Description
(18h00-19h30) Poster Session & Finals
(19h30-20h00) Mingle session
In a real-world situation, a battery is not cycled continuously until death nor stored endlessly at top of charge. Test conditions should mimic real-world situations to better understand different failure mechanisms occurring within cells of the same build and electrolyte. Three complimentary tests are proposed to probe cycle-dependent and time-dependent aging under a spectrum of voltage and...
Metallic Li is considered as the promising anodes for next generation Li-metal batteries including Li-S, Li-air and all solid-state batteries. However, it is still a crucial problem of Li dendrite growth and large volume change during the stripping/plating process. In our study, the advanced atomic/molecular layer deposition (ALD/MLD) is used to deposit protective coatings on Li metal with...
Instability of GaAs and AlGaAs in an aqueous environment increases drastically following illumination with photons of energy exceeding bandgap of these materials. We have investigated the dynamics of photon-induced dissolution of GaAs/AlGaAs nano-heterostructures in deionized water (DI H2O) and ammonium hydroxide (NH4OH) environments by employing inductively coupled plasma mass spectrometry...
In the quest for high performance materials for energy storage, a comprehensive toolbox of characterization techniques - both experimental and theoretical - is an absolute necessity. In recent years, many techniques have been increasingly focussed on combining observations of material structure, composition, and dynamics to develop a complete picture on how various material properties affect...
Sometimes lithium-ion cells show a very insidious type of failure where they display close to 100% of their capacity for about 1000 charge-discharge cycles and then lose most of their capacity in only 100 cycles or so with very little warning to the user. This is called “rollover failure”. Experimental observations show that the likelihood of rollover failure increases with upper cutoff...
Lithium Ion Batteries are widely used in a large variety of consumer products. With the rise in use in electric vehicles, increasing the energy density of LIBs is a priority. One way of accomplishing this is to increase the charge cutoff potential. However, this results in significant deterioration of the LIBs caused by side reactions between the electrolyte and the electrode. A possible...
Carbon-based nanomaterials are key components in energy storage devices. Their functions can be tailored by adjusting or developing new synthesis pathways. In this study, two living radical polymerization techniques, an electrochemically-aided atom transfer radical polymerization (e-ATRP) and reversible addition chain transfer polymerization (RAFT), were applied for grafting of carbon...
Nickle-rich LiNixMnyCozO2 (x + y +z = 1) (NMC) (Ni content higher than 60% of the total transition metals) is one of the most promising positive electrode materials for lithium-ion cells due to its high specific capacity of up to 220 mAh/g. Conventional NMC materials such as LiNi0.4Mn0.4Co0.2O2, LiNi0.5Mn0.3Co0.2O2, LiNi0.6Mn0.2Co0.2O2 etc. have more than 20% Co among the transition metal...
Improving the cost, lifetime, and energy density of lithium-ion cells is critical in the transition away from fossil fuels for energy production and transportation. Increasing the operational voltage of a lithium ion cell is one way to increase energy density and decrease cost. However, traditional solvents used in lithium-ion electrolytes are not stable at these potentials, causing what are...
Normal Li-ion cells with a positive electrode and a negative electrode normally have a voltage near 4.0 V. There are many surprising things about lithium-ion cells. One of these is that unwanted chemical reactions between one charged electrode (say the positive) and the electrolyte can create reaction products that migrate to the other electrode (say the negative) and affect it dramatically...
Michael Bauera, Eric Logana, Lauren Thompsonb, J.R. Dahna,b
aDepartment of Physics and Atmospheric Science, Dalhousie University, Halifax B3H 3J5, Canada
bDepartment of Chemistry, Dalhousie University, Halifax B3H 4R2, Canada
Li-ion cells contain liquid electrolyte that degrades over the course of their lifetime. High...
Lithium-ion cells are complex electrochemical system and various physical properties can be measured, giving valuable insights into their behavior, state-of-health, degradation mechanisms, etc.. However, many such insights remain unexploited because of the difficulty of relating the raw data to the variables of interest. This is a setting well suited to Machine Learning. This talk will take as...
The widespread adoption of electric vehicles over gas-powered transport is essential to our sustainable future. Consequently, the lithium-ion batteries used for electric cars are receiving more and more attention. Lithium-ion cells with LiNi0.8Co0.15Al0.05O2 (NCA) positive electrodes have been observed to lose capacity during their lifetime as a result of impedance growth.1,2 Understanding the...
Improving the energy density, cost and lifetime of current lithium-ion batteries is vital for the electric vehicle industry and for grid energy storage. It is known that the composition of the electrolyte solution in lithium-ion batteries can dramatically affect their performance. For that reason, it is common to add a small amount of additives to the electrolyte solution to limit impedance...
Quasi-2D materials are composed of stacks of atomically thin layers. While individual monolayers have unique thermal and electronic properties on their own, quasi-2D materials introduce an array of new characteristics, such as anisotropic transport properties and thickness-dependent properties, which have important applications in optoelectronics and thermoelectrics. Our group is particularly...
More than half of the energy produced worldwide is currently lost as waste heat and recovering a
fraction of the lost energy would have an enormous impact on global climate change. In this sense, thermoelectric materials can convert waste heat to useful electricity. However, because of their
low efficiency, high cost, and use of scarce resources, thermoelectric materials are not...
Fourier Transform Infrared (FTIR) spectroscopic techniques are well established for their ability to identify mixtures of compounds and polymorphs in solid materials. These spectra can be recorded using either optical or acoustic detectors. Transmission FTIR spectroscopy (FTIR-TR) has been used in the past to access crystallinity differences in archaeological and lab-produced calcium carbonate...
Thermoelectric materials can be used to construct solid-state devices that convert excess heat into electrical power. Because roughly half of all energy generated is lost as waste heat, efficient thermoelectric devices represent an opportunity to significantly reduce global energy production. However, predicting whether a material will exhibit efficient thermoelectric conversion is a highly...
With the aid of different polymer materials, intermolecular interactions, energy levels, and optical absorption spectra of polymers and fullerenes can be adjusted so as to enhance the efficiencies of heterogeneous organic solar cells. It is known that computational simulations such as density functional theory (DFT) can play an important role in identifying polymers with favourable properties...
A number of recent calculations and experiments have identified that strain and finite size effects are important contributions that influence the stability of the magnetic textures in MnSi thin films. Both of these effects play an important role in MnSi films grown on Si substrates and have an important influence on the magnetic phase diagram. However, there continues to exist controversy...
The broken inversion symmetry in non-centrosymmetric magnetics produces a chiral interaction responsible for the formation of stable nanoscale magnetic solitons in these materials, known as skyrmions. The inverse tetragonal Heusler alloys possess a D2d point group symmetry that gives rise to antiskyrmions, recently discovered in Mn1.4PtSn [1]. We are investigating the related family of...
Liquid electrolytes are essential to all battery systems, yet little is known of the changes that occur during the lifetime of a cell. It is certain that dramatic changes to the electrolyte of a Li-ion cell occur during operation because sometimes cells opened at the end of life appear “dry” (i.e. no liquid remaining) even though they were filled with substantial liquid electrolyte upon...
Graphite is used as the negative electrode in most Lithium-ion battery chemistries. As demand for Li-ion batteries grows, so does demand for graphite. To help satisfy demand Elcora has acquired a vein graphite mine in Sri Lanka. This talk will discuss the journey graphite takes from the mine to a commercial cell.
Several topics will be discussed. For example:
• Graphite mining...
TiFe is one of the good candidates for the solid-state hydrogen storage. Despite having fast kinetics and fairly good capacity, it’s first hydrogenation is difficult. In this study, we investigated the effect of addition of lanthanum on the hydrogen storage properties of TiFe alloy. As the melting point of lanthanum is much lower than the ones of the other two elements, synthesis by casting...
As lithium ion battery technology expands into more demanding applications such as electric vehicles, attention has shifted away from the conventional LiCoO2 positive electrode material. Instead, nickel-rich materials such as LiNi1-x-yMnxCoyO2 (NMC) and LiNi1-x-yCoxAlyO2 (NCA) have become attractive due to their lower cost, increased lifetime and increased safety.
Coprecipitation is a common...
Redox flow batteries (RFBs), as large scale stationary energy storage systems, have attracted a lot of attention recently as a leading technology to enable integration of renewable energy with the power grid and thereby reduce CO2 emissions caused by the excessive use of fossil fuels. Most work on these systems are primarily based on metal complexes in aqueous electrolytes (limited potential...
Le dioxyde de vanadium (VO2) est un matériau thermochrome de la famille des oxydes de métaux de transition (OMT) qui présente un intérêt scientifique et industriel majeur. En effet, les couches minces de VO2 sont des semi-conducteurs transparents dans la région infrarouge (IR) à température ambiante et passent à un état métallique hautement réfléchissant autour de la température de transition...
In a colloid-polymer mixture, non-adsorbing polymer controls the magnitude as well as the range of the interaction between the colloidal particles. In such a system, a network forming gel phase can be observed due to the adsorption of polymer on micrometer-sized colloidal particles. With tunable interactions, such systems could also be used for qualitative studies of phase transition...
