Prof. Ogumi is one the leading pioneers of lithium-ion technology in Japan and worldwide. His research studies on battery materials include LiCoO2, graphite, and highly oriented pyrolytic graphite (HOPG), Much of his research involved in situ techniques that utilized X-ray, Raman spectroscopy and atomic force spectroscopy (AFM) to investigate the SEI (passivation layer) and lithium intercalation in graphite and HOPG in propylene carbonate (PC)- and ethylene carbonate (EC)-based electrolytes. In this presentation, we will show data and video movies that were obtained during studies of lithium-ion and solid-state batteries using various In operando studies and in situ techniques involving scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction and ultraviolet-visible absorption spectroscopy (UV-vis). These in situ studies are helpful to understand the mechanisms for volume expansion of anodes consisting of lithium metal (20 %), graphite (10 %) and LTO (0 %). Another example that will be discussed is the dimensional changes of the anode, cathode and electrolyte that occur during charge/discharge. The mechanism of lithium dendrite formation was also studied, and details will be discussed in this presentation. [Don’t know what is meant by Bleand and deleted because I‘m not sure it is needed.] Lithium/solid polymer electrolyte (SPE)/sulfur cells were studied by two in situ techniques: SEM and UV-vis. During the operation of the cell, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte. A clear micrograph was obtained of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness during cycling confirmed the failure mechanism; the capacity decays by reducing the amount of active material, which contributes to a charge inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive UV-vis also shows the characteristic absorption peaks that evolve with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S4 2- and of S6 2- during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.

Journal Article Direct and Indirect Observation of Lithium in a Scanning Electron Microscope; Not Only on Pure Li! Get access P Hovington, P Hovington Hydro-Quebec Reaserch Institute, Varennes, Quebec, Canada Search for other works by this author on: Oxford Academic Google Scholar M Lagace, M Lagace Hydro-Quebec Reaserch Institute, Varennes, Quebec, Canada Search for other works by this author on: Oxford Academic Google Scholar E Principe, E Principe Tescan-Orsay Holding, USA Search for other works by this author on: Oxford Academic Google Scholar S Burgess, S Burgess Oxford Instruments NanoAnalysis, High Wycombe UK Search for other works by this author on: Oxford Academic Google Scholar A Guerfi, A Guerfi Hydro-Quebec Reaserch Institute, Varennes, Quebec, Canada Search for other works by this author on: Oxford Academic Google Scholar H Demers, H Demers Department of Mining and Materials Engineering, McGill University, Montreal, Quebec, Canada Search for other works by this author on: Oxford Academic Google Scholar R Gauvin, R Gauvin Department of Mining and Materials Engineering, McGill University, Montreal, Quebec, Canada Search for other works by this author on: Oxford Academic Google Scholar K Zaghib K Zaghib Hydro-Quebec Reaserch Institute, Varennes, Quebec, Canada Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 21, Issue S3, 1 August 2015, Pages 2357–2358, https://doi.org/10.1017/S1431927615012568 Published: 23 September 2015

Novel lithium metal polymer solid state batteries with nano C-LiFePO4 and nano Li1.2V3O8 counter-electrodes (average particle size 200 nm) were studied for the first time by in situ SEM and impedance during cycling. The kinetics of Li-motion during cycling is analyzed self-consistently together with the electrochemical properties. We show that the cycling life of the nano Li1.2V3O8 is limited by the dissolution of the vanadium in the electrolyte, which explains the choice of nano C-LiFePO4 (1300 cycles at 100% DOD): with this olivine, no dissolution is observed. In combination with lithium metal, at high loading and with a stable SEI an ultrahigh energy density battery was thus newly developed in our laboratory.

Knowing the grain geometry in grinding wheels is an asset for better understanding the grinding processes. This study investigates the grain protrusion and rake angles of two self-dressing zirconia-alumina grinding wheels in a robotic grinding process. The topography of the wheel is measured using a confocal scanning laser microscope. An optical image of the surface is used to create a mask of the grains with image processing techniques. Grain geometry information is then obtained by applying the mask to the entire surface. A vertex normal technique is used to find the cutting edges facing the cutting direction and only consider those edges in grain rake angle calculations. Surface parameters, including grain density, width, protrusion height, and rake angle, are extracted from the topography. The grinding wheel is characterized in low, medium, and high depths of cut in the range of robot operation. Results indicate that grain density, width, and protrusion height distribution are not affected by the depth of cut. It is also found that in shallow grinding, grain rake angle shifts slightly to higher negative angles; whereas, with a higher depth of cut, sharper edges exist on the wheel surface, which improve process efficiency.

In situ and ex situ scanning electron microscopy of nano Si and SiO anode particles was carried out during the first cycles, and at various stages of charge. The particle size effects were explored in the range 0.1-20 mu m, providing a new insight into the micro-structural evolution of the particles as a function of their size, and into the 'mechanical' resistance upon important volume change upon phase transformation of these anodes. For small particles, the failure of the battery comes from an electrochemical sintering that compacts the whole electrode, which results in its cracking. The particles keep their integrity when the discharge is stopped at a voltage 0.1 V, which corresponds to the chemical composition Li12Si7, while the particles are known to crack at deeper discharge up to Li22Si5. Replacing the Si particles by SiO particles in an attempt to avoid these structural effects did not help, because of the different chemical reactions during cycling, with the loss of oxygen. (C) 2013 Elsevier B.V. All rights reserved.

This review aims to explore the literature investigating balance outcomes in survivors of childhood cancer. A structured search of five databases resulted in 16 articles included in this review. Nearly all were classified as Level 4 evidence using the updated Oxford Centre for Evidence-Based Medicine Levels of Evidence. Balance abilities have been investigated solely in survivors of acute lymphoblastic leukaemia or central nervous system tumours. The literature tends to support the idea that survivors present with balance difficulties but the results need to be closely scrutinised. Several studies report results using the same experimental group, while other studies use balance outcome measures that have not had their psychometric properties assessed with this population. There are also few studies that evaluate dynamic balance abilities in survivors of paediatric cancers, which may be more influential on functional tasks. Furthermore, very few of the included studies investigate how the found balance deficits affect this population's daily lives, which would be necessary in order to determine if intervention should be geared towards this area. Directions for future research should also include multi-centred, clinically oriented trials to evaluate balance abilities in survivors of childhood cancers compared with healthy control subjects in order to strengthen the literature.

Introduction: Silicon is an attractive anode material due to its high gravimetric and volumetric capacity density of 4200 mAh/g and 9800 mAh/mL, respectively, when the Li4.4Si phase is formed. In spite of this advantage, Si-based anodes show numerous problems that limits their use in commercial in Li-ion batteries. A significant capacity fade occurs during cycling, and low coulombic efficiency is obtained. The performance degrades during the first few cycles due to the large volume change from alloying/de-alloying (chargedischarge) that induces cracks in the micro-size particles and then a failure of electrical contacts. To reduce this effect, we have selected carboncoated SiOx mixed with graphite, nano structured Si particles and carbon-coated nano Si. The characteristic features of SiOx electrodes are they exhibit less volume change than Si during chargedischarge cycling. Lithium metal is very attractive anode material because it does not require a binder, is an electronic conductor and current collector. The aim of this paper is to present the results on the effect of new binders and carbon additives on the electrochemical performance of carbon-coated nano Si and carbon-coated SiOx-graphite electrodes compared to lithium metal electrodes. The morphology changes to nano Si, carbon-coated nano Si and C-SiOx particles using in situ and ex situ scanning electron microscopy will be presented The physicochemical properties and the electrochemical performance of active materials are intimately connected, therefore both must be considered in selecting an alternative material to graphite in negative electrodes for Li-ion batteries. An analysis of this relationship is discussed in this paper. Results: The charge-discharge potential curves at C/24 for C-SiOx-graphite electrodes are shown in Fig. 1. The reversible capacity with SiOx-graphite is 980 mAh/g), but the columbic efficiency is only about 84%. The presence of graphite decreases the capacity and increases the conductivity of the electrode. The capacity of the SiOx-graphite also accounts for the weight of graphite; consequently a lower capacity is expected. Six electrodes at different voltage (Fig. 1) were analyzed. The irreversible capacity loss is due to the formation of the SEI layer on carbon-coated SiOx and graphite surfaces, and the formation of Li2O is evident from EDX and SEM analyses.

Negative electrodes containing SiOx were investigated as alternative negative electrodes to carbon for Li-ion batteries. The results obtained on the effect of binders and carbon additives on the electrochemical performance (i.e., reversible capacity, coulombic efficiency, charge–discharge rate capability) of the SiOx–graphite electrode and SiOx electrode are presented. SEM analysis that utilizes facilities for in situ and ex situ studies were applied to better understand the performance and cycle life of the SiOx-based electrodes. The SEM analysis clearly showed that the SiOx particles expand and contract during charge–discharge cycling, and that some of the particles undergo mechanical degradation during this process. The SiOx–graphite electrode with polyimide binder exhibited a stable capacity of 600mAhg−1 during high-rate charge–discharge from C/4 to 1C. These results suggest that the use of a flexible binder like polyimide and reasonably small SiOx particles (nano-particles) facilitates improved cycle life and higher rate capability.

LiFePO4 (LFP) particles were obtained by grinding ingot synthesized in the molten state. This process, followed by jet milling, and then wet milling, provides a simple way to obtain powders with controlled particle size in the range from macroscopic to 25nm. However, at this time, we find that these particles tend to agglomerate to form secondary particles of size ∼100nm. The particles obtained by this process are characterized by X-ray diffraction (XRD). In situ and ex situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of milling was also investigated by analysis of physical properties using infrared spectroscopy (FTIR) and magnetic measurements. The electrochemical performance was evaluated in cells containing Li/1M LiPF6 in EC:DEC (1:1)/C-LiFePO4. After carbon coating, the LFP particles which are free of impurities, exhibit high-rate capability. Even with a limited amount of carbon (2wt.%) appropriate for commercial batteries, the capacity is 157mAhg−1 at 0.1C, 120mAhg−1 at 10C, without capacity fading after 60 cycles.

The formation of intermetallic compounds (IMC) and its effects at the interface between different metals has always been of interest for the electronics industry, contacts manufacturers and users. The purpose of this work is primarily to develop an in situ technique of thermally aging metallic samples within the vacuum chamber of a scanning electron microscope (SEM). This setup enables ongoing observation of the formation and growth of intermetallic compounds within the chamber. Due to the amount of data available in literature, copper-tin specimens were chosen as a basis to validate the technique. Once the samples were thermally aged, energy dispersive X-ray (EDX) analyses as well as electron backscattered diffraction (EBSD) were done on the surfaces. Ex situ nano-indentation measurements were also performed on the IMC. Results have shown that the IMC formation can be observed while aging within a SEM chamber.

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Zr–2.5Nb pressure tubes used in CANDU (CANada Deuterium Uranium) reactors have a very complex microstructure, with two major crystallographic phases, α and β. These phases include a fair amount of deformation from the extrusion process and the cold working (∼25%) performed at the end of the manufacturing process. This microstructure (texture, grain aspect ratio, etc.) changes along the tube’s length and differs from tube to tube. In order to better understand the deformation mechanisms, these microstructural differences must be statistically characterized. Scanning electron microscopy combined with direct image analysis or with electron backscattered diffraction (EBSD) are good techniques for carrying out such a measurement. However it is not possible, using specimen preparation methods specific for each of these techniques, to reveal all of the grain and phase boundaries. We have thus developed post-treatment algorithms to be able to partially analyze the revealed Zr–2.5Nb microstructure. The first algorithm was used for image analysis treatments of micrographs taken at 5kV on the radial–tangential plane of etched samples using a reactive ion etch (RIE, CF4+O2). The second was developed for EBSD grain mapping and can be used to characterize α-Zr grain shape and orientation. The two techniques are complementary: EBSD gives information about the micro-texture and the relationship between the microstructure and micro-texture while image analyses of SEM micrographs reveal the direction and distribution of the α-Zr lamellae more easily and over a greater sample area than EBSD. However, the SEM micrographs that were used did not reveal any grain boundary (only phase boundary). An analysis of EBSD grain maps reveals that the average α-Zr grain size, mainly in the elongated direction (tangential), is smaller than what is normally obtained from an image analysis of SEM micrographs. The grain size distribution of type I α-Zr grains (deformed original (prior) α-Zr) and type II (stress-induced β-Zr→α-Zr phase transformation) is also shown to be different for sizes greater than 0.4μm2.

Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO4 cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is ≥40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO4 is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO4 cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155mAhg−1 at C/12 is obtained with cells having at least some organic electrolyte compared to only 124mAhg−1 with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO4//Li4Ti5O12 with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2C rate. This study indicates that safety and electrochemical performance of the Li-ion battery can be improved by using mixed IL and organic solvents.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Pressure tubes holding the uranium rods of a CANDU (CANada Deuterium Uranium) reactor show deformation with time in service. At a certain point, this deformation becomes too severe and the tubes must be decommissioned. This reduces the reactor’s energy output. It has been observed that the microstructure of the pressure tubes is indicative of creep behavior. This paper presents the image analysis procedure used to characterize the level of anisotropy and the α-phase dimension of the Zr-2.5Nb alloy used in pressure tubes. The techniques used to evaluate experimental error and to correct for sampling bias are also explained.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008