavior at the nanoscale and storage performance of nanostructures.   This is illustrated by several such structures which address fundamental phenomena important at the nanoscale and the mesoscale, including: (1) nanowire and nanotube structures with integrated electron transport components that achieve robust Li cycling despite large volume changes; (2) nanopore battery configurations to assess fundamental limits on ion transport in highly confined environments; (3) solid state electrolyte and battery configurations for scaling safe materials to the nanoscale; and (4) 3D nanostructure forests, both regular and pseudo-random, to analyze mesoscale architectures and new scientific challenges emerging at the mesoscale. These experimental advances have been accompanied by significant modeling and simulation insights, from DFT to continuum levels, and at the same time they pose formidable, important challenges for theory, particularly at the mesoscale.

This work has been supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award Number DESC0001160.

Figure 1
The Role of Ultrathin Coatings on the Interfacial Reactions at LiMn2O4 Surfaces
Authors: Elam Jeffrey W , Amine Khalil , Thackeray Michael M. , Curtiss Larry , Hersam Mark C. , Dravid Vinayak , Wolverton Chris , Gewirth Andrew A.
Published: February 2020

The spinel lithium manganese oxide (LiMn2O4, or LMO) is an established cathode technology for lithium ion batteries that suffers from a well-known phenomenon whereby Mn dissolves from the surface through the disproportionation reaction of Mn(III), and the subsequent deposition of Mn(II) on the anode.  LMO can serve as a model system for exploring various mitigation strategies that will enrich our understanding of electrochemical corrosion at charged interfaces in general and may ultimately lead to better batteries.  Consequently, the Center for Electrical Energy Science: Tailored Interfaces  (CEES, a DOE-funded Energy Frontier Research Center), is exploring the influence of ultrathin coatings and surface treatments on the interfacial reactivity during lithiation reactions in LMO by combining advanced synthesis, in situ probes, and theory.  As part of this effort, we have applied  single-layer graphene coatings to LMO films, and discovered that these coatings improve capacity retention following electrochemical cycling. X-ray photoelectron spectroscopy (XPS) depth profiling, reveals that the graphene coating inhibits manganese depletion in the LMO film. Additionally, cross-sectional TEM demonstrates that a stable solid-electrolyte interphase layer is formed on the graphene coating, which screens the LMO from direct contact with the electrolyte, thereby inhibiting dissolution. Density functional theory (DFT) calculations have provided plausible mechanisms for this behavior.  In a different effort, we have examined inert metal layers to prevent Mn dissolution.  We found that 3-nm-thick Au shells prepared by electroless deposition could reduce Mn dissolution by up to 88%.  Similarly, LiAlO2 thin films deposited on LiNi0.5Mn1.5O4 surfaces by atomic layer deposition can improve the electrochemical stability.  The LiAlO2 films are 100x more ionically conducting compared to Al2O3, and, consequently, provide a higher discharge capacity compared to Al2O3 and allow for higher rates.  Finally, we have explored the role of coherent coatings of a few nm-thick surface LiMn2-xTixO4, deposited on LMO. This approach protects the bulk LMO from acid corrosion but is also electrochemically active and, therefore, maintains the ion and charge transport channels on the surface. The surface-doped LMO has >2-fold improvement in electrochemical performance with respect to uncoated LMO in terms of cyclability and capacity at elevated temperature.  In this presentation I will survey these ongoing research efforts into understanding the role of ultrathin coatings on interfacial reactions at LMO surfaces.

This work was supported as part of the Center for Electrical Energy Storage: Tailored Interfaces, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.
Electrochemical Evolution of the Surface and Subsurface Properties of Layered Nickel-Rich Oxide Cathodes
Authors: Piper Louis F.J. , Sallis Shawn , Pereira Nathalie , Mukherjee Pinaki , Cosandey Frederic , Huang Yiqing , Quackenbush Nicholas F. , Whittingham M. Stanley , Amatucci Glenn G
Published: February 2020

The limitation and degradation of the ionic and electronic transport across the positive electrode/electrolyte interface can potentially reduce the achievable capacity of Li-ion batteries.  This is evident for the layered oxides such as those based on nickel that operate outside the stability of today’s organic electrolytes.  The rise in impedance and capacity fade with cycling has been identified as a result of loss of electrical contact originating from the instability of electrode surface and decomposition of the electrolyte.  In this talk, we will discuss the surface and subsurface properties of LiNi0.8Co0.15Al0.05O2 (NCA). NCA provides a model system for correlating capacity fade with the formation and evolution of the cathode electrolyte interface with cycling.  Our studies directly compare x-ray spectroscopy, electron spectromicroscopy, and high-resolution electrochemical characterization of the same NCA electrodes as a function of both initial charging and extended cycling.   This research is supported by the Northeast Center for Chemical Energy Storage (NECCESS), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001294.
Enable High Energy-Density Lithium-Ion Battery Conversion Cathodes Based on Iron Fluorides Using Integrated in Situ Experimental and Computational Approaches
Authors: Jin Song
Published: February 2020

The large-scale deployment of renewable energy technologies critically depends on solving the intermittency of energy production methods with scalable and inexpensive energy-storage solutions. Lithium-ion battery (LIB) technology has been widely considered as the technology of choice to meet the future energy challenge. Conversion cathode materials represented by inexpensive iron fluorides (FeF2 and FeF3) and oxyfluorides hold the promise to significantly increase the energy density of current LIBs. However, despite significant experimental and theoretical efforts in recent years, this promise has yet to be realized due to the challenges of fast capacity decay and a large voltage hysteresis. Solving these challenges requires a better understanding of the electrochemical reaction mechanisms during battery operation, especially during recharge, which however has been surprisingly under-researched. Here I will report our comprehensive and integrated experimental and theoretical studies into the mechanisms controlling the nanoscale electrode conversion/reconversion. By holistically evaluating the results from operando 2D X-ray absorption near-edge structure spectroscopy (XANES) microscopy, operando X-ray absorption spectroscopy, in situ scanning transmission electron microscopy (STEM) and electron diffraction (ED), ex situ TEM/ED, and density functional theory simulations, we will present new insights into the conversion mechanisms of these materials. We will also discuss our recent progress in developing long-cycle-life nanostructured iron fluoride conversion cathodes, which is built on the insights gleaned from the integrated experiments and modeling above.
(Invited) Improving Cycle Life of High Capacity Alloy Anodes for Li-Ion and Na-Ion Batteries
Authors: Wang Chunsheng , Fan Xiulin , Zhu Yujie , Wang Jing , Mao Jiangfeng
Published: February 2020

The one critical challenge for development of high capacity electrodes in Li-ion batteries is the cycle life. Extensive efforts have been devoted to improve the cycling stability of Si, Sn, P and their compound anodes. The one of the most successful technology is the use of nanostructured materials. We used different strategy to enhance the cycle life of these high capacity anodes. In this talk, we will summarize our efforts in extending the cycle stability of Si, Sn, P and SnP3 anodes for Li-ion and Na-ion batteries.
Domain Modeling of Lithium-Rich Manganese Nickel Oxide By Reverse Monte Carlo Method
Authors: Kitamura Naoto , Kubo Yusuke , Ishida Naoya , Idemoto Yasushi
Published: February 2020

INTRODUCTION

   Lithium manganese nickel oxides with layered structures have been investigated actively in the last decade. Especially, materials with lithium-rich compositions, such as Li1.2Mn0.6Ni0.2O2, are regarded as promising candidates for a cathode active material of the lithium-ion battery, due to higher energy densities, lower costs than typical commercialized cathodes like LiCoO2-based materials. It is well-known that their electrochemical properties are affected by cation distributions in the crystals, such as a LiMn6domain in a transition-metal layer and a Ni-O domain due to a cation mixing of Li and Ni. Therefore, the domain structures have been studied recently by TEM, NMR, extended X-ray absorption fine structure (EXAFS) and so on.

   For deeper understanding of domain structures, we have focused on the Reverse Monte Carlo (RMC) modeling on crystals using the Bragg reflections and total scatterings simultaneously. In this work, we applied the RMC to lithium manganese nickel oxides with layered structures and then determined local (non-periodic) domain structures in intermediate range up to ca.10 Å in addition to average (periodic) host structures.

EXPERIMENTAL

   Lithium transition-metal oxides, such as Li1.2Mn0.6Ni0.2O2, were synthesized by a coprecipitation method. Phase identifications of the samples were carried out laboratorial X-ray diffraction measurements, and the metal compositions were investigated by the inductively-coupled plasma (ICP) technique. For the reverse Monte Carlo modeling on crystals, synchrotron X-ray diffraction/total scattering patterns were measured by BL02B2 and BL04B2 installed at SPring-8, Japan. By using both the Bragg profile and structure factors S
box(Q) which were degraded taking simulation-box sizes into account, we performed the RMC simulation with RMCProfile, and then analyzed domain structures of the specimens.

RESULTS AND DISCUSSION

   X-ray diffraction and ICP measurements confirmed that the Li1.2Mn0.6Ni0.2O2 had a single phase of the Li2MnO3-type layered structure and the analytical metal composition was almost equal to the nominal value.

   For the purpose of a domain modeling in the crystal, we measured both the Bragg profile with high reciprocal-space resolution and the total scattering pattern with wide Q range. By using both the Bragg data and the convolved S
box(Q), the RMC simulation was carried out. Figure 1 shows results of the RMC for Li1.2Mn0.6Ni0.2O2. It is demonstrated that the RMC modeling can be performed successfully. From the simulated atomic configuration, we obtained pair distribution functions g(r) and then analyzed them. As a result, it is found that there is a correlation around 4 Å in g
Ni-Ni(r). This indicates that a Ni-O domain is formed in the crystal.

Figure 1
Electrochemical Properties of Ordered, Two-Dimensional, Double Transition Metals Carbides (MXenes)
Authors: Beidaghi Majid , Anasori Babak , Gogotsi Yury , Barsoum Michel W.
Published: February 2020

Two dimensional (2D) transition metal carbides (MXenes) are a new family of nanomaterials with a very high potential as electrode materials for batteries and electrochemical capacitors (ECs). These materials are labeled MXene because they are obtained by selectively etching of the A-layers from their 3D layered, parent compounds the Mn+1AXn, or MAX, phases, where M is an early transition metal, A is an A-group element, such as Al or Si, X is carbon and/or nitrogen and n is 1 to 3. The excellent performance of MXenes as electrode materials for ECs was recently reported in the case of Ti3C2.1,2 Here, we report on the synthesis and electrochemical properties of the ordered MXenes, Mo2TiC2 and Mo2TiC3, wherein the Mo atoms are on the surface and the Ti atoms are between the Mo. The volumetric capacitance of freestanding electrodes fabricated by vacuum filtration of 2D Mo2TiC2 sheets, was about 400 F/cm3.

(1)      Lukatskaya, M. R.; Mashtalir, O.; Ren, C. E.; Dall’Agnese, Y.; Rozier, P.; Taberna, P. L.; Naguib, M.; Simon, P.; Barsoum, M. W.; Gogotsi, Y. Cation Intercalation and High Volumetric Capacitance of Two-Dimensional Titanium Carbide. Science (80-. ).
2013, 341, 1502–1505.

(2)      Ghidiu, M.; Lukatskaya, M. R.; Zhao, M.-Q.; Gogotsi, Y.; Barsoum, M. W. Conductive two-dimensional titanium carbide “clay” with high volumetric capacitance. Nature
2014, 516, 78–81.
Redox-Active Xerogels As Pseudocapacitve Electrodes with Excellent Cycling Performance
Authors: Boota Muhammad , Bécuwe Matthieu , Gogotsi Yury
Published: February 2020

Electrochemically active organic molecules are emerging materials for small- to large-scale energy storage applications due to their low cost, recyclability, safety, and low toxicity. 1,2 In addition, they are compatible with various conductive substrates and their electrochemical properties can be tuned using established organic chemistry principals. 3,4 However, their poor conductivity and degradation upon cycling hamper the development of redox-active molecules/polymers for supercapacitors. Among all electroactive molecules, quinone-functionality is especially attractive due to its fast 2 e-/2 H+ redox reactions, and its ability to increase the capacitance of the double-layer capacitors. 1,5

Here, we synthesized conductive redox active xerogel by incorporating 2,5-dimethoxy-1,4-benzoquinone (DMQB) on reduced graphene oxide  (rGO) sheets via hydrothermal method. The physisorbed DMQB on rGO sheets via π-π stacking interactions was characterized via various spectroscopic and electrochemical methods. DMQB anchored rGO sheets exhibited high gravimetric capacitance of 1100 F/g, which exceeded pristine rGO sheets by the factor of five. Furthermore, DMQB@rGO based electrodes showed negligible IR drop, low ESR values and good columbic efficiency. Most importantly, electrodes showed negligible capacitance loss when cycled up to 25,000 cycles.   

1. B. Huskinson et al., Nature, 505, 195–8 (2014).

2. K. B. Hatzell, M. Boota, E. C. Kumbur, and Y. Gogotsi, J. Electrochem. Soc., 162, A5007–A5012 (2015).

3. M. Boota, K. B. Hatzell, E. C. Kumbur, and Y. Gogotsi, ChemSusChem, 8, 835–843 (2015).

4. S. E. Burkhardt et al., Energy Environ. Sci., 5, 7176 (2012).

5. D. Vonlanthen, P. Lazarev, K. a. See, F. Wudl, and A. J. Heeger, Adv. Mater., 26, 5095–5100 (2014).
New Generation High Performance Lithium-Ion Capacitor Laminate Cells
Authors: Cao Wanjun , Chen Xujie
Published: February 2020

In recent years considerable research has been focused on the development of high energy density EC capacitors. Among all the energy storage systems that have been investigated and developed in the last few years, Lithium-ion Capacitors (LICs) have emerged to be one of the most promising because LICs achieve higher energy density than conventional Electric Double-Layer Capacitors (EDLCs), and better power performance than Li-ion batteries (LIBs) as well being capable of long cycle life which is shown in Fig. 1. LICs contain a pre-lithiated LIB anode electrode and an EDLC cathode electrode. Previously, we have reported a LIC with activated carbon (AC) cathode and hard carbon (HC)/stabilized lithium metal powder (SLMP) anode electrodes with high energy density, high power density and long cycle life1-7. From all the study before, we have achieved a high energy density LIC pouch cell4 with an energy density as high as 30 Wh kg-1 but only with a usable specific power of about 1.0 kW kg-1 and a maximum specific power of 2.0 kW kg-1. Therefore in this paper, we wish to report new generation high performance LIC laminate cells with higher power density and longer cycle life by sacrificing the energy density of the cells. The low temperature performance of the LIC laminate cells is also included in this paper. It can be concluded from the following data figures (from Fig. 2 to Fig. 4) that the specific energy and energy density as high as 20 Wh kg-1 and 38 Wh L-1 have been achieved, respectively. The laminate cells obtained a maximum specific power of 7.8 kW kg-1, respectively. The developed LICs can operate in a temperature as wide as from -40 degree C to +70 degree C. After 50,000 cycles, the LIC laminate cells still have 92% of the initial discharge capacity.

References:

1. J.P. Zheng and W.J. Cao, The 20th International Seminar on Double Layer Capacitors and Similar Energy Storage Devices, Florida Educational Seminars Inc. (2010).

2. W.J. Cao, J.P. Zheng, J. Power Sources, 213, (2012) 180.

3. W.J. Cao and J.P. Zheng, J. Electrochem. Soc. 160, (2013) A1572.

4. W.J. Cao, J. Shih, J.P. Zheng, T. Doung, J. Power Sources, 257, (2014) 388-393.

5. W.J. Cao, Y.X. Li, B. Fitch, J. Shih, J.P. Zheng, J. Power Sources, 268, (2014) 841-847.

6. W.J. Cao, J.S. Zheng, D. Adams, T. Doung and J.P. Zheng, J. Electrochem. Soc., 161(14), (2014) A2087-A2092.

7. W.J. Cao, M. Greenleaf, Y.X. Li, D. Adams, M. Hagen, T. Doung, J.P. Zheng, J. Power Sources, 280, (2015) 600-605.

Figure 1