bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Low Cost and High Capacity Synthesis of Lithium Iron Phosphate Using a Pulse Combustion Reactor System
Authors: Krizan Gregor , Dominko Robert , Gaberscek Miran 
Published: February 2020

We have developed a reactor for continuous synthesis of various metal oxide materials in oxidizing or reducing atmosphere. The capacity of the current pilot reactor version is 2 L of precursor per hour. In the case of synthesis of lithium iron phosphate this corresponds to 100 grams per hour and the procedure is scalable to 100 kilograms per hour. The apparatus is comprised of a pulse combustion type burner, which operates at a frequency of 150 – 240 Hz and a temperature above 1000 °C, a two fluid nozzle for spraying the precursors, and a reactor pipe, where the reaction takes place. The oxidizing and reducing atmosphere is controlled by setting a fuel rich or fuel lean burning. When working with reducing atmosphere the spraying gas is nitrogen, otherwise air or oxygen can be used. The particles are cooled down with air to about 150 °C and collected with an electrostatic precipitator.
Here we demonstrate the functioning of the reactor on the example of lithium iron phosphate. The two precursors used consisted of iron nitrate and lithium carbonate, dissolved in nitric acid. The phosphorus source in one case was ammonium dihydrogen phosphate and triethyl phosphate in the other. As the fuel we used either urea combined with sucrose or glycine. All compounds were dissolved in deionized water. When the precursor is heated up, the water evaporates, and the remaining nitrates and organics react. This process is equivalent to solution combustion synthesis. However, changing the composition of the precursor strongly affects the morphology of the produced materials, which means that the reaction in the precursor is as important as the conditions in the reactor.
By spraying such precursors into the hot zone of the reactor, which is held at about 800 °C, the formed droplets are each its own microreactor. The water from the droplets evaporates very fast because of the high temperature and good heat transfer in pulse combustion burners; the temperature in the reactor drops to about 700 °C. This leads to a precipitation of precursor salts and hinders the coalescence of droplets. After the salts reach a high enough temperature, the reaction starts so that a lot of gaseous products are produced. In the case of urea precursor, porous spheres with a diameter of 3 – 15 μm are formed; in the case of glycine precursor agglomerates of particles from 50 to 300 nm are formed. The particles in both cases are carbon coated, either due to carbonization of sucrose or an excess of glycine fuel.
As synthesized lithium iron phosphate is partly amorphous, mainly because of the very short residence time at a temperature above 500 °C. Heat treatment in an Ar atmosphere at 700 °C for 3 hours yielded phase pure lithium iron phosphate. The as prepared and heat treated materials have been investigated using XRD, SEM, CHNS elemental analysis and ICP. The electrochemical behavior of as prepared and thermally treated materials has been investigated in a lithium half cell.
Flash Solution Oxidation in the Preparation of Cathode Materials for Mg and Li Ion Power Sources
Authors: Sutto Thomas Edward 
Published: February 2020

Using a previously described approach towards preparing oxide nanoparticles via the use of potassium superoxide, we have explored the preparation of cathode materials such as LiCoO2, LiMn2O4 or Mg(M1,M2)O2. From solutions of LiI, or Magnesium Acetate with various transition metals, it is possible to prepare a wide host of potential nanopoarticulate cathode materials in solution. Initial preparation typically yields an amorphous blend of the material, but subsequent oxygen annealing at relatively low temperatures (100-200 oC) results in the formation of nanometer sized cathode materials, such as shown in the accompanying figure for 2.5 nM sized LiCoO2 prepared via this solution method.

Figure 1
Lithium-Titanate Thin Films By Solid State Reaction As Electrode Material for Thin-Film Lithium-Ion Batteries
Authors: Labyedh Nouha , Put Brecht , Hardy An , Van Bael Marlies K , Vereecken Philippe M. 
Published: February 2020

Lithium titanate (Li4Ti5O12) or LTO continues to attract great interest as anode for lithium ion because of its safety and the potential high power for the nanoparticle form. Its spinel structure allows a reversible three lithium ions intercalation at 1.55V vs Li+/Li which is well above the potential for the reduction of most electrolytes including solid electrolytes. The high voltage of lithium ion insertion/extraction in/from Li4Ti5O12 also prevents the formation of dendritic lithium which can happen due to overcharging for anodes which have low potentials close lithium deposition (0V vs Li+/Li). Such metallic lithium filaments can cause a short circuit between the battery anode and cathode with potential overheating and rupture. Moreover, LTO shows a negligible volume change during battery charging and discharging. Despite all these advantages, LTO has a poor electronic conductivity that leads to a limitation in the rate capability of this electrode.
In this talk we will report on a novel and low cost fabrication method of lithium titanate thin film electrodes for thin-film lithium ion batteries. The process is based on a solid state reaction occurring between TiO2 and Li2CO3 stacked-layers upon thermal annealing. The TiO2 layer was prepared by thermal oxidation of a sputtered Ti film and the Li2CO3 layer was deposited by spin-coating. LTO thin films were prepared on both Pt and TiN current collectors.
The phase and morphology of the prepared LTO films were investigated using a X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD patterns display intense characteristic diffraction LTO peaks and SEM micrographs show a close and continuous 70 nm thick LTO film.
Furthermore, the stoichiometry of the fabricated LTO films was evaluated by X-ray photoelectron spectroscopy (surface spectra and depth profile analyses) and elastic recoil detection (ERD) analyses. Films with composition the spinel Li4Ti5O12 composition were fabricated, proving that the thermal treatment causes elements intermixing leading to the formation of a Li4Ti5O12 material.

The electrochemical activity of the films was studied by cyclic voltammetry and galvanostatic charge/discharge experiments. The cyclic voltammogram reveals redox peaks around 1.55V (vs. Li+/Li) corresponding to the Li-ion insertion/extraction in/from the spinel Li4Ti5O12 upon reduction/oxidation of Ti4+/Ti3+. The lithiation and delithiation curves show extremely flat plateaus at 1.55 V (vs. Li+/Li) characteristic of Li4Ti5O12. A 100% of the LTO theoretical capacity was reached at 0.1 C. A difference between the lithiation and delithiation capacities at the same C-rate was detected. This discrepancy will be explained by the difference in Li-ion diffusion kinetics during Li-ion insertion and extraction processes.
Efficient Synthesis of Hierarchical Porous Carbons for Application in Li-S Cells
Authors: Strubel Patrick , Thieme Sören , Althues Holger , Kaskel Stefan 
Published: February 2020

The Li-S battery is a promising candidate to meet the demands on future generation mobile power supplies due to the high theoretical gravimetrical energy density and low price of sulfur. Unfortunately, the active material sulfur exhibits a very low conductivity, which limits the performance. A nanostructured carbon matrix is required. Up to date, large numbers of novel, elaborate host structures have been explored. However, in particular, suitable and effective production processes need to be established.
To overcome the existing drawbacks we focus on the development of a scalable and efficient approach for the synthesis of nanostructured porous carbon materials by using of inexpensive, commercially available ZnO nanoparticles as hard template.[1] One major benefit of the process is the in-situ removal of all pore building components through carbothermal reduction. Thus, no toxic/reactive gases are required and purification of the as-prepared porous carbon is not necessary. Adjusting the ZnO-NP template size, porous carbons with internal pore volumes as high as 3.9 cm3 g-1 and tailored pore sizes reaching from 20 nm to 200 nm with ideal template replication are obtained. The carbothermal reduction process, furthermore, facilitates the access of a hierarchical pore system with distinctive microporosity leading to very high specific surface areas even exceeding 3000 m-2 g-1. The synergetic advantage of that bimodal porosity renders them particularly suitable for the application in high energy density lithium-sulfur batteries. A high capacity of > 1200 mAh g-1-sulfur (> 750 mAh g-1-electrode) at a high sulfur loading of ≥ 3 mg cm-2 and good cycle stability was achieved even using a low amount of electrolyte. This allows for further weight reductions and maintenance of high energy density on cell level.
[1] Strubel et al., Adv. Funct. Mater. 2015, 25, 287–297. doi: 10.1002/adfm.201402768.
Solid-State Lithium Polymer Secondary Batteries
Authors: Hogan Matteo , Wilson James , Holder Simon , Browning Darren , Alfredsson Maria 
Published: February 2020

Energy storage plays a vital role in everyday life. As the worlds need for energy has increased so has the demand for better performing batteries, batteries that can defy conventional constraints and batteries that have improved safety. Currently Lithium ion batteries dominates this sector due to their high specific energy and high specific power.
However they are currently not without faults, improving on their design and construction would be greatly beneficial in certain industries. For example, non-metallic batteries could be useful when a reduction in interference with an antennae signal is desired, another possibility is to create a polymer which is both ionic and electrically conducting as this allows the removal of current collectors from a conventional design again reducing interference and also the number of interfaces in the battery construction. In addition to this, polymer electrolytes could offer a viable design solution for when irregularly shaped batteries are necessary and this would also remove the issue of combustible electrolytes. The objectives are to synthesise mixed conducting polymers and electrochemically test them, then assemble a solid-state Lithium polymer battery. Results based on these systems will be presented are the battery cycles giving both individual polymer performance and again with the full solid state assembly.
Thermal Runaway of a Commercial 18650 Li-Ion Battery with a NCA Cathode - Impact of SOC and Overcharge
Authors: Golubkov Andrey , Scheikl Sebastian , Planteu Rene , Voitic Gernot , Thaler Alexander , Hacker Viktor 
Published: February 2020

Li-ion batteries excel in energy density and cycle life. Unfortunately those benefits come with a price: When Li-ion batteries are mistreated with high over-temperature or strong overcharge, they can transit into a so-called thermal runaway(TR). During the TR, exothermic reactions increase the temperature. In turn, the increased temperature accelerates those reactions and the system destabilizes. At the end of the TR, battery temperatures higher than 900°C can be reached and high amounts of burnable and harmful gases are released.
We examined the TR characteristics of a commercially available 18650 cell made by a well known manufacturer. This cell is based on Lix(Ni0.80Co0.15Al0.05)O2cathode and has energy density of 254Wh/kg. Destructive temperature-ramp experiments with discharged, partially charged as well as fully charged and over-charged cells were done. Additionally, we dismantled one cell to make a mass split and to identify the compositions of the cell components.
In the presentation correlations between SOC and the TR parameters (onset temperature, max. temperature, amount of produced vent-gas, vent-gas composition) will be shown. An attempt will be made to rationalise the amount and composition of the vent-gas with a simplified chemical reaction system.
We hope that the results of this work can aid the industry to enhance the safety of battery driven devices and to find appropriate mitigation measures for some of the battery abuse scenarios.

Figure 1
Graphite As Anode Material for Sodium-Ion Batteries: Making an Inactive Electrode Active to Compete with Li-Ion Batteries
Authors: Jache Birte , Adelhelm Philipp 
Published: February 2020

Being the standard anode material in lithium-ion batteries (LIBs), graphite is considered to fail application in sodium-ion batteries (NIBs) because no suitable binary intercalation compounds (b-GICs) exist. In this study, we demonstrate that this limitation can be successfully circumvented by using co-intercalation phenomena in a diglyme-based electrolyte. Results have been published in Angewandte Chemie International Edition: B. Jache, P. Adelhelm, Angew. Chemie
2014, 53, 10169–10173. The resulting compound is a stage-I ternary intercalation compound
(t-GICs) with an estimated stoichiometry of Na(diglyme)2C20.
Beneficial properties of the electrode reaction are its low overpotentials and stable capacities of around 100 mAh/g for more than 1000 cycles. The initial irreversible capacity of around 10 % is, to the best of our knowledge, the smallest one reported so far for NIB negative electrodes. The overall coulomb efficiency exceeds > 99.87 %. The intercalation process proceeds over several intermediated stages and occurs in narrow potential window below 1 V vs. Na/Na+. A one-to-one comparison with the analogue lithium system shows the more suitable performance of the sodium based system. X-ray diffraction was used to study the electrode reaction during different stages of sodiation/lithiation. The reversible formation of ternary GICs is unequivocally proven by the shift in the (002) diffraction line and the appearance of additional reflexes.
The peculiar properties of ternary GICs combined with the advantage of using relatively low cost substances might make this electrode reaction attractive for stationary applications. As t-GICs are also formed with other solvents, our approach provides an alternative route to search for new electrode reactions for NIBs.

Figure 1
Investigating the Effects of Transport and Mixing on Dendrite Growth in High Energy Density Lithium Batteries
Authors: Tan Jinwang , Tartakovsky Alexandre , Ryan Emily M 
Published: February 2020

High Energy density lithium (Li) batteries are promising advanced energy technologies for applications in the automotive and portable power markets. Advanced Li batteries have several design and operational challenges to overcome before becoming commercially viable. One of these challenges is the formation of dendrites on the anode surface of the Li-air battery over multiple charge and discharge cycles. Dendrite formation decreases cell performance and causes safety concerns due to short circuiting. In this research computational methods are adopted to investigate the physics of dendrite formation in Li-air batteries and to develop strategies to suppress dendrite growth.
The effects of convection and anisotropic transport properties in the electrolyte on the morphology and growth rate of dendrites are investigated using a two-dimensional (2D) smoothed particle hydrodynamics (SPH) model. SPH is a mesh-free Lagrangian computational fluid dynamics method, which allows for easy implementation of complex physics at the dendrite surface.
Anisotropic diffusion is modeled to study the effects of mixing near the anode-electrolyte interface on dendrite growth. The simulation results suggest that high anisotropy in the electrolyte promotes a robust, compact dendrite structure versus isotropic diffusion cases. Convection effects are also considered to study the electro-osmosis effect on dendrite growth. Circulating flows are included in the model to simulate electro-osmotic flows near the anode-electrolyte interface. The simulation results reveal that the convection effect will increase the mixing near the dendrite and lead to significant changes in dendrite morphology.
The results of these computational studies are being used to develop mitigation strategies for dendrite growth in Li-air batteries. These strategies include the use of novel electrolyte solutions and hybrid electrolyte designs, which allow for the tuning of transport properties through the electrolyte. The computational models are being used to investigate these designs and optimize material properties to increase battery performance and lifetime.

Figure 1
Finding Stable Solid Electrolyte-Cathode Interfaces for Li7La3Zr2O12 Garnet - a DFT Study
Authors: Miara Lincoln J. , Richards William Davidson , Wang Yan , Ceder Gerbrand 
Published: February 2020

Lithium garnets with the general formula Li7La3Zr2O12 (LLZO) have many properties of an ideal electrolyte in all-solid state lithium batteries. However, internal resistance in batteries utilizing these electrolytes remains high. For widespread adoption, performance must be improved by improving bulk conductivity, reducing grain boundary resistance, and/or pairing LLZO with an appropriate cathode to minimize interfacial resistance.
Despite high bulk conductivity, any electrolyte is impractical if a large interfacial resistance is present, arising either from decomposition products formed between cathode and electrolyte at high sintering temperatures or from electrochemical decomposition at the interface during cycling. The origin of the observed interfacial resistance in all solid state batteries is currently a matter of some debate. There are usually two explanations given in the literatures: the buildup of a space-charge layer at the interface, and interfacial phase-decomposition1–5

In this work we use first principles calculations to identify the thermodynamic driving forces for reactions between the electrolyte and electrode across the lithium chemical potential range experienced during operation. We examine LLZO and the similar material Li5La3Ta2O12(LLTO) against common cathodes. We perform a careful thermodynamic assessment of the interface equilibrium using a grand canonical ensemble. We also provide valuable information when choosing a system for all-solid-state battery construction using LLZO or LLTO as an electrolyte.

References

(1) Takada, K.; Ohta, N.; Zhang, L.; Xu, X.; Hang, B. T.; Ohnishi, T.; Osada, M.; Sasaki, T. Solid State Ionics
2012, 225, 594–597.
(2) Maier, J. Nat. Mater.
2005, 4, 805–815.
(3) Takada, K.; Ohta, N.; Zhang, L.; Fukuda, K.; Sakaguchi, I.; Ma, R.; Osada, M.; Sasaki, T. Solid State Ionics
2008, 179, 1333–1337.
(4) Takada, K. Langmuir
2013, 29, 7538–7541.
(5) Haruyama, J.; Sodeyama, K.; Han, L.; Takada, K.; Tateyama, Y. Chem. Mater.
2014, 26, 4248–4255.
Theory and Modeling of Platinum Surface Reactions
Authors: Baroody Heather , Rinaldo Steven , Eikerling Michael 
Published: February 2020

The formation and reduction of surface oxide species determine both the electrocatalytic activity of Pt towards the oxygen reduction reaction as well as the rate of corrosive Pt dissolution [1]. We perform theory and modeling work to rationalize the various stages of oxide formation and reduction at Pt. Our mechanistic models establish relations between metal phase potential and surface oxidation state that govern the transient current response of the electrode, as probed for instance in cyclic voltammetry. In the first part, we will discuss a recently developed kinetic model for oxide formation and reduction at Pt in the voltage range of 0.65–1.15 V [2]. The model is evaluated against electrochemical [3], spectroscopic [4] and computational studies [5]. In the second part, we will present a kinetic model of oxide growth on platinum in the high voltage regime, above 1.15 V. The governing equations of the oxide growth model account for mass and charge conservation, species migration, and electric field effects. As the outcome, we will obtain a generalized oxide growth law of platinum. The results will be compared to experimental cyclic voltammetry data to extract rates of kinetic and transport processes. Moreover, the model incorporates a mechanism of platinum dissolution. Using this model, we strive to explain the dramatically enhanced rate of Pt dissolution at extended surfaces and in nanoparticle systems, observed in experimental studies that involved voltage cycling through the high voltage regime [6,7,8]. Knowledge of the mechanisms of growth and reduction of oxides on platinum will allow us to refine our theory of platinum dissolution in polymer electrolyte fuel cells [9].

References

[1] A. Seyeux, V. Maurice, and P. Marcus, J. Electrochem. Soc.
160, C189 (2013).
[2] S. G. Rinaldo, W. Lee, J. Stumper, and M. Eikerling, Electrocatalysis
5, 262 (2014).
[3] A.M. Gómez-Marín, J. Clavilier, J.M. Feliu, J. Electroanal. Chem.
688, 360 (2013)
[4] M. Wakisaka, H. Suzuki, S. Mitsui, H. Uchida, M. Watanabe, Langmuir
25, 1897 (2009)
[5] L. Wang, A. Roudgar, M. Eikerling, J. Phys. Chem.
C
113, 17989 (2009)
[6] S. G. Rinaldo, P. Urchaga, J. Hu, W. Lee, J. Stumper, C. Rice, and M. Eikerling, Phys. Chem. Chem. Phys., submitted.
[7] A. A. Topalov, S. Cherevko, A. R. Zeradjanin, J. C. Meier, I. Katsounaros, and K. J. J. Mayrhofer, Chemical Science
5, 631 (2014).
[8] L. Xing, M. A. Hossain, M. Tian, D. Beauchemin, K. T. Adjemian, and G. Jerkiewicz, Electrocatalysis
5, 96 (2014).
[9] S. G. Rinaldo, W. Lee, J. Stumper, and M. Eikerling, Physical Review E
86, 041601 (2012).
Quinone Redox Flow Battery Electrode Testing
Authors: Brezovec Paul , Kennedy Timothy , Markiewicz Daniel , McCluskey Michel 
Published: February 2020

The efficiency and cost of a redox flow battery (RFB) can be significantly affected by the electrode selected for scale-up. Carbon felt has traditionally been used as the electrode in flow batteries, but flow battery design requires it to be highly compressed thereby requiring high pumping power and causing battery leakage problems. Additionally, by compressing the felt, the electrolyte must be pumped through the felt at enough pressure to ensure uniform flow through the felt. Carbon felt has a high specific surface area and good electrical conductivity. Any replacement must meet the needs of the flow battery system in terms of specific surface area and electrical conductivity. Prototype alternatives to the homogeneous carbon felt were screening tested, indicating that configurations of foam and felt composite were useful to lower pressure drop through the cell while providing the necessary electrical continuity for RFB operation.
Quinone electrolytes were employed in each half-cell to test the charge/discharge performance of the RFB. A design of experiment methodology was used for a composite electrode, while varying current and electrolyte flow. Interesting delayed double-electron transfer effects were noted from the redox of the quinone electrolytes. Testing has shown that the composite electrode has advantages over the felt. The testing confirmed that the composite electrode has the potential of increasing the efficiency of the flow battery. Testing results to date will be reported indicating the redox of the quinone electrolytes when the composite electrode configuration is changed.