bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrinsic Degradation Variability in Commercial Lithium-Ion Batteries
Authors: Devie Arnaud , Dubarry Matthieu , Liaw Bor Yann
Published: February 2020

Lithium-ion batteries have first been introduced to market for consumer electronics applications where safety and reliability requirements are less stringent than in industrial applications. 18650-format cells in particular have encountered great success in the laptop industry and the manufacturing processes have matured to the point where 18650 cells found their way into new markets such as personal transportation or energy storage systems. Because 18650 cells are a commodity, they face typical manufacturing process variability which can be an issue with these larger scale battery systems. Indeed, where a laptop battery consists of 2 to 4 cells in series, the battery found in a passenger vehicle such as the Tesla Model S can consist of a series cells count in excess of 100. When taking into account the need for long-term reliable operation of the battery pack and the cost burden associated with premature battery pack failure, it seems critical to ensure long-term performance of the battery pack. Unfortunately, a battery pack is usually as weak as its weakest cells.

Battery pack’s early-life performance and reliability are usually attained by sorting and matching cells used in a battery pack. This mitigation technique has its limits though as it cannot account for the long-term degradation spread of the individual cells composing the battery pack. This degradation spread within a battery pack can have various origins. One of them can be the temperature gradient resulting from the spatial distribution of cells within the pack and the inhomogeneous cooling architecture. Another one can be the intrinsic variations between individual cells toward degradation sensitivity. These intrinsic variations have been documented in a few studies [1-2] but authors did not offer an elucidation of the underlying mechanism. In this presentation, we explore the nature and quantify the extent of the degradation discrepancies within a batch of commercial lithium-ion cells.

Results will be presented that distinguish performance mismatch down-the-road between kinetic origins (internal resistance build-up, degraded rate capability) and thermodynamic origins (loss of lithium inventory, loss of active material). In a limited previous study [3], we established a qualitative correlation between thermodynamic changes and kinetic properties of cycle-aged cells. In this more comprehensive study, we cycle-aged a larger number of single cells for more than 1,000 cycles to derive statistical correlations between these dual aspects of battery degradation.

Figure 1: Evolution of 15 cells capacities.

Returned capacity spread became very significant with cycling

References:

[1] Baumhöfer, T.; Brühl, M.; Rothgang, S. & Sauer, D. U., Journal of Power Sources , 2014, 247, p. 332

[2] Eom, S.W.; Kim, M.K.; Kim, I.J.; Moon, S.I.; Sun, Y.K. & Kim, H.S., Journal of Power Sources , 2007, 174, p. 954

[3] Devie, A.; Dubarry, M. & Liaw, B.Y., 224th ECS Meeting, Orlando, 2014

Figure 1
Ionic Liquid Based Electrolytes for High Temperature Lithium-Ion Batteries
Authors: Plylahan Nareerat , Kerner Manfred , Lim Du Hyun , Johansson Patrik
Published: February 2020

Lithium-ion batteries (LIBs) have primarily been developed for application in portable devices, but during the past decade much attention has been paid on making progress also for electric vehicles (EVs). With this aim, elevated/high temperature (HT) operation and life-length is a critical issue, but HT is also an opportunity for simplified cooling systems (working at ca. 80-110ºC) and faster charge/discharge possible. Conventional organic electrolytes such as LiPF6 in EC:DEC is not a safe option due to high volatility and flammability, ultimately leading to the ease of catching fire, dangerous fumes, and possibly also explosions. Ionic liquid (IL) based electrolytes, on the other hand, are an interesting alternative for HT-LIBs owing to negligible vapor pressures, non-flammability, and high ionic conductivities.

In this work, we demonstrate that the IL Pyr13TFSI with an addition of LiTFSI is a potential electrolyte family for HT-LIBs. These electrolytes possess high thermal stability, up to 350°C, wide electrochemical stability windows, 0-5 V vs Li+/Li°, and ionic conductivities of the order of 10-3 S cm-1 at RT and 10-2 S cm-1 at HT (above 80°C). The LiTFSI0.2Pyr13TFSI0.8 electrolyte shows promising electrochemical stability in a LFP half-cell at 80°C delivering an average discharge capacity of 145 mAh g-1 at 1C (Fig.1). Additional doping of the IL based electrolytes with cyclic carbonates such as propylene carbonate (PC) and/or vinylene carbonate (VC), creating hybrid electrolytes, further improves the cycling performance in terms of capacity, stability and Coulombic efficiency. This is attributed mainly to a decrease in viscosity, leading to higher ionic conductivities and a better wetting of the electrode, and VC has the additional advantage of forming a stable SEI.

High Temperature Lithium-ion Batteries is a project funded by the Swedish Energy Agency and the collaboration between Chalmers University of Technology, Lund University, Uppsala University and Scania CV AB was created within the Swedish Hybrid Vehicle Centre.

Fig. 1 Specific capacity of LFP half-cells using IL based electrolytes cycled between 2.5 to 4.2 V vs Li+/Li° at 80°C and 1C rate. The open and closed circles represent the charge and discharge capacities, respectively.

Figure 1
Aluminium Rods As Current Collectors and Electrodes for 3D Li-Ion Micro-Batteries
Authors: Oltean Gabriel , Nyholm Leif , Edström Kristina
Published: February 2020

The microelectronics industry has advanced at a rapid pace in the last decade. Further advancements are hampered by the lack of suitable on-board power devices. Although Li-ion batteries are the primary choice for energy storage, they cannot store enough energy per foot-print area without compromising power capability. Three-dimensional Li-ion batteries could offer the solution by using all three dimensions for efficient energy storage on a relatively small foot-print area.

Aluminium rods were obtained by template assisted galvanostatic deposition of aluminium into the pores of a commercial membrane. By the subsequent chemical dissolution of the membrane, free standing arrays of aluminium rods deposited on an aluminium substrate were obtained. It was shown that the use of a nucleation pulse prior to deposition led to a homogeneous deposition of aluminium rods, while the use of pulsed current rather than constant current resulted in a narrower distribution of the rods heights [1].

Aluminium is used as a current collector in Li-ion batteries. The deposition of TiO2 onto the aluminium rods was done by means of electrophoresis and a sol-gel derived impregnation method. While the electrophoretic deposition resulted in non-conformal coated rods, the impregnation method gave a thin amorphous deposit which could be cycled against lithium [2].

Finally, aluminium can be used as a negative active material, as it alloys with lithium. A study of the alloying and dealloying of lithium and aluminium was done on the 3D aluminium rods and a model for the lithiation and delithiation of aluminium has been proposed [3]. The aluminium rods were used as a negative electrode in a Li-ion battery against LiFePO4 coated on carbon foam positive electrode in a 3D cell with different geometries of the two electrodes [4].

References:

[1] G. Oltean, L. Nyholm, K. Edström, Electrochim. Acta, 56 (2011) 3203.

[2] G. Oltean, M. Valvo, L. Nyholm, K. Edström, Thin Solid Films, 562 (2014) 63.

[3] G. Oltean, C.-W. Tai, K. Edström, L. Nyholm, J. Power Sources, 269 (2014) 266.

[4] G. Oltean, H.D. Asfaw, L. Nyholm, K. Edström, ECS Electrochem. Lett, 3 (2014) A54.
Organic Vs. Inorganic Cations of Alkali-Metal Halide Containing Ionic Liquids for Sodium-Ion Battery Applications
Authors: Tucker Telpriore Gregory , Angell Charles Austen
Published: February 2020

The power generation from either fossil fuels or preferably renewable energy sources is on the rise throughout the world.  The pursuit of electrochemical devices for energy storage during peak power grid utilization is viable.  There is great interest in further developing sodium batteries, particularly ZEBRA-type cells with chloroaluminate electrolytes.  This lab has worked on understanding of weak-field, low-melting metal-halide based ionic liquids for use in the sodium-ion conducting batteries at a low-temperature of operation.  This undertaking employed both organic and inorganic cations of low charge density, including the much-studied dialkylimidazolium cation.  The vital issue of decreased ionic conductivity caused by alkali ion-trapping in these electrolytes, long known as a qualitative effect was recently quantified, discussed, and reported by us.  We have since compared the conductivities of binary bromoaluminates in which large inorganic cations PBr4
+ formed by a bromide transfer process were used to replace the former dialkylimidazolium cation and here show the differences in the figure below.  Currently, the electrochemical (along with other physical) properties are being characterized in preparations for testing in ZEBRA-type cells.  This study leads to improved understanding of the factors determining electrolyte and electrochemical performance of sodium-containing binary electrolytes over a range of temperatures.  

Figure:  The top set of three conductivity isotherms are for [EMIM]AlCl4 - NaAlCl4 solutions, and the bottom set of three are for PBr4Al2Br7 - NaAl2Br7 solutions of varying molar fractions.  The completely inorganic electrolyte requires 100oC (top blue line isotherm) to attain the ionic conductivity of the electrolyte containing the organic cation at 60oC (mid black line isotherm).  We attribute the difference to incomplete bromide transfer in the formation of the large inorganic cation of the second system.  The “alkali cation-trapping” effect probably remains in effect.

Figure 1
Fast Charging of Li-Ion Batteries in Extreme Cold
Authors: Wang Chao-Yang , Zhang Guangsheng , Ge Shanhai , Xu Terrence , Ji Yan , Yang Xiao-Guang
Published: February 2020

Fast charging is an enabling technology for electric vehicles (EV). Unfortunately lithium-ion batteries are notoriously incapable of fast charging at subzero temperatures,1-3 thereby hindering EVs from dependable and convenient operation under all weather conditions. In this work we describe a novel battery structure, called all-climate battery (ACB), which adds a resistor sheet inside the electrochemical cell to modulate the cell’s internal resistance according to temperature. Based on ACB technology, we have built 12Ah pouch cells using graphite anode, NMC cathode and 1M LiPF6 in EC:EMC (3:7 by wt) + 2% VC and showed that such ACB cells are able to be charged from 20% to 90% state of charge (SOC) in -30oC environment in ~22 minutes, while keeping the cell voltage never exceeding 4.2V (a necessary condition to avoid Li plating).

Figure 1 displays the experimental results of fast charging a 12Ah ACB cell from -30oC with a charge protocol of CV (4.2V) and limited by CC (3C or 36A). It is seen that the charge current under 4.2V charge voltage starts only at ~7A; however, it rapidly increases to 36A (3C limit) in around 400 seconds. Simultaneously the cell outer surface temperature increases from the initial temperature of -30oC to above the freezing point. Thereafter, the ACB cell undergoes 3C constant current charging with the cell voltage dips below 4.2V between 400 and 1100 seconds. During this period, the cell SOC rapidly increases from the initial SOC of 20%, eventually reaching 90% in ~22 min. Figure 2 compares two charge experiments under the same charge protocols of a 12Ah ACB cell and its baseline cell without ACB technology. It is clearly shown that ACB technology has dramatically improved the fast charge capability of Li-ion batteries.

More efforts are ongoing to accelerate the fast charge process from subzero temperatures and to further reduce the charge time from 22 min to within 15 min. These advanced improvements will be elaborated in this presentation. 

References:

1. S. S. Zhang, K. Xu, and T. R. Jow, Electrochem. Commun., 4, 928 (2002).

2. M. C. Smart, J. F. Whitacre, B. V. Ratnakumar, and K. Amine, J. Power Sources, 168, 501 (2007).

3. Y. Ji, Y. Zhang, and C.-Y. Wang, J. Electrochem. Soc., 160, A636 (2013).
Synthesis and Characterization of High Capacity LiFeBO3
Authors: Cambaz Musa Ali , Munnangi Anji Reddy , Pohl Alexander , Witte Ralf , Fichtner Maximilian
Published: February 2020

Polyanionic framework compounds have attracted increasing interest since the first report of LiFePO4 as cathode material.[1] In between these polyanionic compounds the group of the borates are offering attractive features in term of high theoretical capacity. The BO3
3- is having the lowest-weight framework and therefore having the highest theoretical capacity for one electron transfer. It’s having a favourable element combination in terms of toxicity, cost and sustainability. In this work we show how highly pure and high capacity LiFeBO3 can be prepared in a straightforward and effective manner. [2]

The LiFeBO3 samples were synthesized by a simple solid state reaction assisted by high energy ball milling .The refined XRD pattern is shown in Figure 1. The particle size of the material is ranging from 40 – 250 nm. Figure 2 is showing the charge-discharge voltage profile with reversible capacity of around 176 mAhg-1 at C/20 rate within 1,5-4,5V involving Fe3+/2+ redox potential of 2.8 V vs Li0/Li+. Figure 3 is showing the cycling stability and a c-rate test. In addition to that ex-situ characterization of charged and charged-discharged state LiFeBO3 with TEM, XRD and Mössbauer measurements have been performed and will be presented and discussed.

References

1       A. K. Padhi, K. S. Nanjundaswamy, J. B. Goodenough and goodenough, J. Electrochem. Soc., 1997, 144, 1188–1194.

2       A. Yamada, N. Lwane, Y. Harada, S. I. Nishimura, Y. Koyama and L. Tanaka, Adv. Mater., 2010, 22, 3583–3587.

Figure 1
Lithium-Sulfur Battery Cathodes with in Situ Polymerized Conductive Polymer Coating
Authors: Ansari Younes , Chiang Yet-Ming
Published: February 2020

The development of alternative strategies for rechargeable batteries is essential if energy technologies that can displace fossil fuels are to be successful. Among various types of rechargeable batteries, the lithium-sulfur battery is a striking candidate owing to its remarkable theoretical capacity of 1672 mA h/g and theoretical specific energy of 2600 W h/kg. In addition, elemental sulfur is environmentally friendly, inexpensive and abundant.

However, lithium-sulfur battery systems containing organic electrolytes show low cycle life due to the fact that sulfur is electronically and ionically insulating. This causes poor electrochemical accessibility and low utilization of sulfur in the electrode. In addition, generation of soluble intermediate lithium polysulfides during discharge causes an irreversible loss of sulfur-active materials during cycling via the shuttle mechanism. Such problems significantly reduce the cycle life of current lithium sulfur batteries.

We describe in this work the performance of novel cathode materials for lithium-sulfur batteries that utilize coatings of the electronically and ionically conductive polymer polythiophene.  Composite cathodes are synthesized by in situ chemical oxidative polymerization using the well-known Sugimoto–Yoshino method [1]. The conductive polythiophene functions as a conducting additive and as a porous adsorbing agent in the cathode. The PT-coated composites are found to be electrochemically stable within the range of 1.0 - 3.0V versus Li+/Li0,the operating voltage range of lithium-sulfur batteries.

A cyclic voltammogram of a cell using the PT-coated composite as the active cathode material, measured at scan rate of 1 mV s-1, is shown in Figure 1. The reduction peak around 2.4 V corresponds to the transformation of sulfur to high-order lithium polysulfides. Reduction of high-order polysulfides to low-order polysulfides and eventually Li2S shows another peak about 1.9 V. The oxidation peak near 2.6 V corresponds to the transformation to lithium polysulfides (Li2Sn, n>2). The function of the PT-coated composite cathodes, their cyclic durability, and their rate capabilities will be compared with conventional cathode materials.

Acknowledgement:This work is supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

Figure 1: Cyclic Voltammogram of a polymer coated carbon-sulfur active cathode material. Voltammogram is obtained at 1.0 mV s−1. Inset shows the cathode powder with C/S ratio of 1/2  before (Left) and after (right) polythiophene coating.

Reference 1) Yoshino, K.; Hayashi, S.; Sugimoto, R. Jpn. J. Appl. Phys. 1984, 23, L89.

Figure 1
Improved RhxSy/C Catalyst Structure for Higher HOR/HER Activity
Authors: Li Yuanchao , Nguyen Trung Van
Published: February 2020

With the development of distributed energy resources such as wind and solar power, there has been growing interest in electrical energy storage. The hydrogen-bromine (H2-Br2) reversible fuel cell system serves as one of the promising technologies because of its high round-trip conversion efficiency and low cost. For the highly corrosive HBr/Br2 environment, alternative catalysts to platinum, which was shown to be rapidly corroded and poisoned in this environment, is needed for the HER/HOR reactions at the hydrogen electrode. RhxSy catalysts have been found to be stable in the HBr/Br2 environment. Even though existing RhxSy catalysts show high specific HER activity, which makes these catalysts suitable for HBr or HCl electrolysis, their specific HOR activities are not satisfactory for the H2-Br2reversible fuel cell system [1, 2]. Recently, we have found a way to develop an optimal RhxSy catalyst structure that results in higher specific HER/HOR activity, as shown in Figure 1. This presentation will discuss the approach used and the characteristics and performance of this catalyst.

References

J. Masud, T.V. Nguyen, N. Singh, E. McFarland, M. Ikenberry, K. Hohn, C.J. Pan, and B.J. Hwang, J. Electrochem. Soc., 162 (4) F455-F462 (2015).

A. Ivanovskaya, N. Singh, R.F. Liu, H. Kreutzer, J. Baltrusaitis, T.V. Nguyen, H. Metiu, and E. McFarland, Langmuir,
29
, 480-492 (2013).

Acknowledgements

The work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000262 and the National Science Foundation under Grant No. EFRI-1038234.

Figure 1
Manganese Dioxide Polymorphs As Oxygen Reduction Catalysts
Authors: Donne Scott W , Pulukadang Sri
Published: February 2020

Oxygen, a chemically reactive element, is consumed during the oxygen reduction reaction (ORR) via a cathodic reduction process in almost all fuel cell systems. Electrochemical reactions involving oxygen are kinetically slow, therefore, electrocatalysts are needed to increase the rate of this reaction. The ORR activity of electrodeposited manganese dioxide, as well as different powdered polymorphs of MnO2 (α-MnO2; β-MnO2; γ- MnO2 ; δ-MnO2; λ- MnO2) has been investigated using a glassy carbon substrate.  Dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and acetonitrile (ACN) with tetraethyl ammonium tetra fluoroborate was used as a supporting electrolyte to assess activity using rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements. The results and the effects of different polymorphs will be described and discussed. Overall, the polymorphs of MnO2 catalysts exhibit good catalytic activity.
Analytical Modeling of Thermal Conductivity of Catalyst Layer of Polymer Electrolyte Membrane (PEM) Fuel Cells
Authors: Ahadi Mohammad , Stumper Jüergen , Bahrami Majid
Published: February 2020

In a PEM fuel cell, waste heat generation occurs due to: 1) reversible heat of the electrochemical reaction in catalyst layer, 2) irreversible heat due to losses caused by over-potential in catalyst layer, 3) latent heat due to phase change in cathode catalyst layer, and 4) joule heating in all of the fuel cell components including catalyst layer. The mentioned heat sources induce local temperature variations inside fuel cells, which, in turn, highly affect their drying, flooding, and degradation. Accordingly, detailed knowledge about the in situ temperature distribution in PEM fuel cells is essential for efficiently managing water and heat in these systems as well as for minimizing their degradation. A temperature distribution can be obtained through comprehensive structural models for thermal conductivity of different components. The thermal conductivity of PEM fuel cell gas diffusion layers (GDL) is well understood, and some experimental data on thermal conductivity of other components have been provided in literature. However, the thermal conductivity of the catalyst layer, where most of the heat generation modes occur, is still unknown. Accordingly, this work is concerned with structural modeling of this property through a unit cell approach. A detailed geometrical model is developed based on the real microstructural properties of the catalyst layer, and unit cells of various scales are developed. Then, the thermal conductivities of the unit cells are modeled in a mechanistic manner and are interconnected to and integrated with each other to yield the effective thermal conductivity of the whole catalyst layer. In addition to modeling, catalyst layers with different compositions are produced via precise micro-fabrication techniques, their thermal conductivity is tested by transient plane source and guarded heat flux methods, and the experimental values are used to tune and validate the model.
Quinhydrone Formation and Its Impact on the Cell Voltage of the Quinone-Bromide Flow Battery
Authors: Chen Qing , Bombarelli Rafa Gómez , Tong Liuchuan , Marshak Michael P. , Gordon Roy G. , Aspuru-Guzik Alan , Aziz Michael J.
Published: February 2020

Understanding complexation of redox-active species in flow battery electrolytes is important for engineering cell voltage. Complexation between reactants and products of a chemical reaction can significantly shift its thermodynamics. This effect is more pronounced in concentrated solutions. In the quinone-bromide flow battery (QBFB) [1], such complexation, which exists on both sides, is suspected of being responsible for discrepancies of order 100 mV between the measured open circuit potential and that expected from simple Nernstian behavior. Here we focus our attention on the negative electrolyte, where quinone complexes with its reduced counterpart, hydroquinone, to form the quinhydrone dimer. Density functional theory and UV-Vis spectroscopy combine to provide insights into the quinhydrone forming mechanism and evaluate the equilibrium constant. This quinhydrone equilibrium permits the accurate prediction of the measured voltage of a quinone half-cell vs. nominal quinone and hydroquinone concentrations. By further considering tribromide and pentabromide formation on the bromide side, the voltage model explains the linear and sharply ascending cell voltage vs. state of charge behavior observed in the QBFB.

[1] B. Huskinson, M.P. Marshak, C. Suh, S. Er, M.R. Gerhardt, C.J. Galvin, X. Chen, A. Aspuru-Guzik, R.G. Gordon and M.J. Aziz, “A metal-free organic-inorganic aqueous flow battery”, Nature
505, 195 (2014), http://dx.doi.org/10.1038/nature12909
Effect of Co Incorporation of Ordered Mesoporous Sn-Based Alloy Materials for Li-Storage
Authors: Yoon Jeongbae , Park Gwi Ok , Park Su Bin , Kim JI Man , Kim Hansu , Yoon Won-Sub
Published: February 2020

Sn-based intermetallic compound is general concept introducing second metal element to accommodate the inevitable internal strain caused by electrochemically induced volume change between tin and lithium-tin alloy during lithiation and delithiation processes. Particularly Co-Sn intermetallic compounds as an alternative anode material have been widely investigated during last decade due to the high capacity, cycle stability, and high rate performance. To the best of our knowledge, porous nanostructured intermetallic compound has not been investigated as anode for Li-ion battery because of the synthetic difficulty of controlling metal nucleation and sintering.

Ordered mesoporous CoSn intermetallic (CoxSny) with various Co/Sn ratio is successfully synthesized through nano-replication technique as stable and high power anode materials for lithium ion battery. Especially, this is the first result for the synthesis of ordered mesoporous CoSn intermetallic through the direct template method. The electrochemical results show that mesoporous CoxSny exhibits much better capacity than non-porous CoSn. Reversible capacity, coulombic efficiency, and cycle stability of mesoporous CoxSny materials are dependent on their structures and compositions. Especially, 30 atomic % Co contained ordered mesoporous Co0.3Sn0.7 shows 83% capacity retention after 50 cycle, which means Co atoms effectively accommodate the volume strain associates with the lithiation–delithiation processes. The rate performance of mesoporous Co0.3Sn0.7 is significantly improved, which was deeply related to the kinetic behavior such as low charge transfer resistance, large diffusion coefficient (small Warburg factor) and low internal resistance. Sustainable ordered pore structure even after 50 cycle was also observed with TEM, which means Co atoms play a buffer role effectively to accommodate the volume strain associated with the lithiation–delithiation processes.
New Additives to Improve Cycle Performance of Lithium Ion Battery Under High Voltage Conditions
Authors: Konno Kaoru
Published: February 2020

Lithium ion batteries (LIBs) are one of the most versatile secondary batteries with high energy density and high power output.Recently the degradation of LIBs cycle durability has appeared to be one of the significant issues under the use of high voltage conditions.The capacity of LIBs is dramatically decreased after a cycle test in a range of 3.0-4.5 V. The additives for cathodes named “Multi Capture Powder (MCP)” have been developed herein.MCP is capable of capturing metal ions and refraining from cathode decompositions of fluorine compounds.Mechanisms of the effects of MCP on the improvement of LIBs’ cycle performance are different from those of cathode materials examined so far. In case of LiCoO2 (LCO) /graphite cells with 5% MCP added to the cathode, theircapacity retentions have increased by about 10% after 300 cycles under 2.5-4.35 V conditions. Electrochemical impedances between the LCO cathodes with MCP and the graphite anodes after the cycle tests were drastically decreased in comparison with the cells without MCP. In order to clarify the mechanism for the improvement of the capacity retention, the cathodes with/without MCP and the anodes were pulled out of the cells after the cycle tests.The capacity of both the LCO cathodes with /without MCP and the graphite anodes were measured before/after the cycle testsunder 0.2, 0.5 and 1.0 CA conditions with a Li counter electrode. According to the capacity measurements,  the cathode materials including MCP mitigate the capacity loss significantly although the dominent factor of the capacity loss of the cells results in the degradation of the cathodes with/without MCP. After the cycle tests, X-ray diffraction angles for the (003) plane of cathode active materials were shifted to lower than their initial ones before the cycle tests. The shift of the diffraction angles for the cathodes with MCP was smaller than that of those of the cathodes without MCP. MCP plays an important role in improving capacity retention under high voltage cycle test conditions.
High Temperature Lithium Ion Chemistry Development in Saft
Authors: Dong Jian , Greszler Thomas A
Published: February 2020

Several lithium ion battery products with very high power were developed in Saft America Inc. They have wide working temperature from -40oC to 80oC. New chemistry is developed based on those high power cells to emphasize the performance around 100oC. The effect of different chemistry options on the capacity and power aging is investigated.
Highly Dispersed Poly(vinylidene fluoride) and Carbon Black in NMC Cathodes Produced Via Non-NMP Electrovaya Superpolymer 2.0 Processing Method
Authors: Memarzadeh Elmira , DasGupta Rajshekar , DasGupta Sankar , McLean Alexander
Published: February 2020

The development of low cost lithium ion batteries using a non-toxic, non-NMP and low cost production process stands as one of the most promising technology breakthroughs, especially with the surging demand for cost effective solutions for energy storage and electric mobility. We demonstrate for the first time that NMP is not required for achieving a microstructure comprising carbon black and PVDF binder with substantial uniform dispersion throughout the active materials. In turn, well-dispersed conductive additive and binder in the electrode, prepared via Electrovaya’s non-aqueous SuperPolymer 2.0 processing method, is observed via performing extensive microstructure characterization using TOF-SIMS, HAADF, and SEM/EDS techniques. These techniques provide information about the carbon black and PVDF binder distribution and uniformity within the cathode material which turn out to be intimately linked to the electrochemical performance of the battery. The composite cathode NMC material when coupled with graphite in a full cell shows an excellent electrochemical performance on par with other commercial lithium ion batteries that utilize conventional toxic NMP coating methods.
Simultaneous Neutron and x-Ray Tomography for Advanced Battery Research
Authors: LaManna Jacob M , Hussey Daniel S , Jacobson David L , Baltic Elias
Published: February 2020

The current demand of high powered portable electronics and electric vehicles has put significant strain on current battery technology. To improve performance of advanced battery technologies, such as lithium-air, it is critical to understand how reactive species transport and distribute throughout the cell at varying states of charge. Neutron and x-ray imaging techniques allow in-situ visualization of reactants within the battery. X-ray attenuation increases with increasing atomic number while neutron attenuation is more random with strong attenuation by lithium. These techniques can provide complementary data by providing critical microstructure information. To provide access to both techniques, NIST is developing a simultaneous neutron and x-ray imaging facility. The new system orients a 90 keV microfocus x-ray source 90° to the neutron beam to allow for simultaneous tomography as shown in Figure 1. This x-ray system will allow for variable energy, brilliance, and magnification while matching the neutron spatial resolution of 15-50 micron. Matching image resolution of the two beams will allow the overlaying of the two tomograms. Simultaneously imaging batteries will allow reaction species, such as lithium, and solid structure to be resolved at identical conditions which can’t be guaranteed for serial imaging (possibly at different facilities). This presentation will describe the new simultaneous imaging system and evaluate its measurement uncertainties while assessing its abilities using an assortment of batteries including alkaline, Ni-Cd, and Li-ion.

Figure 1
Advances in HE3DA® Thick Electrode Technology Platform for Energy Storage- Performance and Safety Testing
Authors: Prochazka Jan , Stary Radomir , Pavlik Jiri , Zukalova Marketa
Published: February 2020

The HE3DA®concept of several millimeters thick electrodes (3D) gives Li battery incomparable safety and brings a number of new attributes, which are not achievable by the existing thin film technology (2D).

Recently developed and patented internal cooling system, with electrolyte as a cooling media, radically shrinks the battery pack size and extends battery life during operations,

The safe, robust construction with multifunctional frames, easy degassing, low internal resistance and electrolyte exchange and regeneration provides a new lithium accumulator technology ideal for building large energy storage modules.

Performance of a 1kWh HE3DA accumulator will be demonstrated.

Figure 1
Next-Generation Redox Flow Battery Technologies
Authors: Wang Wei , Liu Tianbiao , Sprenkle Vincent
Published: February 2020

In order to enable the large-scale adoption of the redox flow battery technology for grid-scale energy storage, the cost of a redox flow battery system needs to further reduced. Here we report a new redox flow battery chemistry based on soluble commodity redox active materials, which eliminate the need for expensive metal-based redox couples. Compared with other reports in this area, our new redox flow battery technology demonstrated higher voltage, energy density, rate capability, and improved cycling stability (Figure 1).  Recent progress of the advanced redox flow battery technologies research at PNNL will also be discussed, such as new developments on the high energy density electrolyte, high selective membrane, catalytic electrode, as well as nonaqueous redox flow battery technologies.

Acknowledgements

The authors would like to acknowledge financial support from the U.S. Department of Energy’s (DOE’s) Office of Electricity Delivery and Energy Reliability (OE) (under Contract No. 57558). Pacific Northwest National Laboratory is a multi-program national laboratory operated by Battelle for DOE under Contract DE-AC05-76RL01830.

Figure 1.  Voltage profile and the cyclic capacity behavior of the new redox flow battery technology. 

Figure 1
Easily Fabricated Carbon Nanotube Electrodes for Low-Ppb-Level Chromium(VI) Detection
Authors: Wang Chengwei , O'Connell Michael J. , Chan Candace K.
Published: February 2020

Due to its high toxicity, the detection of trace levels of hexavalent chromium, Cr(VI), has attracted much interest in analytical chemistry. Several sensitive techniques have been developed for the determination of Cr(VI), including spectroscopic and electrochemical techniques. For electrochemical detection, mercury electrodes have been demonstrated to be very sensitive for the detection of Cr(VI). The potential toxicity of mercury electrodes, however, limits its practical application. As another good option, gold has become more and more popular, and has also demonstrated to exhibit more electrochemical reversibility than carbon electrodes. However, considering the price and fabrication feasibility for gold, carbon electrodes are still of interest due to the lower price and easy assembly. Recently, Hallam, et al.
1 developed graphite screen printed electrodes for the electrochemical detection of Cr(VI). However, the sensitivity was only ~0.8 nA/ppb and the detection range was 100 to 1000 ppb with a detection limit of 19 ppb, which is much less than those for gold electrodes.2,3 We believe that using nanostructured carbon electrodes can potentially improve these characteristics to match the performance of gold electrodes, resulting in a sub-ppb detection method for Cr(VI).

Here we describe a facile and printable technique to fabricate the electrodes with carbon nanotubes (CNT) for the electrochemical detection of Cr(VI). The electrodes showed currents as high as 500 nA/ppb Cr(VI) for large CNT/filter paper flexible electrodes and ~5 nA/pbb Cr(VI) for CNT/printed electrodes. The limit of detection was shown as low as 5 ppb Cr(VI). The electrode could be deposited on multiple substrates, including FTO glass, flexible gold coated plastic, commercial printed electrodes. We also developed a flow detection system with CNT/printed electrodes, which could detect Cr(VI) continuously and easily similar to a microfluidic system.

References:

1.        Hallam, P. M.; Kampouris, D. K.; Kadara, R. O.; Banks, C. E. Graphite Screen Printed Electrodes for the Electrochemical Sensing of chromium(VI). Analyst
2010, 135, 1947–52.

2.        Jena, B. K.; Raj, C. R. Highly Sensitive and Selective Electrochemical Detection of Sub-Ppb Level chromium(VI) Using Nano-Sized Gold Particle. Talanta
2008, 76, 161–5.

3.        Xu, H.; Zheng, Q.; Yang, P.; Liu, J.; Xing, S.; Jin, L. Electrochemical Synthesis of Silver Nanoparticles-Coated Gold Nanoporous Film Electrode and Its Application to Amperometric Detection for Trace Cr(VI). Sci. China Chem.
2011, 54, 1004–1010.
Structure-Dependent Thermal Defunctionalization of Single-Walled Carbon Nanotubes
Authors: Ghosh Saunab , Wei Fang , Bachilo Sergei M. , Hauge Robert , Billups W. E. , Weisman R. Bruce
Published: February 2020

Covalent sidewall functionalization of single-walled carbon nanotubes (SWCNTs) is an important tool for tailoring their properties for research purposes and applications. In this study, SWCNT samples were first functionalized by reductive alkylation using metallic lithium and 1-iodododecane in liquid ammonia. Samples of the alkyl-functionalized SWCNTs were then pyrolyzed under an inert atmosphere at selected temperatures between 100 and 500 °C to remove the addends. The extent of defunctionalization was assessed using a combination of thermogravimetric analysis, Raman measurements of the RBM, D, and G bands, absorption spectroscopy of the first- and second-order van Hove peaks, and near-IR fluorescence spectroscopy of (n,m)-specific emission bands. These measurements all indicate a substantial dependence of defunctionalization rate on nanotube diameter, with larger diameter nanotubes showing more facile loss of addends. The effective activation energy for defunctionalization is estimated to be a factor of ~1.44 greater for 0.76 nm diameter nanotubes as compared to those with 1.24 nm diameter. The experimental findings also reveal the quantitative variation with functionalization density of the Raman D/G intensity ratio and the relative near-IR fluorescence intensity. Pyrolyzed samples show spectroscopic properties that are equivalent to those of SWCNTs prior to functionalization. The strong structure-dependence of defunctionalization rate suggests a new approach for diameter-sorting of mixed SWCNT samples on relatively large scales without ultrasonic agitation.
Inhibitory and Bactericidal Properties of a Number of Dihydroxyazo Compounds
Authors: Vigdorovich Vladimir , Tsygankova Liudmila , Nazina Tamara , Esina Marina , Shel Natalia
Published: February 2020

Inhibitory and bactericidal properties of a number of dihydroxyazo compounds have been studied in the Postgate medium containing sulfate-reducing bacteria (SRB) in planktonic form. Sulfate-reducing bacterium strain Luk used in this study was phylogenetically closed (99% similarity of 16S rRNA genes) to the type strain Desulfomicrobium apsheronum 1105T isolated from petroleum reservoir. The number of sulfate-reducing bacteria was counted by a method called the direct microscopic count. Special counting chamber was used. Biogenic H2S concentration was defined daily by the iodometric titration. Small concentrations (5-20 mg/L) of the compounds under study have been used. These compounds induce a decrease of the bacterial cells quantity and H2S production by SRB. Dihydroxyazo compounds inhibit carbon steel corrosion and hydrogen permeation through the steel membrane in the presence of SRB. Corrosion tests of the carbon steel samples were carried out by weight-loss method. Most high corrosion rate of steel in the inoculated media is observed in third day of bacteria development when maximum concentration of H2S is reached (190 mg/L). Its value is equal to 0.28 g/(m2h). Protective effect of the bactericides depends on the structure of their molecules. For estimation of hydrogen permeation into metal, two-chamber cell with a vertical steel membrane similar to the Devanathan cell was used. Entrance side of the membrane contacted with the working solution. The measurements were conducted under corrosion potential, cathodic and anodic polarization of the entrance membrane side. The SEM image of the membrane entrance side after the hydrogen permeation test for 2 h in the inoculated media in the absence and presence of the inhibitors is compared. Effect of dihydroxyazo compounds depends on their molecular structure. A presence of nitro-group or Cl-atom and 1-phenyl-3-methylpirazole group in the molecule increases the bactericidal and inhibitory ability of the substance. At that, a number of SRB cells, production of hydrogen sulfide by them sharply decreases, inhibitory effect essentially increases and hydrogen permeation into metal is retarded by 2.5 times in the stationary phase of bacterial vital cycle.
Evaluation of Dezincification Corrosion of Brass By Complex Capacitance
Authors: Tabei Kozue , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki
Published: February 2020

An electrochemical impedance spectroscopy (EIS) was used in order to discuss the detailed dissolution mechanisms because the EIS enables us to discriminate the time constants of elementary steps in the dissolution process. The capacitive loop related to the electrode/solution interface is often observed in the impedance spectrum in the high frequency range when the metal is immersed in the electrolyte solution. Since the electric-double layer capacitance C
dl is related to the surface area and structure of electrode/electrolyte interface, it is generally estimated by the curve fitting of the result of the impedance spectrum. Our group [1] previously reported the calculations of the electrochemical impedance and complex capacitance corresponding to typical equivalent circuits because the precise value of C
dl could be estimated by the capacitance plot. The complex capacitance analysis was applied to the evaluation of the performance of energy conversion devices [2-5].

In the present study, the complex capacitance analysis was applied to evaluation of dezincification corrosion of brass. It is important to estimate the precise value of C
dl because a porous Cu-enriched layer is formed on the brass surface due to the selective dissolution of Zn from brass surface [7]. The evaluation method of the dezincification of brass by capacitance plot was proposed.

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1. M. Itagaki, S. Suzuki, I. Shitanda and K. Watanabe, Electrochemistry, 75, 649 (2007).

2. P. L. Taberna, P. Simon and J. F. Fauvarque, J. Electrochem. Soc., 150, A292 (2003).

3. J. H. Jang and S. M. Oh, J. Electrochem. Soc., 151, A571 (2004).

4. J. H. Jang, S. Yoon, B. H. Ka, Y. H. Jung and S. M. Oh, J. Electrochem. Soc., 152, A1418 (2005).

5. S. Yoon, J. H. Jang, B. H. Ka and S. M. Oh, Electrochim. Acta, 50, 2255 (2005).

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Micron Scale Cathodically Coated Graphene Impedes Corrosion on Ti, Cube, and Stainless Steel
Authors: Staley Patrick Andrew , Metzger Joy , Griffo Danielle , Simmons Emily , Griffo Chris , Bennahmias Mark , Kurtz Russel , Smith Diane K.
Published: February 2020

Graphene has been studied with great interest ever since its unique mechanical and electronic properties were reported a little more than a decade ago. Common experiments involve coating non-carbon surfaces such as paper,1 metal oxide nanoparticles,2 or nickel3in order to either increase their conductivity, or to make them resistant to corrosion. Coating processes often involve mechanical transfer of graphene or chemical reduction of graphene oxide to graphene, but sometimes electrochemical cathodic reduction of the graphene oxide is used in the coating process.

                Here we report the first instance of cathodically coated Ti metal along with cathodically coated stainless steel and copper-beryllium. We report Raman microscope images to verify complete surface coverage of Ti, and partial coverage of ~2 micron islands of graphene on both stainless steel and CuBe. We also report Tafel plotted voltammograms to show that the presence of graphene on Ti shifts the potential of zero current, normally called the “corrosion potential,” in 3.5% NaCl(aq) to a value positive of the formal potential for the O2/H2O redox couple in sea water. We also present Tafel plots which show that the corrosion potential of graphene coated CuBe has shifted positive by 0.1V and the corrosion current decreased by nearly an order of magnitude, and that the corrosion potential of graphene coated stainless steel has shifted positive by 0.3V.

                1. Parvez, Khaled; Wu, Zhong-Shuai; Li, Rongjin; Liu, Xianjie; Graf, Robert; Feng, Xinliang; and Mullen, Klaus. “Exfoliation of Graphite into Graphene in Aqueous Solutions of Inorganic Salts”. Journal of the American Chemical Society (2014) vol 136, iss 16, pp 6083-6091.

                2. Nguyen-Phan, Thuy-Duong; Pham, Viet Hung; Shin, Eun Woo; Pham, Hai-Dinh; Kim, Sunwook; Chung, Jin Suk; Kim, Eui Jung; and Hur, Seung Hyun. “The role of graphene oxide content on the adsorption-enhanced photocatalysis of titanium dioxide/graphene oxide composites”. Chemical Engineering Journal (2011) vol 170, iss 1, pp 226-232.

                3. Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R.; Jennings, G. Kane; and Lolotin, Kirill I. “Graphene: Corrosion-Inhibiting Coating”. ACS Nano (2012) vol 6, iss 2, pp 1102-1108.
A Comparative Study of Mussel Adhesive Proteins As Flash Rust Inhibitors on High Strength Low Alloy Steel
Authors: Hansen Douglas C. , Nelson William F
Published: February 2020

Several proteins found in the adhesive system of the common blue mussel Mytilus edulis have chemical properties which might enable them to inhibit the flash rusting of steels. In this work, Mytilus edulis foot proteins (MAPs) 1, 3, and 5 were purified and applied to HY80 steel in a number of buffer systems containing various amounts of borate, acetate, and phosphate at pH 5.5-7.0. Treated HY80 samples were then monitored in an exposure chamber at 40°C and 100% relative humidity for 7 days. The MAP treatments were also evaluated electrochemically via electrochemical impedance spectroscopy (EIS). The effect of enzymatic crosslinking of the applied proteins using mushroom tyrosinase was also investigated. HY80 samples treated with MAP-1 failed to inhibit corrosion when the protein was dissolved in deionized water, and the effect of MAP-1 on the corrosion on HY80 in buffers containing acetate was not significantly different from the control samples. However, in 0.05M phosphate buffer solution at pH 5.5, enzyme treated MAP-3 and MAP 5 were capable of significantly increasing the time to corrosion and significantly reducing the mass loss of HY80 in the exposure chamber compared to relevant buffer-only controls. The performance of the crosslinked MAP-5 was similar to a commercial temporary corrosion inhibitor applied at the same mass concentration as the protein, suggesting that MAP-5 and similar proteins or polymers may be capable of inhibiting corrosion under certain conditions.