bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitride Supercapacitors: Contribution of Surface Oxide to Charge Storage
Authors: Jampani Hanumantha Prashanth , Patel Prasad Prakash , Datta Moni Kanchan , Kumta Prashant N 
Published: February 2020

With the growing interest in alternative energy sources and the cognitive recognition of the benefits of green energy, there is clearly a pressing need for the development of sustainable and clean energy storage systems (1-3). The scope of electrochemical charge storage devices extends beyond mobile devices into large scale grid level charge storage(4). Load leveling and power quality management applications would be perfectly served by storage of excess charge generated from renewable energy sources in supercapacitors. Supercapacitors are unique electrochemical energy storage devices with high power density and long cyclability. State of the art materials such as high surface area carbons, hydrated ruthenium oxide (5-7) and MnO2 (3, 8-10) suffer from either poor capacity or rate capability.
We have previously demonstrated excellent charge storage behavior of nanoparticulate vanadium nitride on account of the surface reactions occurring on the surface of the oxide exo-shell. However, there is limited understanding into the exact nature of the charge storage behavior and its dependence on the synthesis and processing route. In the present work, we explore the effect of materials processing and electrode properties on the capacitive charge storage in VN based supercapacitors. Dependence of capacitance on particle and electrode properties are evaluated and reported here-in. Tailoring the particle size, crystallinity and porosity are of paramount importance to achieve high capacitances at high scan rates. To gain a fundamental understanding into the charge storage mechanism of nitride materials shown in Figure 1, slurries of the nitride were cast on nickel current collectors and characterized used various materials and electrochemical characterization techniques including X-ray photo-electron spectroscopy (XPS), cyclic voltammetry and electrochemical impedance spectroscopy. Results of these studies will be presented and discussed.

References

1. P. Simon and Y. Gogotsi, Nature Materials, 7, 845 (2008).
2. J. R. Miller, Science, 335, 1312 (2012).
3. R. Kötz and M. Carlen, Electrochimica Acta, 45, 2483 (2000).
4. M. Conte, Fuel Cells, 10, 806 (2010).
5. J. W. Long, K. E. Swider, C. I. Merzbacher and D. R. Rolison, Langmuir, 15, 780 (1999).
6. B. E. Conway, Journal of the Electrochemical Society, 138, 1539 (1991).
7. B. E. Conway, Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications, Kluwer Academic/Plenum Publishers, New York (1999).
8. C. C. Hu and T. W. Tsou, Electrochemistry Communications, 4, 105 (2002).
9. J. M. Miller, B. Dunn, T. D. Tran and R. W. Pekala, J. Electrochem. Soc., 144, L309 (1997).
10. M. Toupin, T. Brousse and D. Belanger, Chemistry of Materials, 14, 3946 (2002).

Figure 1 caption: TEM image of nanoparticulate VN evaluated extensively using various electrochemical methods
Fine-Tuned Nanoporous Supercapacitor Electrode Materials from Renewable Natural Precursors
Authors: Redondo Edurne , Goikolea Eider , Carretero-González Javier , Ségalini Julie , Navarro-Suárez Adriana , Mysyk Roman 
Published: February 2020

Reducing the cost and maximizing the volumetric capacitance are the most critical attributes of current market demand in materials for electrochemical capacitors. The better affordability of electrode materials can be provided by an increased use of renewable biomass precursors instead of traditional fossil precursors of nanoporous carbons such as coals and pitches. The volumetric capacitance can be maximized by fine-tuning synthetic methodology, enabling control over the density of electrode materials through textural properties such as pore size distribution. Renewable natural precursors are generated in abundance, often being industrial waste materials, and are already known to be a source of nanoporous carbons with well-developed microporosity and low admixture content. This has stimulated the present work on alternative carbon precursors with a focus on the optimization of synthetic parameters, primarily targeting high volumetric capacitance and cost-related parameters such as an amount of activating agents and temperature.
Optimum synthesis conditions were defined by thoroughly varying synthesis parameters such as temperature, amounts of an activating agent, etc. Good control over textural properties was enabled through small variations in the synthesis procedures, resulting in a series of microporous carbons displaying gradual changes in pore size distribution within narrow limits. A range of prepared electrode materials exhibited the ion-sieving effect, which is detrimental to supercapacitor operation. Consequently, cost-effective synthesis conditions (the minimum loading of an activating agent and the lowest synthesis temperature) were defined to avoid the ion-sieving effect and provide a volumetric capacitance as high as 150 F.cm-3 per electrode in aqueous electrolyte and 60 F.cm-3 in organic electrolyte with good rate capability (e.g. 90% capacitance retention at a current density of 9 A.g-1 in organic electrolyte) and cycling characteristics. The whole data set generated in the course of refining the synthesis conditions can be used as a guide for adjusting the porosity of the materials to novel electrolytes.
Recovery and Morphological Control of LiCoO2 from Spent Lithium Ion Batteries
Authors: Lim Hana , Jung Ji Hea , Kim Hyun-Jong , Lee Ho Nyun , Son Seong Ho 
Published: February 2020

Nowadays, lithium ion batterys (LIBs) are commonly used electrochemical power source in mobile devices, such as smart phone and lap-top computer, and electric vehicles. As increasing the utilization of LIBs, it must be noted that equal amounts of spent LIBs are produced after lifetime failure. The massive amount of lithium ion battery waste will cause the environmental pollution, increasing energy demand for treatment, and rapid decrease in primary resources, since it contains lots of chemical substances such as Co, Cu, Li, organic electrolytes, and plastics. So, the recycling of major components from LIBs is considered to be a beneficial way to prevent environmental pollution and improve the utilization of the world’s metal resources. Cobalt showed the highest concentration and cost among the recovered materials from LIBs.
In this study, we suggest environmentally benign leaching and separation process of cobalt by using the mild organic acid. And, it was directly used for synthesis and morphological control of Co3O4 and LiCoO2 active materials.
Many organic acids successfully dissolved the cobalt from the spent cathode material. While the leaching efficiency was a little lower than that of sulfuric acid, citric and malic acid showed more than 85% leaching efficiency among the various acids. The difference between citric and malic acids and the others is only that they have one hydroxyl group with 2- or 3- carboxylic acid groups.
After the leaching experiment, the obtained cobalt ion solution was transferred to autoclave vessel with appropriate additives. Under the autogenic pressurized condition, some cobalt compounds were precipitated with the various nanostructures, such as sphere, rod, plate, and fiber. Then, the cobalt compounds were thermally treated in Air environment from 300oC to 900oC to produce nanostructured Co3O4. Also, the Co3O4 and cobalt compounds were respectively mixed with Li2CO3 powder and calcined to re-synthesize the nanostructured LiCoO2. With the appropriate thermal treatment, the nanostructures could be almost passed down from the cobalt compounds to Co3O4 and LiCoO2. XRD results revealed that Co3O4-mediated LiCoO2 had almost same crystallinity and cationic ordering with commercial one. In the case of cobalt compounds-mediated one, however, the cationic ordering that is the ratio of (003) reflection and (104) reflection was lower than commercial LiCoO2. And, the re-synthesized LiCoO2 was also applied to lithium-ion battery and showed very promising performance. More detailed experimental and results will be discussed in our presentation.
Multi-Physics Modeling of Thermal Runaway Propagation in a Li-Ion Battery Module
Authors: Yang Chuanbo , Kim Gi-Heon , Santhanagopalan Shriram , Pesaran Ahmad 
Published: February 2020

Thermal runaway failure of a li-ion battery can be induced for unavoidable reasons, e.g. external heat exposure or mechanical impact. After the initial single cell failure, propagation of such a failure within a battery module or pack shall be prevented to lessening the severity of its consequences. To implement appropriate level of safety and obtain sufficient resistance to thermal runaway cascade, understanding the propagation mechanisms within cells configured electrically in series/parallel is crucial.
For complexity of the propagation phenomena, numerical modeling becomes an effective approach to capture cell and module instant response, identify propagation scenarios, and separate the impact of design factors. A 3-D electrochemical-electrical-thermal model has been developed utilizing NREL’s Multi-Scale Multi-Dimensional (MSMD) modeling approach. This CAE tool integrates electrochemical-thermal performance model, abuse reaction kinetics model of cell components, and electrical-thermal network models at module level. It is designed to be used for addressing the influence of cell or module design factors and evaluating functionality of safety devices on preventing thermal runaway propagation. This model is capable of capturing cell and module response to thermal, mechanical and electrical abuse, e.g. instant electric potential field after nail penetration shown in figure 1 (Figure 1 : Instant eletric potential field after a nail penetration test).
This paper presents our progress on identifying the characterization of thermal runaway propagation in a li-ion battery module. Modeling studies of design factors are carried out to provide design suggestion of improving module resistances to failure propagation. At module level, responses of battery modules with varied electrical configurations are predicted. At cell level, parametric and case studies are carried out to investigate and isolate the impact of other design factors, including cell capacity, chemistry, and type of assembly.
A Novel Aluminium Semi-Fuel Cell with Bipolar Membrane for Water Treatment
Authors: Nikoleishvili Paata , Kveselava Valentina , Tsutsumia Gigla , Gorelishvili Giorgi , Sharabidze Daviti , Kurtanidze Rusudan , Gelashvili Lela 
Published: February 2020

Water is a unique resource that cannot be substituted by alternatives, it requires care and conservation. Unsafe water is a substantial cause of human diseases and death. Effective methods of wastewater treatment from biologically non-degradable harmful pollutants is the application of hydroxyl radicals OH* which are strong oxidants (oxidation potential is E0 = 2,8 V). Formation of OH* in the AOPs is based on chemical, photochemical and photo catalyzed decomposition of hydrogen peroxide in acidic media at pH 3
Fe2+ + H2O2 → Fe3+ + OH* + OH- (1)
O3+ H2O2 → 2OH* + 3/2O2 (2)
H2O2 2OH* (3)
One of the effective ways for solving the problem is development of the electrochemical method for the on-site generation of H2O2 by means of cathodic reduction of oxygen in the fuel cells system and for the carry out of water treatment process directly in catholyte of a fuel cell, which is the main goal of the presented work.
In all fuel cells systems with hydrogen peroxide cogeneration, oxygen is reduced in neutral or alkaline media by the reaction (4). I such case we cannot curried out AOPS (1) in cell, because we must have pH 2.5-3.2.
O2 + H2O + 2ē → HO2
‾
+ OH‾
E0
= -0.065 V (4)
In previous work we developed bipolar membrane aluminium-air semi fuel cell. Bipolar membrane gives us opportunity to create aluminium-air semi fuel cell, where catholyte is acidic solution with pH 2.5-3.2 and as an anolyte we can utilize strong alkaline media.
The bipolar membrane consists of two ion exchange layers of opposite charge in intimate contact. In the applied electric field, the hydroxide ions and the protons produced by water splitting (8) in bipolar junction move towards the respective electrode in the electric field. Water is replenished in the interface by diffusion through the gel-like membrane layers. The driving forces for the transport of these ions are both, the electrical potential and the concentration gradients. The water splitting requires energy that is supplied by the applied electrical field. Do to reaction 8 we can maintain stable pH in cathodic and anodic chamber
Electrode reactions in O2( air)–Al semi- fuel cell:
Anode: 2Al + 8OH‾→ 2AlO2‾+ 4H2O + 6ē E0 = -2.35 V (5)
Cathode: 3O2 + 6H+ + 6ē → 3H2O2 E0= 0.69 V (6)
Total: 2Al + 3O2 + 2H2O + 2OH‾ → 2AlO2‾ + 3H2O2 E0= 3.04 V (7)
Bipolar membrane: 4H2O → 4H++ 4OH‾ E0 = 0.83 V (8)
For water dissociation in the bipolar membrane 0.83 V is required, the electromotive force of the power source will be E0= 3.04 - 0.83 = 2.21 V. The electromotive force is absolutly enough for the cell operation
Model solutions polluted with phenol and p-nitrofenol. Initial COD of solution with pollutant were 500 ppm, after 20 min of treatment in the fuel cell COD decreased to 10 ppm.
Modeling of SEI Layer Growth and Electrochemical Impedance Spectroscopy Response using a Thermal-electrochemical Model of Li-ion Batteries
Authors: Liu Lin , Zhu Min 
Published: February 2020

Lithium-ion batteries (LIBs) suffer severe performance degradation during their lifetime application because of the undesired chemical reactions, ageing, corrosion, structural integrity compromise, and the threat of thermal runaway. Among those degradation mechanisms, much attention has been focused on LIBs materials decomposition, new components formation and growth due to undesired side reactions. The electrode is covered by a passivation layer named as the solid electrolyte interface (SEI), which is one of dominant LIBs degradation mechanisms. The SEI layer affect the LIBs cyclability, life time, power and rate capability, and even their safety. In order to comprehensively investigate the effects of SEI growth on battery performance, a one-dimensional thermal-electrochemical model is developed (1). This model is equipped with a growth mechanism of the SEI layer coupled with thermal evolution, based on the diffusional process of the solvent through the SEI layer and the kinetic process at the interface between the solid phase and liquid phase. The developed model reveals the effects of diffusivity, kinetics, and temperature on SEI layer growth and cell capacity fade. In our model, the SEI growth is accompanied by both diffusion-limited and kinetics-limited processes. With the layer becoming thicker, its growth rate slows down gradually possibly due to increased diffusion resistance. SEI grows more quickly during charge than discharge due to the difference in electron flux through the SEI layer and the temperature change during cycling. Temperature rise due to reactions and joule heating accelerates the SEI layer growth and causes more capacity loss. This model can also provide insights on position-dependent SEI growth rate and be used to guide the strategic monitoring location. Based on the model developed, one more mathematical model is developed to simulate the impedance response of LIBs with considering the double layer capacitance effect (2). The simulated impedance response is analyzed to reveal LIBs impedance behaviors, which can be used to predict the degradation mechanism of LIBs. With combining the two mathematical models, a more accurate equivalent circuit model can be proposed to illustrate the features of LIBs impedance behaviors and degradation mechanism. This work can provide us the insights of combining LIBs EIS analysis with degradation analysis. Currently, the experimental validation is ongoing.
1. L. Liu, W. Lu and A. M. Sastry, Journal of Power Sources, Submitted and under review
2. I. J. Ong and J. Newman, Journal of The Electrochemical Society, 146, 4360 (1999).
Evolutionary Development for Electrokinetic Dewatering of Phosphate Mine Tailings
Authors: Kong Rui , Orazem Mark E. , Huang Yuelong , Yu Dazhi , Lai Han , Moghaddam Saeed , Bloomquist David 
Published: February 2020

The processing and storage of phosphatic clay suspensions (or mine tailings) which result as a waste product from phosphate mining industry represent an important economic and environmental problem. A very long time is required to allow gravity-driven settling of clay suspensions with an initial 2-3 wt% solids content, and decades may be required to reach 25-30 wt% solids content. The associated impoundments occupy over 100 square miles of land in Florida alone.
A combination of experimental and modeling approaches were used to explore the use of imposed electric fields to achieve electrokinetic separation. Batch experiments were used to guide the development of a constitutive relationship describing the changes in solids content with time (t) and applied electric field (E)1,2. A linear behavior between final solids content and Et was found in at short times, and the upper limit of separation was controlled by the value of electric field only.
Subsequently, a semi-continuous system was designed for continuous removal of supernatant water. This system allowed measurement of supernatant turbidity, pH, and changes in solids content as functions of applied electric field, flow rate, and settling time. Under pseudo-steady-state operation, low-turbidity water was separated from a clay solids suspension by a combination of electrokinetic dewatering and free settling.
A semi-continuous system, which introduced a rotating belt between electrodes to facilitate removing clay sludge, was designed and tested. The batch experiment set up was used to optimize fabric selection. This equipment was able to continuously producing thickened clay cake with a solids content of up to 33 wt%. Evaluation of parameters including electrode spacing, electric field, and residence time provided an understanding of the path for optimization. A similiar constitutive relationship as in batch experiment was also estanblished which correlates final solids content to electric field and residence time.
All the systems were also evaluated from an econonic perspective. The energy requirement of the semi-continuous operation that facilitated sludge removal had a lower energy requirement value at a given electric field as compared with the result from batch experiments and the previous semi-continuous operation. All systems followed the trend that high electric fields have a high energy requirement.

References

J.P. McKinney, M.E. Orazem, A constitutive relationship for electrokinetic dewatering of phosphatic clay slurries, Miner. Metall. Process. 28 (2011) 49.

J.P. McKinney, M.E. Orazem, Electrokinetic dewatering phosphatic clay settling areas: numerical simulation and economic assessment, Miner. Metall. Process. 28 (2011) 71.
Electropolishing of Kovar Alloy for Vacuum Applications
Authors: Dündar Yasemin , Karakaya Ishak , Demirci Gökhan , Erdogan Metehan , Aras Mustafa Serdal 
Published: February 2020

Kovar (53% Fe – 29%Ni - 17% Co) is one of the most commonly used materials in high vacuum applications which quite often require electrical isolation(s). Kovar has thermal expansion coefficient close to that of alumina over the range from brazing to cryogenic temperatures. Therefore, joining problems due to difference in thermal expansion coefficients can be minimized when alumina and Kovar alloy are used together.
For the applications that require long vacuum life, Kovar parts should have smooth surfaces to minimize outgas from the surface due to inadequate cleaning. The surface modifications obtained by electropolishing, i.e., preferentially dissolving macroscopic and microscopic surface roughness without grain attack in the depressions, and surface metal oxide layer dissolution [1,2], are indispensable in high vacuum applications. Electropolishing has also long been proven to be a powerful tool for complex parts that are difficult to polish mechanically. Although it is widely used in the vacuum industry, there is very limited information about the Kovar electropolishing in the literature. There is no systematic study known by the authors that aims to reveal the optimum electropolishing conditions for the Kovar alloy.
A two-electrode linear sweep voltammetry was conducted in a solution of acetic acid, chromic acid and water mixture, where a copper plate was used as the counter and reference electrode. A plot of current density versus applied potential given in Figure 1 was obtained at 9°C. In the light of almost constant current density, namely limiting current plateau region observed in this plot, some experiments were conducted at 30 V for durations of 30, 60, 90 and 120 seconds. Rectangular Kovar samples of 15x15 mm dimensions having about 0.50 μmRa initial surface roughness were electropolished to final surface roughness of about 0.25 μmRa. The surface roughness profiles and their microstructures before and after electropolishing process (EP) are given in Figures 2 and 3, respectively.
Figure Captions:
Figure 1: Current density vs. potential graph in acetic acid, chromic acid and water mixture.
Figure 2: Surface profiles of samples, (a) before and (b) after EP. The horizontal and the vertical scales are embedded to left hand side.
Figure 3: Microstructures of samples, (a) before and (b) after EP.
References
[1] Sova, V. (1986). U. S. Patent No. 4,563,257.

[2] Popov, K. I., Djokic, S. S., & Grgur, B. N. (2002). Fundamental Aspects of Electrometallurgy. New York: Kulluwer Academic Publishers. pp.226-227.
Effect of Co3O4 and CeO2 Infiltration on the Activity of a LSM15/GDC10 Highly Porous Electrochemical Reactor
Authors: Ippolito Davide , Hansen Kent Kammer 
Published: February 2020

The reduction of air pollution has become an international concern over the last ten years because of increases in emissions from mobile and stationary sources. Among these sources, volatile organic compounds (VOC) represent a serious environmental problem, together with NOx, SOx and particulate matter, which lead to the formation of ozone in urban and regional areas [1]. The electrocatalytic activity of a porous electrochemical reactor, made of La0.85Sr0.15MnO3±δ (LSM) as electrode and Ce0.9Gd0.1O1.95 (GDC) as electrolyte, was studied for the electrochemical oxidation of propene (C3H6), a major VOC component of Diesel engine exhausts, over a wide range of temperatures. The entire reactor was thought as a highly porous catalytic filter for a possible application in a Diesel exhausts purification system.
The porous reactor was used as a backbone for the infiltration of Co3O4 and Co3O4/CeO2. The effect of the infiltration on the electrochemical properties and catalytic activity of the reactor was investigated by electrochemical impedance spectroscopy (EIS) and gas analysis.
Figure 1 shows the SEM cross-section micrograph of the electrochemical reactor made of 11 alternating layers of electrode (LSM) and electrolyte (GDC).
Figure 2 shows the Nyquist plot of the impedance spectra of Co3O4 infiltrated backbone recorded at OCP with 10% O2 and 10% O2 + 1000 ppm C3H6, 2 L/h, 400 °C.
[1] R. Atkinson, Atmospheric Chemistry of VOCs and NOx, Atmos Environ. 34 (2000) 2063;