This document discusses emerging techniques for characterizing electrical energy storage devices with high spatial and temporal resolution. It describes how neutron scattering, X-ray scattering, electron microscopy, nuclear magnetic resonance, and nonlinear laser techniques can provide insights into chemical and physical phenomena over broad time and length scales. Developing combinations of in situ techniques with both high spatial resolution (down to the atomic scale) and high temporal resolution (down to the femtosecond range) could lead to improvements in battery and capacitor performance and a better understanding of failure mechanisms.
Effect of morphology on the photoelectrochemical performance of nanostructure...Pawan Kumar
Cu2O is a promising earth-abundant semiconductor photocathode for sunlight-driven water splitting. Characterization results are presented to show how the photocurrent density (Jph), onset potential (Eonset), band edges, carrier density (NA), and interfacial charge transfer resistance (Rct) are affected by the morphology and method used to deposit Cu2O on a copper foil. Mesoscopic and planar morphologies exhibit large differences in the values of NA and Rct. However, these differences are not observed to translate to other photocatalytic properties of Cu2O. Mesoscopic and planar morphologies exhibit similar bandgap (e.g.) and flat band potential (Efb) values of 1.93 ± 0.04 eV and 0.48 ± 0.06 eV respectively. Eonset of 0.48 ± 0.04 eV obtained for these systems is close to the Efb indicating negligible water reduction overpotential. Electrochemically deposited planar Cu2O provides the highest photocurrent density of 5.0 mA cm−2 at 0 V vs reversible hydrogen electrode (RHE) of all the morphologies studied. The photocurrent densities observed in this study are among the highest reported values for bare Cu2O photocathodes.
Effect of morphology on the photoelectrochemical performance of nanostructure...Pawan Kumar
Cu2O is a promising earth-abundant semiconductor photocathode for sunlight-driven water splitting. Characterization results are presented to show how the photocurrent density (Jph), onset potential (Eonset), band edges, carrier density (NA), and interfacial charge transfer resistance (Rct) are affected by the morphology and method used to deposit Cu2O on a copper foil. Mesoscopic and planar morphologies exhibit large differences in the values of NA and Rct. However, these differences are not observed to translate to other photocatalytic properties of Cu2O. Mesoscopic and planar morphologies exhibit similar bandgap (e.g.) and flat band potential (Efb) values of 1.93 ± 0.04 eV and 0.48 ± 0.06 eV respectively. Eonset of 0.48 ± 0.04 eV obtained for these systems is close to the Efb indicating negligible water reduction overpotential. Electrochemically deposited planar Cu2O provides the highest photocurrent density of 5.0 mA cm−2 at 0 V vs reversible hydrogen electrode (RHE) of all the morphologies studied. The photocurrent densities observed in this study are among the highest reported values for bare Cu2O photocathodes.
Organometal halide perovskite solar cells: Degradation and stabilityTaame Abraha Berhe
Organometal halide perovskite solar cells have evolved in an exponential manner in the two key areas of
efficiency and stability. The power conversion efficiency (PCE) reached 20.1% late last year. The key disquiet
was stability, which has been limiting practical application, but now the state of the art is promising, being
measured in thousands of hours. These improvements have been achieved through the application of
different materials, interfaces and device architecture optimizations, especially after the investigation of hole
conductor free mesoporous devices incorporating carbon electrodes, which promise stable, low cost
and easy device fabrication methods. However, this work is still far from complete.
This presentation is a simple explain of Nano-springs which introduce this Nano-materials easily. You can use this PPTx File to present in your class and seminars as well. We prepare this file to present in Tabriz University of Medical Sciences when We were MSc Medical Nanotechnology student. It will be useful for you too.
Exploiting the potential of 2-((5-(4-(diphenylamino)- phenyl)thiophen-2-yl)me...Akinola Oyedele
A comprehensive experimental study is reported on the optical and electrical characteristics of 2-((5-(4-
(diphenylamino)phenyl)thiophen-2-yl)methylene)malononitrile (DPTMM) when used as molecular donor
in an organic solar cell (OSC) device structure.
Advantages and problems of perovskite solar cellalfachemistry
This article mainly introduces the advantages and problems of perovskite solar cell. Visit https://www.alfa-chemistry.com/products/perovskite-solar-cells-139.htm for more information.
Perovskite Solar Cells
a short general overview presentation
hadi maghsoudi
device structure
crystal structure
preparation synthesis method
review papers
Research proposal on organic-inorganic halide perovskite light harvesting mat...Rajan K. Singh
Organic-Inorganic perovskite materials has many applications in the field of opto-electronics such as photo-voltaic cells, LEDs, sensors, memory devices etc. due to its excellent optical and electrical properties. Presence of Pb in such type of perovskite is the biggest challenge for researchers.
Amorphous-nano-crystalline silicon composite thin films (a-nc-Si:H) samples were synthesized by
Plasma Enhanced Chemical Vapor Deposition technique. The measurement of DC conductivities was
accomplished using Dielectric spectroscopy (Impedance Spectroscopy) in wide frequency and temperature range.
In analysis of impedance data, two approaches were tested: the Debye type equivalent circuit with two parallel R
and CPEs (constant phase elements) and modified one, with tree parallel R and CPEs including crystal grain
boundary effects. It was found that the later better fits to experimental results properly describes crystal grains
dielectric effect and hydrogen concentration indicating presence of strain. The amorphous matrix showed larger
resistance and lower capacity than nano-crystal phase. Also it was found that composite silicon thin film cannot
be properly described by equivalent circuit only with resistors and constant phase elements in serial relation
Organometal halide perovskite solar cells: Degradation and stabilityTaame Abraha Berhe
Organometal halide perovskite solar cells have evolved in an exponential manner in the two key areas of
efficiency and stability. The power conversion efficiency (PCE) reached 20.1% late last year. The key disquiet
was stability, which has been limiting practical application, but now the state of the art is promising, being
measured in thousands of hours. These improvements have been achieved through the application of
different materials, interfaces and device architecture optimizations, especially after the investigation of hole
conductor free mesoporous devices incorporating carbon electrodes, which promise stable, low cost
and easy device fabrication methods. However, this work is still far from complete.
This presentation is a simple explain of Nano-springs which introduce this Nano-materials easily. You can use this PPTx File to present in your class and seminars as well. We prepare this file to present in Tabriz University of Medical Sciences when We were MSc Medical Nanotechnology student. It will be useful for you too.
Exploiting the potential of 2-((5-(4-(diphenylamino)- phenyl)thiophen-2-yl)me...Akinola Oyedele
A comprehensive experimental study is reported on the optical and electrical characteristics of 2-((5-(4-
(diphenylamino)phenyl)thiophen-2-yl)methylene)malononitrile (DPTMM) when used as molecular donor
in an organic solar cell (OSC) device structure.
Advantages and problems of perovskite solar cellalfachemistry
This article mainly introduces the advantages and problems of perovskite solar cell. Visit https://www.alfa-chemistry.com/products/perovskite-solar-cells-139.htm for more information.
Perovskite Solar Cells
a short general overview presentation
hadi maghsoudi
device structure
crystal structure
preparation synthesis method
review papers
Research proposal on organic-inorganic halide perovskite light harvesting mat...Rajan K. Singh
Organic-Inorganic perovskite materials has many applications in the field of opto-electronics such as photo-voltaic cells, LEDs, sensors, memory devices etc. due to its excellent optical and electrical properties. Presence of Pb in such type of perovskite is the biggest challenge for researchers.
Amorphous-nano-crystalline silicon composite thin films (a-nc-Si:H) samples were synthesized by
Plasma Enhanced Chemical Vapor Deposition technique. The measurement of DC conductivities was
accomplished using Dielectric spectroscopy (Impedance Spectroscopy) in wide frequency and temperature range.
In analysis of impedance data, two approaches were tested: the Debye type equivalent circuit with two parallel R
and CPEs (constant phase elements) and modified one, with tree parallel R and CPEs including crystal grain
boundary effects. It was found that the later better fits to experimental results properly describes crystal grains
dielectric effect and hydrogen concentration indicating presence of strain. The amorphous matrix showed larger
resistance and lower capacity than nano-crystal phase. Also it was found that composite silicon thin film cannot
be properly described by equivalent circuit only with resistors and constant phase elements in serial relation
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
Fabrication and studying the dielectric properties of (polystyrene-copper oxi...journalBEEI
The preparation of (polystyrene-copper oxide) nanocomposites have been investigated for piezoelectric application. The copper oxide nanoparticles were added to polystyrene by different concentrations are (0, 4, 8 and 12) wt.%. The structural and A.C electrical properties of (PS-CuO) nanocomposites were studied. The results showed that the dielectric constant and dielectric loss of (PS-CuO) nanocomposites decrease with increase in frequency. The A.C electrical conductivity increases with increase in frequency. The dielectric constant, dielectric loss and A.C electrical conductivity of polystyrene increase with increase in copper oxide nanoparticles concentrations. The results of piezoelectric application showed that the electrical resistance of (PS-CuO) nanocomposites decreases with increase in pressure.
Electron Diffusion and Phonon Drag Thermopower in Silicon NanowiresAI Publications
The field of thermoelectric research has undergone a renaissance and boom in the fast two decades, largely fueled by the prospect of engineering electronic and phononic properties in nanostructures, among which semiconductor nanowires (NWs) have served both as an important platform to investigate fundamental thermoelectric transport phenomena and as a promising route for high thermoelectric performance for device applications. In this report we theoretical studied the carrier diffusion and phonon-drag contribution to thermoelectric performance of silicon nanowires and compared with the existing experimental data. We observed a good agreement between theoretical data and experimental observations in the overall temperature range from 50 – 350 K. Electron diffusion thermopower is found to be dominant mechanism in the low temperature range and shows linear dependence with temperature.
Laser ablation - optical cavity isotopic spectrometer (LAOCIS) for Mars roversAlexander Bolshakov
Proceedings of SPIE, v. 8385, "Sensors and Systems for Space Applications V"; Baltimore, MD, 2012. ABSTRACT: A concept of a compact device for analyzing key isotopic composition in surface materials without sample preparation is presented. This design is based on an advanced modification of Laser Induced Breakdown Spectroscopy (LIBS). First, we developed Laser Ablation Molecular Isotopic Spectrometry (LAMIS) that involves measuring isotope-resolved molecular emission, which exhibits significantly larger isotopic spectral shifts than those in atomic transitions. Second, we used laser ablation to vaporize the sample materials into a plume in which absorption spectra can be measured using a tunable diode laser. The intrinsically high spectral resolution of the diode lasers facilitates measurements of isotopic ratios. The absorption sensitivity can be boosted using cavity enhanced spectroscopy. Temporal behavior of species in a laser ablation plasma from solid samples with various isotopic composition was studied. Detection of key isotopes associated with signs of life (carbon, nitrogen, hydrogen) as well as strontium and boron in laser ablation plume was demonstrated; boron isotopes were quantified. Isotope-resolved spectra of many other molecular species were simulated. The experimental results demonstrate sensitivity to 86 Sr, 87 Sr, and 88 Sr with spectrally resolved measurements for each of them. It is possible to measure strontium isotopes in rocks on Mars for radiogenic age determination. Requirements for spectral resolution of the optical measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra.
The Effect of RF Power on ion current and sheath current by electrical circui...irjes
Plasma is very important in the development of technology as it is applied in many electronic devices
such as global positioning system (GPS). In addition, fusion and process of plasma requires important elements,
namely, the electron energy distribution. However, plasma glow is a relatively new research field in physics.
There has not been found any previous study on the electric plasma modeling. Thus, this study was aimed to
study plasma modeling especially to find out what was the difference in the number of density and the
temperature of the electron in the plasma glow before and after heated and to discover how was the distribution
of electron and ion in the plasma. This research was conducted at Brawijaya University, Malang, Indonesia in
the Faculty of Science. This exploration began in the middle of June 2013. The data collection and data analysis
were done during a year around until August 2014. In this research, characteristics of plasma were studied to
build model of plasma. It utilized MATLAB dialect program examination framework which result in the
distribution of temperature and current density. The findings show that there has been a large increase in the
number of U, U2 with power, while figures of U1 is stable until middle of curve and then decrease as u but u2
after increase at point then stable. The differences appearing are probably due to the simplifying assumptions
considered in the present model. There was a curve between current in sheath and plasma. And time and sheath
current increased in the beginning then decreased before they experienced another increase.
Similar to Probing electrical energy storage chemistry and physics over broad time and length scales (20)
Hybrid resources: Challenges, Implications, Opportunities, and InnovationAndrew Gelston
Publication in the IEEE power & energy magazine November/December 2021 Issue on Hybrid renewable + Storage resources.
Layman explanation of why 1+1 = 3, rather then 2, with Hybrid co-optimizing internally as a single resource
NextEra Energy and Hawaiian Electric Industries to Combine (December 2014)Andrew Gelston
Achieving a More Affordable Clean Energy Future For Hawaii
Hawaiian Electric Industries Announces Plan to Spin off ASB Hawaii into an Independent Publicly Traded Company
December 3, 2014
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
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Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Probing electrical energy storage chemistry and physics over broad time and length scales
1. PROBING ELECTRICAL ENERGY STORAGE CHEMISTRY AND
PHYSICS OVER BROAD TIME AND LENGTH SCALES
Progress in microscopy, scattering, and spectroscopy has advanced our understanding of
chemical and interfacial processes. Revolutionary insights into the physico-chemical
phenomena that underlie the operation of energy storage devices require further optimization
of current methodologies and the development of new in situ photon- and particle-based
microscopic, spectroscopic, and scattering techniques with time resolution down to the
femtosecond range and spatial resolution spanning the atomic and mesoscopic scales.
Information derived from these measurements will lead to the rational design of batteries and
electrochemical capacitors (ECs), including materials and novel architectures that exhibit
optimal performance in terms of charge-discharge characteristics and capacities approaching
theoretical values. In addition, this information will help identify the underlying reasons
behind failure modes and afford directions for mitigating them. Examples are provided of
emerging techniques that illustrate potential research approaches toward meeting the
challenges in the area of in situ characterization.
INTRODUCTION
Electrical energy storage (EES) devices are complex multicomponent systems that
incorporate widely dissimilar phases in physical and electrical contact. The operation of
batteries and double layer capacitors relies critically on electron and ionic transfer across
solid–solid and solid–liquid interfaces and within each of the constituent phases. A
microscopic understanding of each of these elementary events could lead to dramatic
improvements in performance. The continuous charge and discharge of EES devices
invariably leads to performance degradation brought about by irreversible changes in the
structure, morphology, and composition of the materials, the nature and mechanism of which
has not yet been fully identified. Examples include the slow side reactions at highly polarized
electrodes, particularly anodes, that consume solvent and anions, forming films such as those
that occur at the solid electrolyte interphase (SEI) on lithium and Li-ion electrode surfaces.
Crucial to gaining a fundamental understanding of chemical energy storage phenomena is the
development and implementation of in situ photon- and particle-based (e.g., neutron)
spectroscopic, microscopic, and scattering techniques capable of the highest sensitivity and
structural and elemental specificity. These techniques would allow the monitoring of events
with time resolution down to femtoseconds and spatial resolution down to the mesoscopic
and atomic length scales. Novel multi-technique and in situ strategies are required that would
allow simultaneous imaging of structural, electrochemical, and physical/electronic properties
simultaneously to correlate atomic and electronic structure with reactivity. These novel
techniques would also allow researchers to exploit the inherent time dependence of the
electrochemistry experiment (e.g., the ability to pulse) that is sensitive to surfaces and
interfaces. The increased use of nanomaterials or nanocomposites in this field introduces new
challenges for characterization. A complementary approach that will assist in the elucidation
of the physico-chemical principles underlying the wide variety of involved phenomena relies
on the design of appropriate model systems more amenable to joint theoretical-experimental
analysis.
B-3
2. SCIENCE OPPORTUNITIES
Electronic and ionic transport across interfaces and within phases is crucial to the operation
of EES devices. Key elementary processes include (1) concerted electron and ion transport at
the interface between an electrolyte and an ion intercalation electrode and (2) the spatial and
temporal evolution of phase boundaries in single particles of charge storage materials. A
better understanding of the underlying principles that govern these phenomena is inextricably
linked to our ability to monitor in situ charge flow in real time and with high spatial
resolution. At present, a temporal gap exists between the time scales accessible to
electrochemical methods and those available to other characterization techniques, especially
structural.
Scanning probe microscopies make it possible to image surfaces with unprecedented
resolution, both in vacuum and in electrochemical environments. Extending these
microscopic techniques to the nano- and femtosecond time scales represents a tremendous
challenge with extraordinary repercussions in energy storage, catalysis, and other interfacial
disciplines. Scattering techniques that rely on long-range order face similar challenges (such
as diffraction) for monitoring nanometer-scale materials embedded in a host phase (such as a
particle of a Li-ion intercalation material incorporated in a composite electrode material).
New-generation synchrotron light sources and neutron reactors now under construction in the
United States, including the Spallation Neutron Source (SNS) at Oak Ridge National
Laboratory and NSLS-II at Brookhaven National Laboratory, will open new venues for
meeting these challenges. Surprisingly, little progress has been made toward the development
of electrochemical techniques with response times of less than 100 ns. This constraint is due
partly to the physical size of electrodes, because the time constant of the cell correlates
linearly with the radius size of the electrode-electrolyte interface. Another constraint is the
current lack of special electronic circuit designs to avoid undesirable induction and ground
loops.
POTENTIAL RESEARCH APPROACHES
Advances in experimental scattering, microscopy, and spectroscopy are required to meet the
desired spatial and temporal response characterization goals. Research that leverages
advances in each of these areas to fully exploit their potential for EES characterization should
be strongly encouraged. Additionally, the development of combinations of in situ high-spatial-
resolution and high-temporal-resolution techniques should serve as a prolegomenon
for future progress. Use of new characterization instrumentation will require the design,
engineering, and optimization of novel electrochemical cells with components that are
compatible with specific characterization techniques. The following subsection presents
selected examples that illustrate some of the research opportunities offered by emerging
instrumentation and methods.
Neutron-based techniques—Neutrons are ideally suited for high-specificity monitoring of
lithium, one of the most important components of a Li-ion battery. In particular, the coherent
neutron scattering lengths of 7Li and 6Li are negative and positive, respectively. Therefore,
the scattering contrast between a lithiated compound of interest and the background can be
eliminated by the appropriate choice of a 6Li and 7Li ratio (making the lithium essentially
“invisible”). It is then possible to focus on other components such as carbon or the organic
B-4
3. electrolytes, as demonstrated for 1H and 2H, and for 62Ni and natural abundance Ni in a Li-ion
battery material.1 The high flux and pulsed source of the SNS will allow smaller in situ
neutron diffraction cells to be developed so that smaller samples (or even single crystals) can
be studied under increasingly realistic timescales. New classes of experiments can now be
applied to battery materials. One-dimensional (area-averaged) compositional structures of
buried interfaces can be measured by neutron reflectometry through a chosen electrode under
in situ operating conditions. Neutron reflectometry allows direct observation of
electrochemically driven transformations, intercalation propagation fronts, kinetics, and
interface reconstruction/coarsening. Submicron lateral morphology changes can also be
observed simultaneously through grazing angle diffraction. At the SNS, single-cycle and
multicycle stroboscopic measurements will achieve subminute and subsecond temporal
resolution, respectively, providing new opportunities for monitoring the kinetics of a number
of processes. Three-dimensional architectures and self-assembled nano- and mesostructures
can be investigated using small-angle neutron scattering.
X-ray scattering—The development of improved beam optics with more focused beams,
(e.g., as proposed for development at NSLS-II) will allow spatially resolved experiments. For
example, the use of X-ray absorption spectroscopy (XAS) with significantly improved spatial
resolution (1–10 nm) will allow researchers to better understand batteries. While resonant
hard X-ray scattering (and reflectivity) are routinely used to locate the presence of heavy
metals such as iron and manganese, the emergence of resonant soft X-ray scattering
(RSOXS) experiments at a variety of synchrotron sources (e.g., the Advanced Light Source)
provides avenues for determining the specific locations of light elements such as carbon and
lithium. The extended X-ray absorption fine structure (EXAFS) method, which is sensitive to
short-range physical structure, will continue to play an important role in the in situ
characterization of local structure, particularly in disordered materials. The X-ray absorption
near edge structure (XANES) portion of XAFS reveals electronic properties and change in
the oxidation state. For example, Figure B.1 shows the iron, nickel, and cobalt K-edge
XANES obtained in situ for Li1-xCo1/3Ni1/3Mn1/3O2 as a function of the extent of Li-ion
intercalation during charging, illustrating the high element specificity of the technique. With
appropriate hardware and optics, it is possible to acquire spectra in a matter of seconds (quick
XAFS), facilitating the study of kinetic phenomena important in battery processes.
Diffraction anomalous fine structure is a promising development in XAS, offering the
capability to probe site-selective local structures for systems with chemically identical atoms.
Although it is difficult to apply to dilute systems, the higher brightness of third- and fourth-generation
synchrotron sources will make measurements, even in situ, feasible.
The higher-intensity synchrotron fluxes already available at the Advanced Photon Source
will continue to drive technique development. One such method—in situ pair distribution
function (PDF) analysis—should play a role in following conversion reactions of
nanoparticles. Diffraction measurements on single crystals will provide detailed mechanistic
information. These measurements are increasingly more feasible on smaller and smaller
crystallites because of current developments in synchrotron sources. The challenge of
characterizing the disorder inherent to many EES systems will continue to drive methods and
software development in this field. Results from techniques such as PDF analysis require
input from other structural local and long-range probes because the data become increasingly
B-5
4. Figure B.1. Normalized Mn(a), Ni(b), and Co(c) K-edges XANES of Li1-xCo1/3Ni1/3Mn1/3O2 as a
function of the amount of lithium in the lattice.2
more difficult to interpret as the systems become more complex and heterogeneous. These
methods require further development.
Microbeam small angle X-ray scattering (SAXS) in scanning probe mode is particularly
useful for investigating composite materials. In third- or fourth-generation synchrotrons, the
probe size can be brought below 1 micron to provide local information about solid-solid and
solid-liquid interfaces with time resolution that can reach microseconds. By acquiring SAXS
data above and below the absorption edge of a particular element in a so called “anomalous”
SAXS (ASAXS), scattering from that element can be isolated, allowing the direct location of
a particular element within the structure from the electron density (index) profile. For
example, in situ ASAXS measurements could be used to determine the size distribution of
metal/metal-oxide particles distributed in a porous carbon binder and possible changes in that
distribution as a function of the state of charge and cycle history. Resonant and nonresonant
X-ray Raman scattering can provide the same information as vacuum ultraviolet absorption,
determining the electronic structure by providing shallow core-level absorption spectroscopy
information, particularly the K-edge of oxygen and carbon and the L-edges of three-dimensional
transition metals, using hard X-rays, with the concomitant advantages of
sensitivity to small samples and in situ measurement.3
Electron microscopy—Electron microscopies have already made outstanding contributions
to the microstructural characterization of EES materials. Major goals in this field include the
development of aberration-free imaging methods in the nanometer range that can be used to
investigate battery materials, and the use of (elastic and inelastic) scattered electrons for the
structural and chemical analysis of materials at very high spatial resolution. The combination
of high local structural resolution with high local spectroscopic resolution in energy (e.g.,
EELS <0.2 eV resolution, <20 nm spot size) can allow different valence states in fully and
partially intercalated host materials to be distinguished and can allow impurity states and
bonding at interfaces at atomic dimensions to be characterized. High-resolution energy
filtered electron microscopy can be used to locate elements spatially, as illustrated for an
organic microphase separated block copolymer in Figure B.2. The instrumentation to
perform such measurement is available at several Department of Energy user facilities, such
as the National Center for Electron Microscopy and the Shared Research Equipment User
Facility (ShARE).
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5. B-7
Figure B.2. Imaging lithium in a block
copolymer electrolyte. Energy-filtered
electron micrograph. Bright regions show the
lithium-rich domains, confined to 20 nm
lamellae. (Pending patent application
PCT/US2007/0, “High Elastic Modulus
Polymer Electrolytes,” filed by the Regents of
the University of California, 4/3/2007.)
A new generation of dedicated aberration-corrected
transmission electron microscopes—
optimized for in situ experiments where the
effects of radiation damage, induced by the
high-energy electron beam, are minimized or
eliminated—is expected to provide a marked
improvement in all types of electron
microscopy techniques. The projected technical
progress in in situ high-resolution transmission
electron microscopy instrumentation,
environmental chambers, and improved
accessories and the development of advanced
specimen preparation methodologies will create
new and unique possibilities for dynamic
studies of electrode materials in the sub-nanometer
range. In situ, energy-filtered
imaging of specimens with well-defined
geometries will allow diffusion paths to be
followed (e.g., lithium ions in the crystalline
lattice). In situ, real-time imaging of dynamic processes induced by a local perturbation (e.g.,
a charge or mass transfer, mechanical stress) represents the longer-term goal for electron
microscopy, which requires new advanced experimental strategies. Recent advances in the
development of ultrafast electron microscopy and diffraction analysis with short pulses of
electrons (femto- and picoseconds) will further reduce the risk of damage to sensitive
specimens by the electron beam without compromising the quality of structural and chemical
characterization.
Nuclear magnetic resonance (NMR)—NMR, an element-specific probe of local structure,
is positioned to play an increasingly important role in characterizing both structure and
dynamics in the electrodes, electrolyte, and interfaces. The chemical, hyperfine, and Knight
shifts provide considerable detail concerning both the local structure and the electronic
environment in diamagnetic, paramagnetic, and metallic materials, respectively.4,5 The
application of in situ NMR methods to this field is still in its infancy, although in situ static
NMR has been used to study functioning battery cells,6 and in situ NMR cells for use in
electrocatalysis7,8 have been built. Similar NMR cells to study electrode-electrolyte interfaces
can be envisaged, which may allow researchers to unravel the dynamics of the interface
processes. Incorporating magic angle spinning into the design of an in situ cell will be a
challenge, but techniques developed in other fields could be adapted to this problem.
Nonlinear laser-based techniques—Simultaneous acquisition of topography and
spectroscopy images, from which local electrochemical current-voltage characteristics for a
fixed probe position can be determined, represents one future target for the development of
new concepts and dedicated surface analytical techniques. The objective is to combine the
high spatial resolution and versatility of scanning probe microscopy (SPM) with
electrochemical and/or spectroscopic local sensing ability. Multifunctional SPM probes
6. enable the direct correlation of structural information with chemical surface activity and
topography.
The combination of SPM and near-field scanning optical microscopy (NSOM) offers
significantly increased spatial resolution below the diffraction limit (20–100 nm), single-photon
sensitivity, simultaneous topographic characterization, and compatibility with optical
spectroscopies (Figure B.3). Individual nanostructures, which are too small for optical
imaging, can be characterized by inducing local excitations at a precise distance from the
nanostructure. Nano-Raman, surface-enhanced Raman, tip-enhanced resonant Raman,
infrared, second harmonic, photoluminescence, and fluorescence spectroscopies are suitable
for in situ local characterization of chemical and physical surface properties of EES
electrodes and surface layers at a subwavelength resolution and coverages down to
pmol/cm.2,9
Figure B.3. A multifunctional imaging nanoprobe.
Femtosecond laser pulse confocal microscopy or NSOM can be used to probe and monitor
order-disorder phase transition and relaxation processes in active materials via nonlinear
optical properties (e.g., through second harmonic generation at surfaces). Fast single-pulse
(instead of scanning methods) Raman mapping and imaging in the mid- and far-infrared
range represent a new class of tools with excellent high resolution (<100 nm) for in situ study
of the structure of porous materials, composites, and nanostructures used in chemical energy
storage systems.
B-8
7. Since most chemical reactions involve nuclear motions at a time scale of >10 fs, the ultrafast
spectroscopy/imaging techniques are required to resolve and follow the pathways of complex
reactions at the electrode-electrolyte interface. In situ infrared visible sum frequency
generation spectroscopy can probe solvent structure above a battery or capacitor electrode
and resolve the solvent molecules in environments associated with both the electrode surface
and the diffuse double layer.10
POTENTIAL IMPACT
Structural and spectroscopic techniques in the static and slow dynamics modes have reached
a high level of maturity because of the advent of high-intensity lasers and synchrotron
sources and linear and nonlinear optical techniques. It is now possible to determine a great
deal about the structure of the electrodes and electrolyte in EES devices at various states of
charge and discharge, cycle life, and other factors.
WORKS CONSULTED
1. J. Bréger, N. Dupré, P. J. Chupas, P. L. Lee, T. Proffen, J. B. Parise, and C. P. Grey,
“Short and long range order in the positive electrode material Li(NiMn)0.5O2: A joint
X-ray and neutron diffraction, pair distribution function analysis and NMR study,” J. Am.
Chem. Soc. 127 (20), 7529–7537 (2005).
2. W. S. Yoon, M. Balasubramanian, K. Y. Chung, X. Q. Yang, J. McBreen, C. P. Grey,
and D.A. Fischer, “Investigation of the charge compensation mechanism on the
electrochemically Li-ion deintercalated Li1-xCo1/3Ni1/3Mn1/3O2 electrode system by
combination of soft and hard X-ray absorption spectroscopy.” J. Am. Chem. Soc. 127,
17479–17487 (2005).
3. H. Hayashi, Y. Udagawa, J. Gillet, W. Caliebe, and C. Kao, “Chemical applications of
inelastic X-ray scattering,” in Chemical Application of Synchrotron Radiation, T.-K.
Sham, ed., World Scientific: Singapore, Vol. 12, p. 850, 2002.
4. C. P. Slichter, Principles of Magnetic Resonance. 3rd ed.; Springer-Verlag: Berlin,
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p. 655, 1990.
5. C. P. Grey and N. Dupre, “NMR studies of cathode materials for lithium-ion
rechargeable batteries,” Chem. Rev. 104, 4493–4512 (2004).
6. F. Chevallier, C. Clinard, E. Frackowiak, J. N. Rouzaud, F. Beguin, M. Morcrette, and
J. M. Tarascon, “The first in situ Li-7 nuclear magnetic resonance study of lithium
insertion in hard-carbon anode materials for Li-ion batteries,” J. Chem. Phys. 118,
6038–6045 (2003).
7. Y. Y. Tong, A. Wieckowski, and E. Oldfield, “NMR of electrocatalysts,” J. Phys.
Chem. B 106, 2434–2446 (2002).
8. B. M. Rush, J. A. Reimer, and E. J. Cairns, “Nuclear magnetic resonance and
voltammetry studies of carbon monoxide adsorption and oxidation on a carbon-supported
platinum fuel cell electrocatalyst,” J. Electrochem. Soc. 148, A137–A148 (2001).
9. K. F. Domke, D. Zhang, and B. Pettinger, “Toward Raman fingerprints of single dye
molecules at atomically smooth Au(111), J. Am. Chem. Soc. 128, 14721–14727 (2006).
10. Z. D. Schultz, S. K. Shaw, and A. A. Gewirth, “Potential dependent organization of water
at the electrified metal-liquid interface,” J. Am. Chem. Soc. 127, 15916–15922 (2005).