bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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).
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.
High Performance Infiltrated Backbones for Cathode-Supported SOFC's
Authors: Gil Vanesa , Hansen Kent Kammer 
Published: February 2020

The concept of using highly ionic conducting backbones with subsequent infiltration of electronically conducting particles has widely been used to develop alternative anode-supported SOFC´s. In this work, the idea was to develop infiltrated backbones as an alternative design based on cathode-supported SOFC. The cathodes are obtained by infiltrating LSM into a sintered either thick (300 μm) yttria stabilized zirconia (YSZ) backbone or a thin YSZ backbone (10-15 μm) integrated onto a thick (300 μm) porous strontium substituted lanthanum manganite (LSM) and YSZ composite.
Fabrication challenges, microstructural characterization and electrochemical testing are discussed. Data on polarization resistance, Rp, are obtained from impedance spectra recorded on quasi-symmetrical cells (YSZ backbones/YSZ/LSM-YSZ (screen printed)). The backbones are infiltrated with LSM and compared to a standard LSM-YSZ screen printed symmetrical cells. Samples with LSM/YSZ composite and YSZ backbones made with graphite+PMMA as pore formers exhibited comparable Rp values to the screen printed LSM/YSZ cathode. This route was chosen as the best to fabricate the cathode supported cells.
SEM micrograph of a cathode supported cell with infiltrated LSM nanoparticles is shown in Fig. 1.

Figure 1. Cross section of LSM infiltrated cathode supported cell.
Short Stack Performance Using Lower Temperature GDC-Based SOFC
Authors: Yoon Hee Sung , Blackburn Bryan M. , Wachsman Eric D. 
Published: February 2020

Recently, the University of Maryland Energy Research Center and Redox Power Systems LLC developed a GDC electrolyte based solid oxide fuel cell (SOFC) for lower temperature operation using conventional ceramic processing. The fabrication process was integrated with tape casting, screen printing, coating, etc., yielding a cell of 10 cm x 10 cm size and an active area of about 80 cm2.
Initial results for single cell tests running on hydrogen and air at 650 oC included an open circuit voltage (OCV) of 0.85 V and a power of over 48 W at over 80 A. At an operating voltage of 0.7 V, the single cell power was about 35 W. For a two cell short stack, the initial results under similar conditions showed an OCV of 1.5 V and a peak power of more than 70 Watts at 650 °C.