bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and Modelling study for Electrocoagulation Cell Used to Remove High Organic Loads in Wastewater
Authors: Cruz-Díaz Martín R , Rivero Eligio Pastor , Torres- Mendoza Angel , Almazán-Ruiz Francisco J. , González Ignacio
Published: February 2020

Electrocoagulation is a very promising technology for cleaning wastewater with high organic content, furthermore, in most of the published papers, experimental studies are performed in beakers with magnetic stirrers, unfortunately this type of laboratory scale, as such may not be scale-up. In this work, a laboratory scale electrocoagulation cell has been designed to operate in batch and continuous flow mode, which can be scale-up to processing larger volumes of effluents with high organic matter content of the food and liquors industries, which are difficult to treat by biological methods. The laboratory scale electrocoagulation cell (CEEL-TUU01) [1] is built in polycarbonate with carbon steel electrodes 1018 with thickness of 1/8". The main objective of this work is to develop a modeling and experimental methodology to establish the operating conditions for this cell. The methodology consisted of: a) physicochemical characterization of the effluent, b) microelectrolysis studies, c) chemical coagulation, d) thermodynamic analysis, e) kinetic studies of electrode dissolution and gas generation (H2 and O2), f) for cell operating in batch mode, the effect of the inter-electrode gap on pH changes was studied, g) to find the flow cell operating in continuous mode, experimental studies of the residence time distribution (RTD) were conducted, Finally, h) macro electrolysis studies were performed using food and liquors effluents. Using the methodology here propose the operating conditions of the electrocoagulation cell for to clean effluents of the food and liquors industries (98% COD removal and almost 100% removal of the effluent turbidity) were establish. The RTD curves were approximated with two no ideal reactor design mathematical models: i) N-tanks in series (N-CSTR) and ii) axial dispersion model (MDA), likewise to detect local deviations of the flow pattern within cell, computational simulation studies of hydrodynamics (Comsol Multiphysics 4.2 software) were carried out. The generation of gas bubbles (hydrogen) in the cathode positively modify the liquid flow pattern and the axial dispersion model (MDA) could be considered as the design equation for the liquid phase cell. The hydrodynamic simulation results helped to identify punctual defects in the geometric cell design. Finally, the strategy developed aid in the design and re-design of an electrocoagulation cell.

[1] A. Torres-Mendoza, P. E. Mendoza-Campos, I. Rodríguez-Velázquez, P. Benítez. M. R. Cruz-Díaz, E. P. Rivero , I. González. Extended Abstracts of XXXII Encuentro Nacional y 1er Congreso Internacional de la AMIDIQ. 3 al 6 de mayo del 2011, Riviera Maya, Quintana Roo. p 3109-3115
On the Electrocatalysis for Organic Mineralization on BDD: Ab Initio Calculations and Microscopic Studies
Authors: Jaimes Raciel , Ugalde Victor Manuel , Vázquez Jorge Gabriel , Galvan Marcelo Enrique , González Ignacio
Published: February 2020

Boron doped diamond (BDD) can efficiently mineralize recalcitrant organic pollutants from water oxidation, however, it has not met the minimum requirements for industrial applications due to expensive manufacturing. Accordingly, there is a need to identify the physicochemical features associated with such capacity (i.e. enhanced generation of weakly adsorbed hydroxyl radicals), in order to develop new catalytic materials with similar performance and feasible commercialization. In order to contribute to this effort, this study presents a surface analysis for BDD conducted with scanning tunneling microscopy (STM), atomic force microscopy (AFM) and scanning electronic microscopy (SEM), as well as plane waves models to account for its electronic structure. The determination of the most stable sites for the location of the boron atom across the layered structure, along with the preferential reactive sites on BDD is discussed on the basis of this theory. STM imaging is simulated by Density Functional Theory (DFT) calculations using the local density of states. Morphological and conduction variations on BDD surface are collected using a Scanning Electrochemical Microscopy (SECM), to identify the potential regions for the electrocatalysis of water oxidation.
Electrocoagulation of an Industrial Wastewater Using Copper Electrodes
Authors: Carbajal-Clemente Carlos A. , Barrera-Díaz Carlos , Roa-Morales G. , Balderas-Hernández Patricia
Published: February 2020

The electrochemical method of electrocoagulation allows to effective elimination of the organic contamination present in the residual wastewaters. The electrocoagulation is an operation that employs electric energy as promoter of electrochemical reactions in which there are dissolution of the sacrifice anodes, they allow the production in situ of coagulants agents, which destabilize an emulsion and they allow percent high chemical demand removal of oxygen (DQO), biochemical oxygen demand (DBO), total solids, fecal coliforms and turbidity (1-3).

This project perform a study of an electrocoagulation process using copper (Cu), as sacrifice electrode for industrial wastewater with the objective of improving the water quality, the evaluation and optimization of key variables like pH and the current density are presented and discussed.

A batch cylindrical electrochemical reactor containing a pair of Cu electrodes was used for electrochemical tests. Each electrode was 20.0 cm by 2.5 cm with a surface area of 50 cm2. Batch volumes of 0.3 L were treated in a 1.0 L glass reactor. A direct-current power source supplied the system with 0.5, 1.0 and 2.0 amperes, corresponding to current densities of 10, 20, and 30 mA/cm2. COD, turbidity and Color were used as indicators for obtaining the improving waster quality

Figure 1 shows the results of the COD removal as a function of treatment time at different initial pH values. As observed the best removal takes place at an acidic pH value reaching a 70 % removal. This can be explained since the Cu ions are present in wastewater as a free ion when the pH is low. However, when the pH of the solution is increases the formation of Cu(OH)2(s) takes place and the removal of all colloidal mater occurs.

References

Grandon, Rodrigo; Hansen, Henrik and Nuñez, Patricio. (2006). Electrocoagulation as a remediation tool for wastewaters containing arsenic. Minerals Engineering. Vol. 19, No. 5; p. 521-524

Muttucumaru, S. (2009). Review of pollutants removed by electrocoagulation and electrocoagulation/flotation processes.

Rajashwar, K. and Ibañez, J. Environmental electrochemistry: (1997). Fundamentals and Applications in pollution abatement. San Diego, California: Academic Press limited. P. 776
Iron Electrodeposition at High Surface Area Activated Carbon Material Using a Rotating Disk-Slurry Electrode Technique
Authors: Bañuelos Jennifer alexis , Rodriguez Valadez Francisco Javier , Godínez Mora-Tovar Luis Arturo
Published: February 2020

An effort to devolop an electrochemically smaller and well- dispersed iron material on a high surface area carbon material is required for heterogenous Electro-Fenton applications. Iron has been the most common metal used in Electro-Fenton process. Here, a rotating disk-slurry electrode (RoDSE) technique is presented as a method to electrochemically prepare bulk Fe/carbon material avoiding a constant contact of the carbon support to an electrode surface during the electrodeposition process. The Fe/carbon material was prepared by using a slurry solution that was saturated with activated carbon in 0.1 M H2SO4. The iron precursor added to the slurry solution was FeCl3. The electrochemically prepared Fe/carbon was characterized and electrochemical experiments were carried out to examine their degradation activity for a typical dye and stability compared with a homogenous Electro-Fenton process. The RoDSE material showed major and faster degradation demonstrating that the use of the RoDSE technique is an effective method to prepare bulk quantities of activated carbon-supported iron for heterogenous Electro-Fenton applications via an electrochemical route.
Al Recovery and Reuse for Wastewater Treatment
Authors: Gamboa Judith , Barrera-Díaz Carlos , Roa-Morales G. , Varela-Guerrero Victor
Published: February 2020

Electrocoagulation is currently an emerging technology presented as an alternative for wastewater treatment, offering great potential in the removal of many different contaminants in wastewater from different sources [1].

In this work Tetra Pak packages were used to obtain Al electrodes. Al disc were made with 1,250 grams of aluminum recovered at a pressure of 6 tons for 2 minutes and these were used as electrodes for the electrocoagulation process

Electrocoagulation was performed at a current of 7.5A for 30 minutes at initial pH of 8. Up to 80 % removal of color and COD 47.97 % was observed when commercial aluminum electrodes and 77.81 % are used in color and COD of 47.57 % when the recovered aluminum electrodes were used (see Fig. 1). Therefore we can use the recovered aluminum electrodes as an alternative for the treatment of wastewater.

[1]
M. Mechelhoff, G. H. Kelsall y N. J. Graham, «Electrochemical behavior of aluminium in electrocoagulation processes,» Chemical Engineering Science, vol. 95, pp. 301-312, 2013.
Rapid Degradation of Malathion By Solar Photo-Electro Fenton Process Using an Oxygen Diffusion Cathode
Authors: Palacios-Rodriguez Gustavo Adolfo , Hinojosa-Reyes Laura , Guzmán Mar Jorge Luis , Hernández-Ramírez Aracely , Villanueva-Rodíguez Minerva , Ruiz-Ruiz Edgar Jocsan
Published: February 2020

Malathion is a well-known organophosphate pesticide that is still used in Mexico and in other countries of Latin America in attempts to control several insect plagues. It is applied in citrus crops and urban zones. Due to its extended use, Malathion can become a water pollution problem.

In this work, results of degradation and mineralization of Malathion by Solar Photo electro-Fenton using an oxygen diffusion cathode are described. Previously, a factorial experimental design 32 with three repetitions in the central point and desirability function approach were applied to investigate de H2O2 production in the oxygen diffusion cathode. The effect of current density and support electrolyte were selected as factors, while produced H2O2 concentration and current efficiency were considered as response functions. From the statistical design prediction, the optimum condition for H2O2 production were 1 A of current density using 1 M Na2SO4 as electrolyte support generating up to 36 mM H2O2. Under these conditions, Solar Photo electro-Fenton process was applied for 10 and 30 mg/L Malathion solutions. The degradation by anodic oxidation and electro-Fenton were also compared. The process was more efficient for the lower initial concentration of the pollutant. The results showed that the mineralization of Malathion by solar photoelectro-Fenton process and the photo electro-Fentonprocess for 10 mg/L Malathion were 100% and 80%, respectively, after 240 min of reaction.
Degradation of 4-Clorophenol By Electro-Fenton Using Electrodes of Graphite
Authors: Santana Germán , Nartividad Reyna , Roa Gabriela , Martín del Campo Eduardo
Published: February 2020

Electrochemical Advanced Oxidation Processes (EAOP) have been proposed like alternative processes for the treatment of industrial wastewater this is due to their high effectiveness in removing toxic organic compounds, low operating costs and minimum consumption of chemical reagents.

In this work the main purpose is to find the better conditions to degradate an organic compound in this case 4-Clorophenol by Fenton´s reaction.

Electrolytic System. Electrochemical cell is an undivided glass cell of 1 Liter. The electrodes (anode and cathode) are made of graphite. An oxygen flow of 50 mL*min-1 feeds with a diffuser to electro-generate hydrogen peroxide (H2O2) in situin the cathode.

The diffuser, furthermore of provide oxygen also generates a bubble matrix which increase the velocity of mass transfer from the ions situated in the electrolyte to the electrodes surface.

For applying constant current is necessary a power supply which maintaining a current at 0.2 A. In this case the support electrolyte is Na2SO4 0.05 mol*L-1, this solution was adjusted to pH=3.0 with sulfuric acid.

With the above conditions, an experiment with a volume of 900 mL of electrolyte solution were conducted to electro-generate H2O2. The determination of the concentration of H2O2was followed by spectrophotometry UV-Vis at λ=408nm in an equipment HACH DR 500.

Knowing that is possible to electro-generate H2O2
in situ in this electrochemical cell it was decided to carry out Fenton´s reaction. For this purpose the ions Fe2+were obtained from an iron piece which was placed within the cell and it was not connected to the circuit.

To prove the catalytic activity of iron (Fe2+) and the oxidizing power of the radicals hydroxyls generated by Fenton´s Reaction, was added 4-Clorophenol to the electrolyte solution, maintaining the same reaction conditions of the electro-generation of H2O2. The degradation of 4-Clorophenol was followed by the determination of Total Organic Carbon (TOC) with an equipment Shimadzu TOC-L.

Results show that the solution initial concentration is 59.39 mg*L-1 of TOC which decrease until 33.26 mg*L-as result of 3 hours of treatment by Electro-Fenton reaction, this is a 43.8% of remotion from initial concentration of 4-Clorophenol. This implies that this process must be improve to mineralize completly organic compounds and reduce treatment time.

References.

[1] Agladze G, Tsurtsumi G, Jung B, Kim J, Gorelishvili G. Journal of Applied Electrochemistry. 2007. 37 (385-393).

[2] Brillas E, Sauleda R, Casado J. Journal of the Electrochemical Society. 1998. 145 (759-765).

[3] Peralta E, Natividad R, Roa G, Marin R, Romero R, Pavon T. Sustainable Environment Research. 2013. 23 (259-266).

[4] Song-Hu, Xiao-Hua L. Journal of Hazardous Materials. 2005. 118 (85-92).

[5] Stasinakis A. Global Network for Environmental Science and Technology. 2008. 10 (376-385)
A Computational Study of Nickel Migration in SOFCs Anode Due to Phosphine Induced Degradation and Applied Electrical Current
Authors: Sezer Hayri , Celik Ismail Bektas
Published: February 2020

The poisoning of Solid Oxide Fuel Cells (SOFCs) anode materials by impurities in coal syngas is a significant problem for utilization coal symgas in SOFCs. One such impurity, phosphine is known to cause catastrophic failure of SOFC anode at ppm level concentrations (below 10 ppm). A significant phenomenon observed in SOFC anodes, made of Ni-YSZ cermets, exposed to phosphine is migration of the nickel from porous matrix to the surface, which is believed to be one of the reasons for performance degradation. The mechanisms responsible for the experimentally observed Nickel migration are not well understood. A possible mechanism, which considers the Nickel diffusion and the formation of secondary phases (Ni-P compounds) as responsible phenomenon of Nickel migration, was proposed by our group. However this consideration does not allow us to predict the experimentally observed effect of the applied current. In this study, a reasonable mechanism is proposed to reveal the effect of electrical current on Nickel migration in SOFCs. The postulation of this mechanism is that the applied electrical current could possibly cause the transport of Nickel by generating an electrical force in the current flow direction. In SOFCs, the electrical current flows from anode/electrolyte interface to anode/fuel interface. Therefore the direction of the Nickel transport is from anode active layer to the anode surface. A transport model for nickel migration is formulated based on these postulations and it is integrated into an existing one dimensional in house code for predicting SOFC anode degradation due to fuel impurities. Simulations show that the proposed mechanism of Ni diffusion driven by secondary phase formation and the electrical force can reveal the experimentally observed accumulation of Ni and secondary phases on the SOFC anode surface when driven by a current and exposed to phosphine.
Removal of Sulfates Containing in Water, by an Electro-Coagulation Process
Authors: Carreño Gilberto , HernÁndez Venus AMANDA , Fuentes Rosalba , Baltazar Juan CARLOS , Ortiz Josefina , Carreon JosÉ JUAN , Arias Luz ADRIANA
Published: February 2020

Guanajuato City population is 110,000 habitants. The city uses as a drinking water source two water reservoirs. These reservoirs supply approximately 40% of the city demand; the difference is pumped from a granular aquifer (alluvial deposits) which is recharged by percolation though fractured rocks in the highlands. To the reservoirs got drainage of abandoned mines. There are more than 20 mines that drain year round relevant amounts of sulfate waters. This problem is extreme during the dry season, when the only water in the creeks is the mine drainage water (Ramos-Arroyo, et al., 2011).

This work presents a study of sulfate removal from a solution that simulates mine drainage in Guanajuato region (sulfate concentration 1400 ppm), by electrocoagulation (EC) method, using aluminum as a sacrifice anode in a lab scale electro-coagulation reactor. The couplings with a phytoremediation process improve better result. The removal of sulfates with the coupling of these two methods was satisfactory; decreasing the sulfate concentration around 90%. Results are also presented of sulfate removal from different abandoned mines drainage in Guanajuato, Mexico. Sulfate removal is followed during EC and the phytoremediation test, using HPLC and UV-vis.

The electrocoagulation method has shown good results in the removal of arsenic and sulfates (Primitivo, et al., 2014). This work presents also the results with different sulfate concentrations, types of water and the coupling of the EC method with another different method ( phytoremediation), to reduce costs and increase the percentage of removal of sulfates.

We thank the financial support given by CONACYT-CONCYTEG through the project GTO-2012-C04-195057

References

1.- Removal of arsenic and sulfates from an abandoned mine drainage by Electrocoagulation. Influence of hydrodynamic and current density. Primitivo Del Ángel, Gilberto Carreño, José L. Nava, Martín T. Martínez, Josefina Ortiz. Int. J. Electrochem.
Sci., 9 (2014) 710 – 719

2.- Afectaciones del Drenaje de Minas Abandonadas al Abasto de Agua Potable en Guanajuato, México. Y. R. Ramos-Arroyo, F. Ramírez-Navarro, J. Martínez-Arredondo, D. Muñoz-Cancino, I. Rodríguez-Huerta, G. Carreño-Aguilera, Macla, 15 (2011) 175.
Model Based Battery Management System (BMS) for Electric Transportation and Renewable Microgrids
Authors: Subramanian Venkat R.
Published: February 2020

Lithium ion batteries are a promising technology to reduce the dependence on fossil fuels for transportation and for the creation of resilient and reliable renewable microgrids. However, battery manufacturers overdesign lithium ion batteries used in electric vehicle to ensure safety and life due to the uncertainty of the internal states of the cell. Proactive battery management systems (BMS) and advanced sensing technologies offer an opportunity to significantly reduce the cost and weight of transportation batteries, and circumvent problems arising due to capacity fade and safety concerns. This talk will describe how multiscale electrochemical engineering models, mathematical model reformulation and the use of robust algorithms can alleviate some of these problems to help electrify the transportation industry by improving the range of variables that are predictable and controllable in a battery in real-timewithin an electric vehicle. The use of battery models in a BMS will be analyzed. The interplay between the fundamental depth in modeling, choice of numerical algorithms, and application driven problem formulation will be presented. The validity of implementation in a microcontroller environment for model predictive control (MPC) will be addressed and demonstrated. In addition, preliminary results on aggressive sizing and control strategies for batteries in renewable microgrids will be presented.

Acknowledgements: I would like to acknowledge my current and past students and postdoctoral associates for the results presented.
A Time Dependent Model of Electroless Deposition of Co-Mn Alloy
Authors: Gomez Jamie , Kalu Egwu Eric
Published: February 2020

A time dependent model of electroless cobalt-manganese deposition will be presented. The results are obtained from the development of a time-dependent mathematical model for the electroless deposition of cobalt based on fundamental principles. The experimental conditions used to develop this model include, temperature of 80oC and pH of 8.5. The governing equations take into account mass transport by migration and diffusion and Butler Volmer kinetics. The model can be used to predict the concentration profile of each species in the solution and the thickness of composite deposit. The simplifying assumptions made in model equations derivation have significant influence on the accuracy of the model predictions.
Synthesis of Nickel-Cobalt Difluoride [NixCo(1-x)F2] for Lithium Ion Batteries Application
Authors: Teng Yin Ting , Wei Fengxia , Yazami Rachid
Published: February 2020

Introduction

Transition metal fluorides have been gaining interest as reversible positive electrodes for rechargeable lithium batteries in the recent years due to their high theoretical e.m.f values and their ability to transfer more than 1 electron per formula unit.1 Among the metal difluorides, CoF2 and NiF2 have the highest calculated theoretical discharge voltage1. However, previous experimental work conducted has shown that nanostructured CoF2 has a discharge voltage of about 1.4V and an initial discharge capacity of about 550 mAhg-1. 2 The discharge capacity of 550 mAhg-1 relates to a 2 electron transfer per formula unit of CoF2. As for NiF2, it has previously been reported to have a discharge voltage of about 1.5 V with an initial discharge capacity of about 700 mAhg-1.3 Comparison of their effective ionic radius shows that Ni2+ has an effective ionic radius of 0.70 angstroms while Co2+ with an octahedral coordination has an effective ionic radius of 0.745 angstroms4. This indicates the possibility of the presence of a mixed nickel-cobalt difluoride [NixCo(1-x)F2]. However, the presence of [NixCo(1-x)F2] has never been reported. Our recent work presents the synthesis and the electrochemical properties of nanostructured mixed nickel-cobalt difluoride [NixCo(1-x)F2] in the sizes from 15 nm to 80 nm. Bond valance sum analysis conducted shows that Ni and Co are still in the oxidation state of +2. EDX mapping demonstrated a homogeneous mixing of nickel, cobalt and fluorine which confirms the successful synthesis of [NixCo(1-x)F2] with no phase seperation. Bond length calculations show a decrease in the metal-fluorine bond length as the nickel content was increased, hence leading to a smaller unit cell with smaller crystallites. Lattice parameters calculations conducted on the [NixCo(1-x)F2] show a slight positive deviation from Vegard’s law. Lastly, the possibility of voltage tuning via having a mixed nickel-cobalt difluoride [NixCo(1-x)F2] was also demonstrated in the work.

References

1. Li, H., Balaya, P. & Maier, J. Li-Storage via Heterogeneous Reaction in Selected Binary Metal Fluorides and Oxides. Journal of The Electrochemical Society 151,A1878 (2004).

2. Teng, Y. T., Pramana, S. S., Ding, J., Wu, T. & Yazami, R. Investigation of the conversion mechanism of nanosized CoF2. Electrochimica Acta 107,301–312 (2013).

3. Lee, D. H., Carroll, K. J., Calvin, S., Jin, S. & Meng, Y. S. Conversion mechanism of nickel fluoride and NiO-doped nickel fluoride in Li ion batteries. Electrochimica Acta 59,213–221 (2012).

4. Shannon, B. Y. R. D. et al.Revised Effective Ionic Radii and Systematic Studies of Interatomie Distances in Halides and Chaleogenides Central Research and Development Department , Experimental Station , E . L Du Pont de Nemours The effective ionic radii of Shannon & Prewitt. Acta . (1976).
Electrochemical Insertion/Deinsertion of Mg2+ Ions into MnO2 Nanowires
Authors: Song Jaehee , Noked Malachi , Lee Sang Bok
Published: February 2020

The increasing demand for rechargeable energy storage devices has generated great interest in battery systems that could replace the high-cost lithium based batteries. Among various candidates, magnesium-ion (Mg-ion) batteries are considered one of the most promising alternatives due to the abundance and better stability of magnesium compared to those of lithium. However, despite the similarity in ionic size between Li+ and Mg2+ ions, Mg2+ ions exhibit very slow solid-state insertion/deinsertion kinetics with the cathode materials currently used for Li-ion batteries. The sluggish Mg2+ insertion/deinsertion kinetics is presumed to be the result of the divalent characteristic of Mg2+ ions, which leads to a strong electrostatic force between the Mg2+ ions and the hosting material. For instance, poor electrochemical insertion/deinsertion performances of Mg2+ into manganese dioxide (MnO2) has been reported in previous studies which suggest that the strong ionic characteristic of MnO2 hampers the Mg2+ insertion into its lattice.

We investigated the electrochemical insertion/deinsertion behaviors of Mg2+ ions with nanostructured MnO2 by utilizing various spectroscopic and microscopic techniques. We determined the stoichiometry of Mg2+ ions and MnO2 at various charged states as well as with various electrode structures and electrolyte conditions by directly analyzing the inserted amount of Mg2+ ions with inductively coupled plasma – optical emission spectroscopy (ICP-OES). In addition, we studied the effect of the water content of the organic magnesium electrolyte, motivated by previous studies where water molecules had a positive effect on Mg2+ insertion behavior into layered-structure V2O5. We found that the sluggish Mg2+ insertion/deinsertion behaviors into MnO2 can be suppressed by the presence of a small amount of water in organic electrolytes, presumably due to the preferential solvation of Mg2+ ions by water molecules, which could “shield” the divalent charge of Mg2+ ions and reduce the electrostatic force between MnO2 and Mg2+. The cyclic voltammogram measurements showed that there was no considerable degree of Mg2+ insertion/deinsertion reactions in pure organic electrolytes whereas distinct peaks, responsible for Mg2+ insertion/deinsertion, were observed in water-containing electrolytes. In addition, we found that the nanostructured MnO2 electrode delivered improved Mg2+ insertion/deinsertion capabilities compared to the planar MnO2 electrode due to the shorter ionic diffusion length and high surface area of nanostructure, allowing the Mg2+ ions to overcome the electrostatic force.
Nanostructured MgFeSiO4/C Cathode Prepared By a Modified Sol-Gel Method for Rechargeable Mg-Ion Batteries
Authors: Chen Xinzhi , Vullum-Bruer Fride
Published: February 2020

The rechargeable magnesium ion battery is currently investigated in response to several challenges of lithium ion batteries,[1] such as cost, resource availability and safety issues related to risk of thermal runaway. The lithium ion batteries have and are predicted to dominate the portable battery market for a long time due to the high superior power density, while rechargeable magnesium batteries may play an important role in stationary energy storage systems and auxiliary power applications where the low cost and high reliability under a wide temperature range are more important than low weight and high power density.

Based on similar principles as the lithium ion battery, rechargeable magnesium ion batteries involve a reversible insertion/extraction of magnesium ions into/from a host matrix (cathode or anode materials) during the discharging and charging, and two electrons can be transferred accompanying one magnesium ion migration. Thus the specific volumetric capacity of magnesium metal can reach 3833 mAh/cm3, which is higher than that for lithium metal (2046 mAh/cm3). [2]

Similar to lithium ion batteries, it is mainly the cathode materials which limits the batterie’s properties such as energy density, safety and life cycle. In this work, nanostructured MgFeSiO4/C composite cathodes are prepared by a modified sol-gel method combined with carbothermal reduction. Fig. 1 demonstrates the Pawley fitting of the X-ray diffraction for the MgFeSiO4/C composite. The composite materials are investigated electrochemically using the developed composite materials as the cathode, magnesium alloys as the anode and a state-of-the art electrolyte. And in situXRD is used to characterize phase evolution in the materials during cycling.

1. Novák, P.; Imhof, R.; and Haas, O., Magnesium insertion electrodes for rechargeable nonaqueous batteries — a competitive alternative to lithium? Electrochimica Acta, 1999. 45(1–2): p. 351.

2. Yoo, H.D.; Shterenberg, I.; Gofer, Y.; Gershinsky, G.; Pour, N.; and Aurbach, D., Mg rechargeable batteries: an on-going challenge. Energy & Environmental Science, 2013. 6(8): p. 2265.
High Energy and High Power Electrically Rechargeable Zinc-Air Battery
Authors: Toussaint Gwenaëlle , Stevens Philippe , Rouget Robert , Fourgeot Fabrice
Published: February 2020

Zinc air batteries use very cheap raw materials (Zinc, Carbon, Potassium Hydroxide) with material costs less than 10€/kWh. The fact that they are water based batteries also makes them much safer and they use environmentally benign and recyclable materials. There is no possibility of thermal runaway or fire either. Zinc-air batteries are therefore an interesting option for the electric vehicle, but also for lower cost stationary storage.

High energy density zinc-air batteries are already on the market with energy densities above 400 Wh/kg but they are not rechargeable. The technology to make zinc-air batteries on an industrial scale therefore already exists. The challenge now is to be able to make zinc-air batteries rechargeable.

Attempts to develop such a battery have failed due to the poor reversibility of the air electrode and due to the formation of zinc dendrites during charge. By using 3D electrode structures and a protected air electrode, an electrically rechargeable zinc-air battery has been developed which has solved these problems and which has high cycle efficiencies.

One of the disadvantages of metal-air batteries is their poor discharge power performance compared to Lithium-ion batteries. The culprit is the air electrode, the zinc electrode is not limited on discharge. Oxygen reduction is a multi-electron reaction with slow kinetics. The reaction is further impaired by the low concentration of the active material (oxygen from the air) and the low molar density of a gaseous reactant.

The addition of a second high power cathode has solved this problem and has brought very interesting power and energy performances to our zinc-air battery.

High energy densities have also been achieved using zinc electrodes with very high loadings, up to 630 mAh/cm².

These zinc-air cells are tested under standard cycling conditions, but also using normalised electric vehicle driving cycles.
Generalized Simulation Models of Transport Processes within Sodium-Sulfur Batteries
Authors: Mason Jerry Hunter , Wu Fan , Celik Ismail Bektas
Published: February 2020

With the ever growing demand for energy and drastic issues related to global warming, energy storage and production are becoming even more important issues. The development of large capacity energy storage devices to be used in conjunction with renewable energy resources can help meet these demands. Due to the cost of materials and time consuming testing procedures, development of new battery and fuel cell technology is a slow and expensive practice. Recently, progress has been made regarding solid electrolyte materials for Sodium-Sulfur cells which will allow for significantly lower operating temperatures. The purpose of this report is to present the capabilities of two models designed to aid in the technical design process of Sodium-Sulfur cells. A zero-dimensional, transient, lumped model derived from an integral analysis of the transport of mass, energy and charge throughout the battery has been created. Additionally a 3-dimensional, unsteady, multiphase continuum simulation model for Sodium-Sulfur batteries using general electrochemical models has been developed. Together these tools aim to decrease the time and expense required to complete the design procedure. Transport processes, including energy, specie and charge transfer, are simulated numerically by discretizing their respective equations. The processes are coupled with the use of Faraday’s law of electrolysis and solutions for the species concentrations, electrical potential and current density are produced in a time marching fashion. For the continuum model, a generalized grid generation strategy allows for meshing of square planar, circular planar and cylindrical cells with electrodes and electrolyte of varying thickness and mesh densities. The model is also capable of performing simulations with unique geometries through the use of immersed boundary method. Properties required for solving the transport equations, such as fluid density and ionic conductivity, are calculated and updated at each grid location as a function of time based on the volumetric content and phase of each species within the control volume surrounding each node. Specie boundary conditions consist of both open and closed electrodes, which closely model certain fuel cell and battery designs respectively. Electro-chemical boundary conditions can be as simple as a prescribed voltage or current density or more practical such applying circuitry including resistance, power consuming or power producing loads (for the purpose of charging). The present model was developed for Sodium-Sulfur cells but could be adapted to study the behavior of seemingly any theoretical battery under given operating conditions with the use of small scale experimental results for model calibration and verification. Such a tool could be used to expedite and reduce costs of the iterative design process of new energy storage technologies.
Electrochemical Activity of P2 Structured Na-M-O Cathode for Sodium Ion Batteries
Authors: Yu Chan-yeop , Myung Seung-Taek
Published: February 2020

A market of plug-in electric vehicles (PEV) or hybrid electric vehicles (HEV) using lithium ion battery is being expanded, then demand for large-scale energy storage devices is increasing gradually. However, percentage mass of lithium in the earth is only 0.006%. Indeed, the cost of lithium resource increased after commercialization in 1991, might be soared when EVs or energy storage systems (ESS) are used. Sodium resource, the element which is quite abundant (Clarke’s number is 2.64), can be an alternative for the expensive and rare lithium. For those reasons, development of sodium ion battery is essential for solving previous problems. Recently, P2-phase materials are widely attracted due to their large initial capacity. However, obvious capacity fading is shown in almost P2 type active materials. In this study, we report to synthesize P2 structured Na-M-O (where M is transition metal) compounds and investigate physical and electrochemical behaviors of the Na-M-O cathode for sodium-ion batteries.

The Na-M-O powders were synthesized by solid-state method. Stoichiometric mixture of Na2CO3 and precursor were mixed by ball-milling. Then the mixed powders were pelletized, and the pellets were calcined at high temperature. After calcination, heated pellets were quenched. All chemicals and products were handled in an Ar-filled gloved box to avoid air exposure. Phase identification of calcined products was done by X-ray diffraction (XRD) with Cu Kα radiation and the collected XRD data were analyzed by using the Rietveld refinement program, Fullprof. Electro-chemical test were carried out in a 2032 coin type sodium cell. Galvanostatic electrochemical charge and discharge tests in 0.5M NaPF6 EC:DEC solutions were carried out at room temperature. Also, the products were characterized by SEM, TEM and so on.

The XRD patterns of Na-M-O compounds were obtained without impurities peak, respectively. The produced materials showed P2 phase even if adding other transition metal elements. Electrochemical tests were observed in the potential domain between 2.0 and 4.5 V at 20 mA g-1 current density. Initial capacity of Na-M-O electrodes showed high capacity. And the capacity retention was significantly improved by adding other transition metal elements. Details will be discussed in the conference site.
Synthesis and Electrochemical Characterization of P2- and O3-Phase Na2/3Fe1/2Mn1/2O2 Layered Oxide
Authors: Han Man Huon , Acebedo Begoña , Gonzalo Elena Candida , Rojo Teófilo
Published: February 2020

The commercial success of Li-ion batteries over last decades leads to large investments in developing safer battery with bigger capacity and less expensive materials and the application of Li-ion battery is being explored for EV and beyond these days[1]. However, expending the use of Li-based battery to a large electricity storage system for grid support may be more realistic if more abundant earth element could be utilized. One of the fine candidate to replace Li ion in large scale battery facility would be Na ion which is one of the most abundant element in earth´s crust[2] and sea water.

Layered oxides, NaMO2 (M = Cr, Mn, Fe, Co, Ni, and mixture of 2-3 transition metal) show one of the largest capacities among the Na-ion cathode candidates due to their structural simplicity. Particularly, Na(FeMn)O2[3] is of great interest because Fe and Mn are abundant and environmentally benign. Recently, one of the largest capacities was reached with P2-phase Na2/3Fe1/2Mn1/2O2[4]. O3-phase of the same composition, however, could not be prepared because each phase depends on the Na concentration[3].

Here, we report synthesis and direct comparison of electrochemistry between P2- and O3-phase Na2/3Fe1/2Mn1/2O2. The pure phases of P2 and O3 are confirmed by XRDs as shown in figure 1 and we have obtained a similar electrochemical performance in terms of capacity and cyclability for both phases. Our focus is to rationalize electrochemical behavior based on the structural types and Na surrounding environment while keeping the composition of oxide layer the same.

Figure 1. XRD pattern matching of a) P2-Na2/3Fe1/2Mn1/2O2 and b) O3-Na2/3Fe1/2Mn1/2O2.

[1] M. Armand, J.-M. Tarascon, Nature, 451, 652 (2008).

[2] S. R. Taylor, Geochim. Cosmochim. Acta., 28, 1273 (1964).

[3] J. S. Thorne, R. A. Dunlap, M. N. Obrovac, J. Electrochem. Soc., 160, A361 (2013).

[4] N. Yabuuchi, M. Kajiyama, J. Iwatate, H. Nishikawa, S. Hitomi, R. Okuyama, R. Usui, Y. Yamada, S. Komaba, Nature Mater., 11, 512 (2012).
In Situ Gas Analysis - Method Development and Application to Study Cathode Performance in Li-O2 Cells
Authors: Berg Erik J. , Novák Petr
Published: February 2020

New insights into the electrochemical formation of volatile species in Li-O2 cells are provided by combining differential electrochemical mass spectrometry with online pressure analysis. In situ gas analysis during Li-O2 battery cycling is crucial to identify parasitic side-reactions and determine reversibility of the cell. The figure shows the potential and gas evolution profiles of O2, CO2, H2, H2O, CO, DME during the 1st and 3rd galvanostatic charge (0.1 mA/cm2) of a Li-O2 cell (20:80 PTFE:BP2000 carbon, 0.2 M LiTFSI in Diglyme) after a shallow discharge (~5% of total capacity). On the 1st and 3rd discharge, oxygen is consumed at a lower rate (~2.12 and ~2.28e-/O2, respectively, as probed by ΔP(O2)) than expected for Li2O2 formation (2e-/O2), clearly indicating influence of parasitic side-reactions during cycling. On charge, O2 evolves slightly above 3 V initially with a rate expected for Li2O2 oxidation. At 3.2 V, O2 evolution rate gradually drops and CO, H2, H2O appear. At 3.8 V, CO2 evolves possibly as results of oxidation of carbonates, which formed during discharge. Above 4.5 V, DME is observed, which is related to direct electrolyte oxidation. In subsequent cycles, the cell over-potentials increase, the maxima of O2 evolution rate gradually shift to higher potentials, while the gas evolution associated with parasitic side-reactions becomes more pronounced. In our contribution we demonstrate how development and application of in situ gas analysis with high sensitivity provide detailed insights into Li-O2 cell chemistry.

BASF SE is greatfully acknowledged for financial support.
Electrochemical Performance of Lithium-Air Cells with Conductive Polymer-Coated Lithium Anode
Authors: Kim Jae-Hong , Kim Dong-Won
Published: February 2020

Since the non-aqueous Li-air battery was reported in 1996, it has attracted much attention in recent years due to its high theoretical specific energy of 11,000 Wh kg-1. The successful development of rechargeable Li-air batteries is critically dependent on the long-term stability of all battery components. However, the development of rechargeable lithium-air batteries has been hindered by the high reactivity of lithium metal to liquid electrolytes and the occurrence of dendrite growth during charge and discharge cycles. Therefore, protection of lithium metal and the formation of a stable solid electrolyte interphase (SEI) layer on the lithium electrode are very important for developing lithium-air batteries with good capacity retention. NASICON-type lithium conductors and their composites with ionic conducting polymers were applied to protect lithium metal electrode [1,2]. Recently, our group reported that a surface coating of lithium metal with poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol) (PEDOT-co-PEG) was very effective for improving the cycling stability of Li/LiCoO2 cell [3].

In this study, we applied a protective layer comprising bi-conductive polymer, PEDOT-PEG, without adding any inorganic materials for protecting a lithium anode. The conductive polymer coating on the lithium electrode notably improved the cycling performance of the lithium-air batteries. The improvement in cycling stability was attributed to the conductive polymer coating suppressing lithium dendrite growth and the deleterious reaction between the lithium electrode and the electrolyte solution during cycling. The cycling performance of lithium-air cells with conductive polymer-coated lithium metal was evaluated and compared to that of cell with pristine lithium electrode.

References

1. S.Hasegawa, N.Imanishi, T.Zhang, J.Xie, A.Hirano, Y.Takeda, O.Yamamoto, J. Power Sources, 189, 371 (2009)

2. T.Zhang, N.Imanishi, S.Hasegawa, A.Hirano, J. Electrochem. Soc., 155, A965 (2008)

3. I.S.Kang, Y.S.Lee, D.W.Kim, J. Electrochem. Soc., 161, A53 (2014).
Highly Active Nonplatinum Electrodes for Rechargeable Metal-Air Battery
Authors: Nitta Iwao , Nakanishi Shinji , Nishikoori Hidetaka , Iba Hideki
Published: February 2020

Metal-air batteries have attracted much attention as a promising energy storage system because of their extremely high theoretical energy density. It may also offer the attractive opportunity to utilize inexpensive and environmentally friendly materials. However, it is still hard to meet the high demands such as cycle life or energy efficiency required for electrified transportations like EVs, and needed further understanding of battery science as well as many breakthroughs in material design and system integration.

The oxygen reduction reaction (ORR), which proceeds on the air cathode, is believed to be largely responsible for determining the performance of the battery because ORR is intrinsically a demanding reaction due to the sluggish kinetics and slow mass transport process. However, there is still little systematic understanding of what role surface chemistry determines the electron transfer kinetics especially in alkaline media.

In this study, mixed metal oxides such as Perovskites and Spinels were prepared with various synthetic concepts and their structural and electrochemical characteristics were investigated. It was found that some Perovskite catalysts prepared by citric acid method show even superior activity than that of Platinum group metal catalyst (Fig. 1). We attribute this excellent ORR activity of the metal oxide-based electrodes to the intimate contact and the specific interaction between metal oxide catalysts and carbon supports which facilitate the efficient electron transfer to adsorbed intermediate peroxide species. This process consequently leads serial reduction of intermediate species to hydroxide, thus the overall process could be viewed as an apparent 4 electrons reduction reaction. It was also found that the facility of ORR was highly dependent on the choice of B site element in Perovskite and the geometrical design of the air electrode tuned by slurry preparation and coating processes.

The performance of full cell was evaluated with the air cathode consisted of the Perovskite catalyst and carbon support, various anodes such as originally developed metal hydride and the third electrode specifically used for the oxygen evolution reaction. The battery shows a promising rate capability and capacity retention for extensive cycling test.
Molecular Dynamics Simulation on Oxide Ion Conduction of La-Based Perovskite Oxides for SOFCs Electrolyte
Authors: Yoon Mi Young , Jeong Seong Min , Hwang Hae Jin
Published: February 2020

La-based perovskite oxides have various physical and electrical properties by substitution of various elements at A and/or B-sites. Especially, doping of low-valent cation generates oxygen vacancies to maintain charge neutrality, leading to high oxide ion conductivity. Also, B-site is comprised of transition metals such as Co, Mn or Fe, the La-based perovskite oxides become a mixed ionic-electronic conducting material. So, these La-based perovskite oxides can be applied to electrode, electrolyte or interconnect materials of solid oxide fuel cells (SOFCs). Recently, the SOFCs operating temperature is getting lower, much attention has been paid to the La-based perovskite oxides to alternate a conventional electrolyte material, yttria-stabilized zirconia (YSZ). To obtain an optimal La-based perovskite oxide with high oxide ion conductivity, it is very important to understand a correlation between experimental variables such as dopant type or concentration and various factors affecting the electrical conductivity. Therefore, we microscopically analyzed the effects of A-site dopant types and B-site cation types in LaInO3 perovskite oxide with orthorhombic structure on the oxide ion conductivity using molecular dynamics simulation. La0.9A0.1InO2.95 (A=Ca, Sr and Ba) and La0.9Sr0.1MO2.95 (In, Ga and Sc) compositions were modeled. The pair potential used in this study has two parts. One part represents long-range interaction described by Coulombic force. The other part represents short-range interaction by Born-Mayer-Huggins pair potential. The simulation box consisted of a total of 3960 atoms with periodic boundary conditions. Main calculations were carried out for 1.6ns with time step of 1fs after relaxation under NPT ensemble. From the radial distribution function results, it was found that the interionic distance between oxide ion and A-site dopant is important factor determining the ionic conductivity.