Ilke Arslan, Pacific Northwest National Laboratory
Eric Stach, Brookhaven National Laboratory
Yury Gogotsi, Drexel University
Liqiang Mai, Wuhan University of Technology
Symposium Support FEI Co
Fischione Instruments, Inc.
Wuhan University of Technology
FF2: In-situ and Operando Methods in Energy Storage I
Monday PM, December 02, 2013
Hynes, Level 3, Room 310
2:30 AM - FF2.01
The Effect of Bi Additives on Zn Morphology Imaged in situ Using Liquid Cell Transmission Electron Microscopy
Jeung Hun Park 1 2 Mark C. Reuter 2 Nicholas M. Schneider 3 Haim H. Bau 3 Daniel A. Steingart 4 Suneel Kodambaka 1 Frances M. Ross 2
1University of California Los Angeles Los Angeles USA2IBM T. J. Watson Research Center Yorktown Heights USA3University of Pennsylvania Philadelphia USA4Princeton University Princeton USAShow Abstract
The development of improved electrochemical energy storage devices depends critically on a detailed understanding of the physical and electrochemical processes at the electrode-electrolyte solid-liquid interface. Recent advances in in situ liquid cell electron microscopy, with its unique ability to provide simultaneous temporally and spatially resolved information as well as electrochemical parameters, enable exploration of the underlying physics of electrochemical reactions at the solid-liquid interface. Here we apply liquid cell electron microscopy to investigate the effect of additives on the morphology of electrochemical deposits. We have examined the deposition of zinc, an attractive anode material for low cost, recyclable batteries. Morphological control of zinc during deposition is required to avoid the formation of dendrites which may short the battery during charging. The inclusion of additives such as Bi in the electrolyte is known to modify the morphology and growth kinetics of Zn. Here, we use a liquid cell with three electrodes and the capability of liquid flow so that we can introduce acidic electrolytes of varying composition. We observe the deposition of Zn under galvanostatic conditions in electrolytes with different concentrations of the Bi additive, as well as changes in the Zn morphology when the additive is first supplied. We will compare these flow cell results to static liquid cell experiments (in a custom built liquid cell, the nanoaquarium) in which we have recorded Zn morphology during galvanostatic deposition, and we will discuss the benefits and pitfalls of flow capabilities in in situ electron microscopy for the study of processes during battery operation.
2:45 AM - FF2.02
Transmission Electron Microscopy in Ionic Liquids - Particle Motion Visualization
Ulrich Mansfeld 1 Stephanie Hoeppener 1 2 Ulrich S. Schubert 1 2
1Friedrich Schiller University Jena Jena Germany2Jena Center of Soft Matter (JCSM) Jena GermanyShow Abstract
Cryo-Transmission electron microscopy is regarded as a powerful tool for the investigation of samples in a solution-like state. Due to the rapid freezing of the samples the sample is trapped in a thin ice layer and can be imaged under mild imaging conditions. However, dynamical processes are also trapped in this frozen state and cannot be analyzed easily. There is a growing demand for the in-situ investigation of such events and recently the utilization of specially constructed liquid cells for the investigation of solutions and dynamic processes are frequently use. Because of the expenses as well as because of the rather thick boundaries of such liquid cells, which require the utilization of scanning transmission electron microscopy techniques, we introduce here a simple and straightforward technique for the in-situ observation of nano-objects in liquid environments. Ionic liquids are molten salt-like compounds which virtually have no vapor pressure and remain liquid over a wide range of temperatures. These ionic liquids are known as excellent solvents for many materials and are used in synthesis as well as alternative solvents for nanoparticles, cellulose derivatives, nanoparticles, etc.. They have been also used to study self-organization processes of block copolymers.
Due to the negligible vapor pressure ionic liquids are also compatible with the ultrahigh vacuum requirements of TEM and can be prepared as a free-standing liquid support film in which the visualization of particles or suspended nanostructures can be achieved. This approach permits the study of particle movement, crystal formation in ionic liquids, or the growth of nanoparticles. Additionally, it will be demonstrated that ionic liquids provide useful intrinsic staining properties, which enable the visualization of e.g. core-shell polymer nanostructures, etc. This approach is able to close an important gap in the characterization of nanoparticles and small structures in the solution as it provides the possibility to study individual nano-objects in the solution-like state with high lateral resolution.
 U. Mansfeld, S. Hoeppener, U.S. Schubert, Adv. Mater. 2013, 25, 761-765.
3:00 AM - *FF2.03
In-Situ TEM Study of Electrochemical Cell: In Terms of Battery, What We Have Learned and Where We Should be Heading
Chongmin Wang 1 Meng Gu 1 Lucas R Parent 1 Patricia Abellan Baeza 1 Xu Wu 1 Suntharampillai Thevuthasan 1 Donald R Baer 1 Ji-Guang Zhang 1 Jun Liu 1 Ilke Arslan 1 Raymond R Unocic 2 Nigel D Browning 1
1Pacific Northwest National Lab Richland USA2Oak Ridge National Laboratory Oak Ridge USAShow Abstract
Since the inception of the concept of nanobattery with a single nanowire, tremendous progress has been made over the last few years on the direct in-situ TEM observation of structural and chemical evolution of materials related to energy storage. This is especially true for the case of anode materials for lithium ion battery. These in-situ TEM work have helped us to gain some insights on dynamic structural and chemical evolution of electrode materials that cannot be captured before. However, the design of the in-situ cell in the previous work, especially, the operating parameter of the cell during the in-situ testing is still far deviated from a real battery operating condition. Much effort is needed on designing of new cells that enable in-situ TEM study of battery under more realistic conditions. In this presentation, we will review, in retrospective and perspective, the overall progress of in-situ TEM study of battery materials, especially focusing on the challenges that related to anode, cathode, and solid electrolyte interface (SEI) for lithium ions battery and beyond, such as sodium ions and magnesium ions as well.
3:30 AM - FF2.04
Visualizing In Situ Electrochemical Deposition and Dendrite Growth with the Nanoaquarium
Nicholas M Schneider 1 Jeung Hun Park 2 3 Joseph M Grogan 1 Suneel Kodambaka 2 Daniel A Steingart 4 Frances M Ross 3 Haim H Bau 1
1University of Pennsylvania Philadelphia USA2University of California - Los Angeles Los Angeles USA3IBM T. J. Watson Research Center Yorktown Heights USA4Princeton University Princeton USAShow Abstract
Battery cycle-life and safety depend critically on the morphological evolution of the electrode-electrolyte interface during charging and discharging. The potentially catastrophic formation of dendrites is one morphological evolution to be avoided. Recent advances in in situ liquid cell electron microscopy allow us to image the evolution of electrochemical deposition and stripping in real time with nanoscale resolution while controlling the current or potential during the process. The information acquired this way permits us to study process physics as a function of process conditions and electrolyte composition to obtain insights into the mechanisms leading to dendrite formation with the aim of devising means to avoid the same. Here we show in situ electron microscopy videos and electrochemical measurements obtained in a test system, the deposition and stripping of copper in an acidified copper sulphate solution. The experiments were carried out using our custom made liquid cell, the nanoaquarium, which is equipped with micropatterned platinum electrodes. These integrated electrodes were connected to a potentiostat to control and record the current and potential as functions of time during galvanostatic deposition. Simultaneously, the interface morphology evolution was imaged at video rate (30 images per second) as a function of current density using a Hitachi H9000 transmission electron microscope operated at 300kV. Correlating the imaging and electrical measurements facilitates synchronization between the morphology and the electrical data. We will describe the interface morphology and growth kinetics as functions of current density and time. We will show how this data can be used to measure the critical current at the transition from uniform growth to dendritic growth, and we characterize the onset of instability in the growth front. We will finally discuss the results within the context of battery cycling.
3:45 AM - FF2.05
Revealing Materials Transformation during Electrochemical Processes in Liquid Electrolytes
Zhiyuan Zeng 1 Kaiyang Niu 1 Wen-I Liang 1 Haimei Zheng 1
1Lawrence Berkeley National Lab Berkeley USAShow Abstract
An understanding of the materials transformation and interfaces in electrochemical processes is critically important for identifying the failure mechanism or improving the lifetime of batteries and other relevant devices. In-situ transmission electron microscopy, which allows for real-time imaging of electrochemical processes in realistic liquid electrolyte environments with high spatial and temporal resolution, has attracted significant attention. Here, we report using an environmental biasing liquid cell operated in a transmission electron microscope to study electrochemical deposition and dissolution of metal dendrites and structural phase transformation during charge cycles in situ. A commercial electrolyte for lithium ion batteries (ethylene carbonate, dimethyl carbonate and LiPF6) was used. Phase transition of gold nanowires due to lithium ion insertion, solid electrolyte interface (SEI) layer formation, deposition and dissolution of lithium dendrites have been observed in real time. The current-voltage curve was recorded simultaneously during the charge cycles. Based on the combined in situ and ex situ studies we discuss novel mechanisms of transformation during charge cycles.
Electron Microscopy (NCEM) of the Lawrence Berkeley National Laboratory, which is supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231. HZ thanks the funding support from U.S. DOE Office of Science Early Career Research Program.
4:30 AM - FF2.06
In-situ TEM Observation on Multiple-Stripe Lithiation Process in Individual SnO2 Nanowires
Scott X. Mao 1 Li Zhong 1 Jianyu Huang 2
1University of Pittsburgh Pittsburgh USA28915 Hampton Ave NE Albuquerque USAShow Abstract
Although lithiation has been investigated extensively by theoretical simulation over a wide range of different electrode materials, there is a lack of experimental evidence and fundamental understanding on the initiation and evolution of lithiation atomically, which hinders our understanding of the fundamental operation mechanisms in a lithium ion battery. In this talk, using in-situ high resolution TEM, we report that the atomic scale lithiation process of a single SnO2 nanowire anode immersed in an ionic liquid electrolyte. We discovered unexpectedly a multiple-stripe and multiple-reaction-front lithiation mechanism that differs completely from the expected core shell lithiation mechanism. More specifically, the lithiation initiated multiple stripes with width of a few nanometers parallel to the (020) plane traversing the entire wires, serving as multiple reaction fronts for later stages of lithiation. Inside the stripes, we identified a high density of dislocations and enlarged inter-planar spacing caused by lithiation.
4:45 AM - FF2.07
High-Temperature In Situ Observation of Crystal Evaporation in LiFePO4 at Atomic Resolution
Sung-Yoon Chung 1 2
1KAIST Daejeon Republic of Korea2Nalphates Wilmington USAShow Abstract
When crystalline particles are dispersed in their matrix, such as a solution or vapor, it is readily observed that particles larger than those of average size grow, accompanying the dissolution of smaller particles into the matrix at the same time. This particle coarsening process has generally been referred to as Ostwald ripening. As the physical properties of crystals significantly vary with their ultimate size and shape, observation and appropriate control of their growth and dissolution behavior during the ripening process have been recognized as important issues in crystallization studies over the past several decades. Recent advances in transmission electron microscopy (TEM) enable atomic-scale imaging in Li intercalation compounds for direct visualization of lattice defects, phase transition, and structural evolution (S.-Y. Chung et al., Angew. Chem. Int. Ed.48, 543 (2009); S.-Y. Chung et al., Adv. Mater.23, 1398 (2011)). In particular, a variety of techniques have been utilized for real-time observations in TEM, providing unexpected and new experimental findings (S.-Y. Chung et al., Nature Phys.5, 68 (2009); S.-Y. Chung et al., Nano Lett.12, 3068 (2012)). Using in situ high-resolution electron microscopy (HREM) with a heating specimen holder, in this study we demonstrate, for the first time, the atomic-level evaporation behavior of LiFePO4 crystals in real time at high temperature (S.-Y. Chung et al., J. Am. Chem. Soc. (in press)). Prior to detailed observation of crystal evaporation, we also investigated the growth behavior of atomically flat low-index surfaces. A systematic comparison with image simulations along with density-functional theory calculations demonstrated that the cations evaporate preferentially over the [PO4]3- oxyanions, accompanying fast charge transfer from the nearest-neighboring Fe and O. The present study thus shows that our combined technique based on high-temperature HREM and systematic image simulations is a powerful tool to understand the dynamic characteristics of crystal growth and evaporation.
5:00 AM - FF2.08
In-situ TEM Observation of Electrochemistry in All-Solid-State Nano-Batteries
Ziying Wang 1 Dhamodaran Santhanagopalan 1 Danna Qian 1 Feng Wang 2 Jason Graetz 2 Juchuan Li 3 Nancy Dudney 3 Shirley Meng 1
1University of California San Diego La Jolla USA2Brookhaven National Lab Upton USA3Oak Ridge National Lab Oak Ridge USAShow Abstract
Observation of electrochemical phenomena at nano-scale in an all-solid-state lithium ion battery is important for understanding of the role of interfaces. High resolution transmission electron microscopy (TEM) coupled with electron energy loss spectroscopy (EELS) is ideal to track lithium ion movement with high spatial resolution. Functional thin film battery prepared by sputtering has been sliced by focused ion beams and mounted on commercial grids to produce nano-batteries. First to establish consistent electrical biasing of nano-batteries, an in-situ FIB biasing method was accomplished followed by ex-situ TEM/EELS investigation. After successful in-situ FIB biasing, samples with suitable thickness are biased in-situ in TEM. We will present lithium ion tracking by EELS in the nano-scale batteries ex situ and in situ and correlate with their electrochemical profiles.
5:15 AM - FF2.09
In-situ Characterization of Single Nanowire Electrochemical Devices
Liqiang Mai 1
1Wuhan University of Technology Wuhan ChinaShow Abstract
Li ion based energy storage devices with high energy density and long-term stability are considered as one of the most suitable candidates applied for consumer electronics and electric vehicles (EV). Nanostructured materials, especially nanowires, have attracted great interests due to a range of advantages in many energy related fields, such as short Li-ion insertion/extraction distance, facile strain relaxation upon electrochemical cycling, enhanced electron transport, and very large surface to volume ratio. Although the electrochemical properties could be improved, the fast capacity fading is still one of the key issues and the intrinsic reasons need be further understood.
To find out the reasons of fast capacity fading, the process was usually studied ex-situ after disassembling the devices. In-situ probing has been increasingly employed in nanotechnology, such as in-situ XRD, NMR or TEM. Here, we reported the single nanowire electrode devices designed as a unique platform for in situ probing the intrinsic reason for electrode capacity fading in Li ion based energy storage devices. In this device, a single vanadium oxide nanowire or single Si/a-Si core/shell nanowire was used as working electrode, and electrical transport of the single nanowire was recorded in situ to detect the evolution of the nanowire during charging and discharging. Along with lithium ion intercalation by shallow discharge, the vanadium oxide nanowire conductance was decreased over 2 orders. The conductance change can be restored to previous scale upon lithium ion deintercalation with shallow charge. However, when the nanowire was deeply discharged, the conductance dropped over 5 orders, indicating that permanent structure change happens when too many lithium ions were intercalated into the vanadium oxide layered structures. Different from vanadium oxide, the conductance of a single Si/a-Si core/shell nanowire monotonously decreased along with the electrochemical test, which agrees with Raman mapping of single Si/a-Si nanowire at different charge/discharge states, indicating permanent structure change after lithium ion insertion and extraction.
We demonstrate that during the electrochemical reaction conductivity of the nanowire electrode decreased, which limits the cycle life of the devices. The intrinsic reason for electrode capacity fading in Li-ion based energy storage devices was concluded, which may push the fundamental limits of the nanowire materials for energy storage applications.
5:30 AM - FF2.10
Fast Electrogravimetric Methods for Investigating Electrode Materials in Electrochemical Conversion Devices: Application to Electrodeposited MnO2 Thin Films
Claude Gabrielli 1 Alain Pailleret 1 Hubert Perrot 1 Carlota Ridruejo 1 Ozlem Sel 1
1LISE, UPMC Paris 6, CNRS Paris FranceShow Abstract
The need for new materials with improved ion transfer properties continues to be one of the main pressing concerns in energy storage materials research. In accompanying this search for optimal materials, appropriate characterization tools to assess key parameters of newly developed materials are required.
This paper will focus on coupling electrochemical impedance spectroscopy (EIS) with fast gravimetric methods (fast quartz crystal microbalance (QCM)) under dynamic regime. This coupling, so called ac-electrogravimetry measures the usual electrochemical impedance, ΔE/ΔI (omega;), and the mass/potential transfer function, Δm/ΔE (omega;), simultaneously.[1-3] The main interests of this coupling are its ability to indicate the contribution of the charged and uncharged species and to separate the anionic, cationic, and free solvent contributions during the electrochemical/chemical processes. These features make the ac-electrogravimetry as an attractive and appropriate tool to investigate transfer/transport phenomena of charged and uncharged species in ion insertion materials.
As a pertinent example, the adaptation of ac-electrogravimetry to evaluate the ion (Li+, Na+hellip;) transfer phenomena in MnO2 based thin films will be discussed. As a functional metal oxide, MnO2 is one of the most attractive inorganic materials because of its physical and (electro)chemical properties, particularly in energy storage. Thin films of MnO2 with Li+ ion intercalated are synthesized by a one-step electrodeposition method and the electrodeposition process is monitored by QCM.[5,6] The resulting LixMnO2 thin films are studied by classical (micro)structural characterization methods. The ion transfer properties (Li+ and Na+ in aqueous and acetonitrile solutions) are investigated by electrochemical quartz crystal microbalance (EQCM) and ac-electrogravimetry. Our primary findings based on the mass/potential transfer function, (Δm/ΔE (omega;)) report that the cations are inserted under their hydrated form and the free solvent molecules participate indirectly in the charge compensation process with different kinetic constants.
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5:45 AM - FF2.11
Pseudocapacitive Phenomena at the Electrode/Electrolyte Interface Investigated by In-Situ Electrochemical Techniques
Mikolaj Meller 1 Krzysztof Fic 1 Grzegorz Lota 1 Elzbieta Frackowiak 1
1Poznan University of Technology Poznan PolandShow Abstract
Activated carbons with well developed surface area and porosity are very interesting materials especially for electrochemical capacitor (EC) applications. Because of the fact that EC charging/discharging process has strictly electrostatic character, electrochemical double layer capacitors are able to be charged and discharged even in a few seconds. Additionally, to achieve good performance and satisfy high power demands it is necessary to exploit materials characterized with great conductivity and very often with tailored porosity which is responsible for preserving excellent charge propagation. However, the capacitance values reported for these electrodes do not exceed 150-180 F/g. Higher capacitance values can be provided from additional faradaic reactions. Unfortunately, their high price completely eliminates them from commercial using.
Very interesting way to increase capacitance is to use electrode materials (activated carbons) which are electrochemically grafted by using different electrolytes. It means that electrolyte can generate particular functional groups on the surface of carbon electrode which are able to reversible redox reactions. It is a great advantage over pseudocapacitance received directly from the pseudocapacitive electrode material (e.g. transition metal oxides, conducting polymers) where the most limiting factors are slow diffusion and penetration of electrolyte. Electrochemical grafting is also much easier and quicker methods than chemical generation of electroactive groups on the electrode material&’s surface (e.g. during synthesis of electrode material), because this process proceeds in the same assembled system as further electrochemical investigation of its performance.
Three electrode cell investigation revealed changes in behaviour of positive and negative electrode when compared with performance of pure sulphuric acid. The origin of positive electrode capacitance changes from typical electrical double layer to faradaic one after grafting process which is in a great accordance with data obtained from cyclic voltammetry and galvanostatic charging/discharging technique. Apart from electrochemical investigation other techniques were used to confirm if the additional pseudocapacitance really comes from already grafted functional groups on the carbom electrode or directly from redox active electrolyte. For that purpose thermogravimmetric analysis conjugated with mass spectrometer was used and gave very promising results. Investigated electrode after grafting process revealed much higher weight loss than ungrafted one because of significant CO gas evacuation which might be related to decomposition of carbonyl groups. Additionally, Raman spectroscopy was used in order to follow the change in the material functional structure and the results will be discussed.
FF3: Poster Session: In-situ and Operand Methods in Catalysis and Energy Storage
Monday PM, December 02, 2013
Hynes, Level 1, Hall B
9:00 AM - FF3.01
In situ TEM Study of Hydrogenation of Mg Films Decorated with Pd Manoparticles
Sang Chul Lee 1 Chia-Jung Chung 1 Ai Leen Koh 2 Bruce Clemens 1 Robert Sinclair 1 2
1Stanford University Stanford USA2Stanford University Stanford USAShow Abstract
It is widely believed that hydrogen is an ideal clean and efficient carrier for storage and transport of energy. In this context storage of hydrogen is one of the key challenges in developing hydrogen economy. One of the most attractive ways for hydrogen storage is using magnesium hydride. Magnesium can absorb hydrogen in atomic form and thereby act as hydrogen "sponges". It gives not only an important safety advantage over the gas and liquid but also high hydrogen uptake (7.6 wt %). Hence, magnesium hydride is a safe, volume-efficient method for hydrogen storage. However, the slow reaction kinetics and high thermodynamic stability hinder practical applications of this material. To enhance the kinetics and modify the thermodynamics of hydrogenation, it is essential to study the hydrogenation process on the atomic scale by using transmission electron microscopy (TEM). In this study, we investigated the hydrogenation of magnesium films decorated with palladium particles at room temperature by using environmental TEM. In addition, the vacuum transfer specimen holder was also used in order to minimize the formation of oxide during sample loading. Samples were exposed to hydrogen at the pressure up to 10 mbar in the ETEM. During the hydrogen exposure, we observed of the formation of magnesium hydride successfully. In electron diffraction mode, the formation of two different hydride phases (β-MgH2 and γ-MgH2) was observed. We believe that this experimental observation leads to the fundamental understanding of the reaction mechanism of a hydrogen gas with magnesium.
9:00 AM - FF3.02
Dynamics of Redox Behavior in SrCoOx Epitaxial Films
Dillon Fong 1 Hubert Renevier 2 Valentina Cantelli 2 Marie-Ingrid Richard 3 4 Chad Folkman 1 Hyoungjeen Jeen 5 Ho Nyung Lee 5
1Argonne National Laboratory Argonne USA2Grenoble INP Grenoble France3Aix-Marseille Universitamp;#233; Marseille France4European Synchrotron Radiation Facility Grenoble France5Oak Ridge National Laboratory Oak Ridge USAShow Abstract
Oxide materials are known to be active in a variety of redox reactions, making them important for many energy technologies. Unfortunately, the complex interactions between such reactions and the structural/chemical evolution of the oxide surface are not well understood. This has hindered progress in many areas, including solid oxide fuel cells, corrosion, and the development of new heterogeneous catalysts. However, with the advent of high precision growth techniques, epitaxial oxide heterostructures can now be synthesized with controlled strain, orientation, and surface termination, thereby allowing model studies of surface behavior. We examine the reactivity of epitaxial SrCoO3-δ thin films using in situ X-ray studies at the synchrotron, focusing on the kinetics of oxidation and reduction in these materials. Both the dynamics of surface reactions and phase transitions are studied, using both incoherent scattering techniques and x-ray photon correlation spectroscopy. We find that oxidation can be characterized by two distinct time constants, and different mechanisms for the spread of oxygen in this material will be discussed.
9:00 AM - FF3.03
High Temperature Environmental Scanning Electron Microscopy of Ni/YSZ Surfaces after Exposure to PH3
Mahfuzur Jony 1 Harry Finklea 1 Mingjia Zhi 2
1West Virginia University Morgantown USA2West Virginia University Morgantown USAShow Abstract