bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Structure, and Properties of the New Intercalation Cathode Material MoO2.8F0.2
Authors: Incorvati Jared T , Wustrow Allison , Poeppelmeier Kenneth
Published: February 2020

The widespread adoption of multivalent batteries is hampered by the lack of stable, reliable, high voltage cathodes that can reversibly intercalate divalent cations. In lithium-based systems, molybdenum trioxide has been studied for several years as a high capacity cathode material. Although its voltage is lower than other systems, e.g. V2O5, it has advantages including crystallographic stability on cycling. A key issue that is believed to limit its performance is that, as a d0 metal oxide, it has limited electronic conductivity at top of charge.1 In this poster we will be discussing the role of fluoride incorporation into the layered charged cathode MoO3 and its effect on the materials physical properties. Utilizing synthetic methodologies developed in our lab we have studied the fluoride solubility in the host material as a way to induce electronic conductivity across the whole range of use. We have shown that the maximum fluoride incorporation in the material yields a stoichiometry of MoO2.8F0.2. Incorporation above this value results in isolation of the perovskite phase MoO2.6F0.4. We have evaluated the material using multiple intercalating cations and compared it to the undoped parent material. While the electrochemical activity of the material using a lithium-based electrolyte is similar, remarkable differences have been observed when Mg is used as the cation. While the undoped material has little or no activity, the fluorinated materials shows excellent cycleability and structural reversibility.2

References:

(1) Spahr, M. E.; Novák, P.; Haas, O.; Nesper, R., Electrochemical insertion of lithium, sodium, and magnesium in molybdenum(VI) oxide. J. Power Sources
1995, 54, 346-351.

(2) Incorvati, J. T.; Wan, L. F.; Key, B.; Zhou, D.; Liao, C.; Fuoco, L.; Holland, M.; Wang, H.; Prendergast, D.; Poeppelmeier, K. R.; Vaughey, J. T., Reversible Magnesium Intercalation into a Layered Oxyfluoride Cathode. Chemistry of Materials
2016, 28, 17-20.

Figure 1
How New Advancements Enable a Position Change in the Science of Magnesium Batteries
Authors: Mohtadi Rana , Tutusaus Oscar , Arthur Timothy S. , Mizuno Fuminori
Published: February 2020

Driven by the need to access higher energy densities beyond those offered by Li-ion batteries, rechargeable Mg batteries have been receiving increased interests. Although Mg metal is not competitive with Li metal on both specific capacity (2205 mAh g-1 vs. 3862 mAh g-1 for lithium) and redox potential levels (-2.3 V compared to -3.0 V for Li vs. NHE), it was found to be non-dendritic. In addition, Mg metal has a high volumetric capacity (3833 vs. 2046 mAh cm-3 for Li), and offers an opportunity for battery cost reductions owing its abundance in the earth crust (5th most abundant element).  However, several technical challenges that hamper realizing practical rechargeable Mg batteries are currently present.  For example, the absence of robust and practical high voltage/high capacity cathodes currently limits the energy density which could be harnessed using these systems.[1]  Another major hurdle is caused by the type of electrolytes currently used in Mg batteries. At its very core, is the limitation induced by the incompatibility of Mg metal with simple ionic salts and non-ethereal solvents. This has limited the working electrolytes options to a handful of complex halogen systems which are corrosive.  We have been pioneering the development of a new family of electrolytes based on a novel bottom-up design strategy to create highly performing simple type highly compatible Mg salts.  Herein, we will explain our design concepts that guided the development of a new paradigm using boron-hydrogen salts and resulted in demonstrating the only ionic simple-type salts known to date that are highly compatible with Mg metal.[2,3]

References

[1] a) R. Mohtadi, F. Mizuno  Beilstein J. Nanotechnol.
2014, 5, 1291–1311, b) H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci. 2013, 6, 2265-2279.

[2] a)  R. Mohtadi, M. Matsui, T. S. Arthur, S.-J. Hwang, Angew. Chem. Int. Ed.
2012, 51, 9780 –9783;  b) T. J. Carter, R. Mohtadi, T. S. Arthur, F. Mizuno, R. Zhang, S. Shirai, J. W. Kampf, Angew. Chem. Int. Ed.
2014, 53, 3173-3177, c) O. Tutusaus, R. Mohtadi, ChemElectroChem.
2014DOI: 10.1002/celc.201402207;

[3] O. Tutusaus, R. Mohtadi, T. Arthur. F. Mizuno, Angew. Chem. Int. Ed.
2015, DOI: 10.1002/anie.201412202R3.
Crosslinked Gel Polymer Electrolytes with Different Li Salts for Electrochromic Cells
Authors: Han Taeyeong , Kim Seokwoo , Lee Hoogil , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

The use of electrochromic windows to control heating and cooling loads in buildings and automobiles have attracted a lot of attention as a new and emerging strategy towards energy saving and energy storage to combat global warming and the energy crisis. The types of electrolyte salts employed in an electrochromic device is of great significance to the charge transfer which are in the form of ions between the electrodes. Thus, the electrolyte salt must be viewed as inert component of the electrochromic cell and it should be stable towards the cathode and anode. Hence, we conducted a comprehensive studies based on experiments on the effects of different salts in gel polymer electrolytes on the performance of electrochromic cells consisting of WO3/ITO as the working electrode and NiO/ITO as the counter electrode. Three different salts, 1M LiClO4, 1M LiFSI and 1M LiTFSI in propylene carbonate(PC)/polyethylene glycol diacrylate (PEGDA, Mn: 575) (7/3, v/v) were used in this study. Their ionic conductivities as well as the color changing behavior in the electrochromic cell were investigated.

Acknowledgements

This work was supported by the *Energy Technology Program  of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20142010102980)

Figure 1
Ageing of Commercial 18650 Batteries Used in Tesla Model S Electric Vehicles
Authors: Uitz Marlena , Sternad Michael , Taeubert Corina , Traußnig Thomas , Hennige Volker , Wilkening Martin
Published: February 2020

Li-ion batteries are attractive energy storage devices for years to come. They benefit from a high specific capacity combined with outstanding cyclability. In order to advance in conventional lithium-ion technology it is necessary to develop new materials and to improve existing concepts. In particular, the latter includes ageing studies on, e.g., commercially available batteries. Such studies help predict the lifetime of the batteries and assist in identifying the main failure mechanisms connected to lithium plating, passivating surface films, co-intercalation or dissolution of metal ions, for example.

In the present study commercial 18650 lithium-ion battery cells were used to perform fundamental cycle and calendar ageing studies. For this purpose systematic electro­chemical tests were carried out at three different temperatures, viz. – 25 °C, 40 °C and 60 °C. The cells were charged and discharged via galvanostatic cycling at different C rates ranging from 0.3 C to 1 C. For comparison, calendar ageing was electrochemically monitored at four different SOCs (100 %, 80 %, 50 % and 20 %). After the various aging steps the capacity fade and the increase in AC and DC impedance was determined.

It turned out that temperature has little effect on calendar ageing; the capacity fade (5 % at most) increases with increasing SOC. In contrast to this behavior, during cycle ageing temperature has a much larger effect on capacity fade and DC impedances. As an example, after 500 cycles at 25 °C (or 40 °C) the capacity fade is approximately 12 % of the initial value while at 60 °C the fade has reached already 22 %. DC impedances measured revealed the same trend. First post mortem analyses indicate that the ageing effects observed might be related to changes of the solid electrolyte interphase. Hence, the changes in electrochemical performance were correlated with the thickness and composition of the SEI formed. In particular, we quantitatively measured the formation of LiF via ion exchange chromatography. Interestingly, there is a clear interrelation between fluoride quantity in the SEI and DC impedance growth.
Design of Composite Electrodes with Anion-Absorbing Active Materials
Authors: Thomas-Alyea Karen E. , Aryanpour Masoud
Published: February 2020

Organic radical polymers [1] and conjugated polymers provide exceptionally high rate capability when used as cathode materials for lithium-ion batteries.  Upon charge (oxidation), these materials absorb anions from the electrolyte.  In contrast, traditional inorganic cathode materials release lithium cations into the electrolyte during charge.  All known negative electrode materials for lithium-ion batteries absorb lithium cations during charge.  If a lithium-absorbing negative electrode is paired with a lithium-releasing positive electrode, then there is no net change in the salt content of the electrolyte (although there will be gradients in salt composition as lithium ions are transported from the anode to the cathode).  However, salt content will decrease during charge of a cell with lithium-absorbing negative electrode and anion-absorbing positive electrode. 

Most experimental results published to date [1] have used thin, highly porous cathodes in small flooded laboratory cells.  Such cells have a large excess of electrolyte, so the effects of salt consumption have not been strongly evident.  However, many important applications, such as electric vehicles and portable power, highly value both volumetric energy density and fast charge capability.  These applications also want to minimize cell resistance, so the electrolyte composition is selected to maximize conductivity.  Typical carbonate electrolytes show a maximum in conductivity between 1.0 and 1.1 M concentration of LiPF6 salt.   In a conventional high-energy-density cell design, the salt needed for charging the organic-radical-polymer positive electrode would exceed the total salt content of such a typical electrolyte in the cell.  Some [2,3] have explored composites of anion-absorbing active materials (eg polypyrrole or PTMA) with lithium-iron phosphate.  However, even if the anion-absorbing material is limited to 10 volume% of the positive electrode, it will cause the overall cell salt content to decrease by > 0.6 M in practical high-energy cell designs. 

Full-cell-sandwich simulations [4] can evaluate the impact of electrode design on the salt concentration distribution in the battery.  Here we use a model that includes a composite positive electrode containing both inorganic lithium-releasing active material and organic anion-absorbing active material.  The model is used to evaluate design tradeoffs for maximizing volumetric energy density.

References

[1] K. Oyaizu and H. Nishide, Polyradicals in Batteries.  Encyclopedia of Radicals in Chemistry, Biology, and Materials, John Wiley & Sons Ltd: 2012, DOI 10.1002/9780470971253.rad083.

[2] A. Vlad, N. Singh, J. Rolland, S. Melinte, P. M. Ajayan, and J. F. Gohy, Scientific Reports 2014, DOI 10.1038/srep04315.

[3] Y.H. Huang and J. B. Goodenough, Chem. Mater. 2008, vol. 20#23 p. 7237.

[4] T. Fuller, C. M. Doyle, and J. Newman, J. Electrochem. Soc. 1994 vol. 141 p. 1; K. E. Thomas-Alyea, J. Newman, G. Chen, and T. J. Richardson, J. Electrochem. Soc. 2004 vol. 151 p. A509.
Zinc Pyridinedicarboxylate Micro-Nanostructures: Novel Anode Materials for Lithium-Ion Batteries with Excellent Cycling Performance
Authors: Fei Hai Long
Published: February 2020

It is important to discover new, cheap and environmental friendly coordination polymer electrode materials for lithium-ion batteries. Zinc 2,6-pyridilinedicarboxylate particles show better cycling stability and higher discharge capacity than 2,5-pyridilinedicarboxylate micro-platelets when they are firstly tested as anode materials for lithium-ion batteries. The former can steadily cycle at current densities of 750, 1000 and 2000 mA g-1. It is also stable in multiple insertion/extraction processes at current densities of 750, 1500, 2000, 2500, 3000, and 750 mA g-1, and the capacity retention is 77.9% after 60 cycles. While the latter is apt to show good cycling performance at smaller discharge current density.
High Electrochemical Performance of Rose Flower like NiCO2O4 with Hierachically Porous Structure for Lithium-Ion Battery
Authors: Xu Jing , Su Dawei , Wang Guoxiu
Published: February 2020

Hybrid nanostructured transition metal oxides have attracted great attention as high-performance electrode materials for next-generation lithium-ion batteries. In this work, novel porous NiCo2O4 nanoparticles are synthesized by a solvothermal method using poly (vinylpyrolidone) (PVP) as the structure-directing agent followed by a simple thermal annealing treatment. Through the XRD, FESEM, TEM, and N2 sorption analyses, it has been found that the as-prepared NiCo2O4 nanoparticles show hierarchical China rose flower-like architecture constituted by 2D hierarchically porous nanosheets. The 2D porous nanosheets provide sufficient void space generated during thermal annealing treatment, benefiting electrolyte penetration and fast electron transfer. The porous structure also can tolerate the volume variation upon prolonged charge / discharge cycling. Therefore, when the as-prepared NiCo2O4 nanoparticles are used as anode materials for the Li-ion batteries, they exhibit high capacity, remarkable capacity retention at increased current densities, and outstanding cycling stability (4 % loss after 100 cycles at 1000 mA g-1).

Figure 1
In Situ Studies of Oxide-Electrolyte Interface Reactivity in Lithium-Ion Batteries
Authors: Chen Xiao , Buchholz Donald Bruce , Stan Liliana , Feng Zhenxing , Fister Timothy T , Fenter Paul , Bedzyk Michael J.
Published: February 2020

Li-ion batteries (LIBs) have been widely used in the past 2 decades, due to their higher energy density and cycling ability, typically using carbon as an anode and layered LiCoO2 as a cathode. The spinel, LiMn2O4 (LMO) is cheaper, safer, and more environmental friendly compared with widely-used LiCoO2 cathodes. However, LMO is known to lose capacity during cycling, ultimately due to disproportionation reactions of Mn3+ transforming to Mn2+ and Mn4+, and the subsequent dissolution of Mn2+ into the electrolyte. Yet our understanding of this process remains rudimentary, and we expect that it can be effectively addressed through interfacial modification (e.g., coatings). This work specifically focuses on developing and using a well-defined model system to observe these interfacial instabilities, and to develop suitable approaches to prevent it.

Recently, we have successfully grown high quality epitaxial LMO film on multiple substrates by pulsed laser deposition (PLD). Since LMO film itself is a poor electrical conductor, we have designed systems with built-in current collectors that maintains the LMO-substrate epitaxy. Multiple approaches have been investigated to make the whole system conductive and suitable for cycling: using conductive substrates, a conductive buffer layer, or a conductive surface coating. Conductive substrate is the most straightforward method. High quality epitaxial LMO film has been grown on Nb:STO. For the conductive buffer layer approach, we have tried many possible material including TiN, Al:ZnO, ITO, SrRuO3. It turns out that ITO and SrRuO3 are robust and enable oriented LMO deposition. Graphene was adopted as conductive surface coating. We have successfully transferred graphene onto the surface of LMO film using an anhydrous method.

We focus on the in situ real-time surface X-ray studies of well orientated LMO films in the standard lithium ion battery electrolytes (e.g., LiPF6 in EC/DMC). Using the high quality model films grown by PLD, we have probed the mobility of ions and interfacial atomic- and molecular- structures across the electrolyte/electrode interface, including the surface/interface structure changes and reconstruction (using XRR and CTR), individual processes of cation adsorption (resonant XRR/CTR), insertion/extraction.
Titanium Phosphite Ti2(HPO3)3, a New Negative Electrode Material for Lithium Ion Batteries
Authors: Lallaoui Abdelfettah , Edfouf Zineb , Benabdallah Omar , Abd-lefdil Mohammed , Saadoune Ismael , Cherkaoui El Moursli Fouzia
Published: February 2020

Research in the area of solids open-framework metal phosphates, has been experiencing considerable growth over the past two decades. Since 1980s, a series of transition metal phosphates with three-dimensional structure have been investigated. More recently, it has been revealed that the phosphite group, could also be of great interest, because of its tendency to form new solids open framework structure.

In the literature, mixed-phosphite metal compounds have been widely synthesized with a variety of cations going from alkali metals to group IIIA of the periodic table. Some rare earth based phosphites have been also isolated. However, to the best of our knowledge, no compound with titanium and  phosphite group has been reported. This compound has an interesting structure allowing it to be used as insertion material for electrodes of Li-ion batteries, while only phosphates and phosphides compounds have been used as electrode materials.    

Recently, two inorganic phosphite materials were tested as electrodes for energy storage systems and have shown very small specific capacities toward lithium insertion [1,2]. Besides, both works dealt with the use of phosphite based-compound as positive electrode.

In this study, we are presenting a new titanium phosphite compound used as negative electrode material for lithium ion batteries. Ti2(HPO3)3 has been prepared under hydrothermal conditions and autogenous pressure. The structure of titanium phosphite with the determined crystallographic formula Ti2(HPO3)3 was solved in hexagonal system in centrosymmetric P63/m space group from single crystal diffraction data. The structure was solved by the direct method using, refined by full matrix least square.It has a three dimensional structure with tunnels along a- and b-axes (see figure). This is exactly what interests us to test it as an insertion electrode material.

This compound displays a high thermal stability limit showed by TGA analysis. Structural and chemical characterization have been realized by XRD, IR and Raman spectroscopies respectively. Electrochemical analyses were done by galvanostatic cycling and cyclic voltammetry. On the initial discharge of cell, the Ti2(HPO3)3 electrode delivers a capacity of 740 mAh/g.

In the aim of enhancing the electrochemical performances, Ti2(HPO3)3/graphene composite was also prepared via hydrothermal route. Results of both compounds will be presented and compared in this present publication.

[1] U. Chung, J.L. Mesa, J.L. Pizarro, I. de Meatza, M. Bengoechea, J. Rodríguez Fernandez, M. I. Arriortua, and T. Rojo, J. Chem. Mater. 23 (2011) 4317-4330.

[2] H. Yaghoobnejad Asl, K. Ghosh, M. P. Vidal Meza, A. Choudhurya, J. The Royal Society of Chemistry. (2013),  00, 1-3.

Figure 1
Co3V2O8 Sponge Network Morphology Derived from Metal-Organic Framework As an Excellent Lithium Storage Anode Material
Authors: Sambandam Balaji , Soundharrajan Vaiyapuri , Song Jinju , Kim Sungjin , Jo Jeonggeun , Kim Seokhun , Lee Seulgi , Mathew Vinod , Kim Jaekook
Published: February 2020

Metal-organic framework (MOF) based synthesis of battery electrodes has presently become a hot topic of significant research interest. Considering the complications to prepare Co3V2O8 due to the criticality of its stoichiometric composition, we report here by a simple MOF formation by solvothermal technique followed by air annealing to synthesize Co3V2O8 for use as potential anodes for lithium battery applications. Structrual investigations by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution electron microscopy, and surface area studies revealed that the phase pure Co3V2O8 nanoparticles are inter connected to form a sponge-like morphology with porous properties. Electrochemical measurements exposed the excellent lithium storage (~ 1000 mAhg-1 at 200 mAg-1) and retention properties (500 mAhg-1 at 1000 mAg-1 after 700 cycles) of the prepared Co3V2O8 electrode. A notable rate performance of 430 mAhg-1 at 3200 mAg-1 was also observed and  ex-situ analysis confirmed the morphological and structural stability of this material after long cycles performance. These  results validate that the unique nanostructured morphology arising from the use of the ordered array of MOF networks is favorable for improving the cyclability and rate capability in battery electrodes. The synthetic strategy presented herein may provide solutions to develop phase pure mixed metal oxides for high performance electrodes for useful energy storage applications.

Figure 1
CNT Branching on the 3D Nitrogen-Doped Graphene Architecture for Lithium Ion Battery
Authors: Park Beum Jin , Park Ho Seok
Published: February 2020

The hybridization of 1D CNT with 3D graphene structure has recently attracted attention owing to their large specific surface area, high electronic conductivity, and structural integrity. These features of the hierarchical architectures can provide synergic affect on the energy storage such as supercapacitors, fuel cells and lithium-ion batteries. In addition, the performance has been further improved by doping with different heteroatoms like sulphur, boron, phosphorous and nitrogen because they can play a vital role in changing the local electronic density leading to improved electronic conductivity.

 In this work, we synthesize 3D nitrogen (N)-doped reduced graphene oxide (rGO) branched by CNT for applications into lithium ion batteries. The hierarchical architecture consisting of the CNT branching on 3D N-doped rGO was characterized by SEM and TEM images. Iron oxide nanoparticles acted as the catalyst for the growth of CNT as well as active materials for lithium storage. The crystalline structure of iron oxide nanoparticles and restacking inhibition of rGO were confirmed by the XRD analysis. The BET data indicate the presence of mesoporous structure with average pore diameter of 21 nm with 400 m2/g surface area.  The XPS data identified the presence, composition, and bonding configuration of carbon, iron, nitrogen and oxygen. The electrochemical properties were characterized by cyclic voltametry, impedance spectroscopy, and galvanic charge/discharge curve for lithium ion battery application.
Thermophysical Properties of Positive Electrode of Lithium-Ion Batteries
Authors: Saito Yoshiyasu , Kobayashi Hironori
Published: February 2020

Thermal simulation is effective to estimate safety of lithium-ion batteries.  For obtain reliable results by simulation, precise values are necessary for thermophysical properties such as specific heat capacity and thermal conductivity of the component materials of the batteries in wide temperature range.  For the active electrode materials, since the lithium content varies during charge and discharge, dependency on state of charge (SOC) should also be considered.  In this study, specific heat capacities and thermal conductivities of some positive electrode materials such as Li
x
Ni0.85Co0.05Al0.10 (NCA), Li
x
Ni1/3Mn1/3Co1/3O2 (NMC) and so on are studied as functions of temperature and lithium content.  In addition, influence of electrode structure such as porosity is discussed for the thermal conductivity of the positive electrode.

The sample electrodes were prepared by coating the mixture of the active electrode material with carbon black and PVDF binder on both side of Al current collector of which thickness was 0.020 mm.  The porosity and the thickness of the electrode were controlled by pressing. 

The specific heat capacities of the samples were measured by the scanning method using differential scanning calorimeter.  The thermal diffusivities of the electrode sheet were measured by the distance-variation method with a fixed modulation frequency in the periodic heating technique which is adequate for film-like samples.  Then, the thermal conductivities were evaluated from the products of the specific heat capacities, the thermal diffusivities, and the bulk densities.

Additivity was confirmed for the specific heat capacity of the electrode sheet.  The sample containing more lithium showed larger specific heat capacity except for crystal phase transition region.  For the thermal conductivities, higher value was obtained from denser samples if the mixing ratio of active material, carbon black and PVDF was unity.
Battery Materials Exploration with Neutrons and Synchrotron X-Rays
Authors: Ren Yang , Sun Chenn-Jun , An Ke , Chen Zonghai , Xiao Xianghui , Aoun Bachir , Amine Khalil
Published: February 2020

The increasing demands for alternative energy sources and energy storage systems have created a fast growing global market for rechargeable batteries. Extensive research activities are in progress worldwide aiming to develop reliable, cheap, environmentally benign and high-performance materials for advanced rechargeable batteries. Fundamental materials exploration is critical to achieve the next generation battery technology. X-rays and neutrons interact with matter in different ways, thus are frequently used as complementary tools for studying materials at the electronic, atomic and molecular levels. We have been utilizing synchrotron x-ray and neutron techniques to investigate a large variety of materials for energy applications. In this poster, we will present our recent results on both in-situ and ex-situ studies of battery materials using various neutrons and synchrotron x-ray techniques, including diffraction, imaging and spectroscopy. We will also discuss the challenges in battery materials research, and our future experimental approaches and computational modeling. (Use of the Advanced Photon Source was supported by the U.S. DOE Office of Science under Contract No. DE-AC02-06CH11357.)
In Situ Characterization of Gassing Processes in Lithium-Ion Batteries By Dems-Deirs
Authors: Berkes Balázs B. , Sommer Heino , Brezesinski Torsten , Janek Jürgen
Published: February 2020

Gas evolution strongly affects the functioning of state of the art lithium ion batteries. On the one hand, it is the natural concomitant of SEI formation; on the other hand, because of the demand for high terminal voltages, it is the consequence of electrolyte or electrode material oxidation. This happens on the expense of the efficiency. Furthermore, the presence of gases in the cell raises safety problems.

Both the above mentioned gas formation processes are important to understand. First, to be able to develop novel electrolyte mixtures or tailor electrolyte additives that form a stable SEI. Second, to optimize the surface and/or structure of the cathode materials to influence their bulk oxidative properties upon delithiation and electrocatalytic activities.

Herein, we present results on the in situ gas analysis by means of differential electrochemical mass spectrometry and infrared spectroscopy (DEMS-DEIRS) of various battery systems. We analyse the SEI formation on different anode materials and the influence of various electrolyte additives. The impact of temperature and constant voltage/OCV periods on the first charge cycle (so-called formation process) is investigated. Their effect on both the gassing and electrolyte salt decomposition is described.

The stability problem of the most common electrolytes at high voltages is discussed. These are achieved either with NMC (LiNixMnyCozO2) type materials or with high voltage spinels (LiNi0.5Mn1.5O4). Beyond the decomposition of the electrolyte, oxygen evolution is the crucial factor at high cathode potentials. This effect is particularly apparent for overlithiated and high Ni content materials that will be presented as well. Monitoring gassing over 20 cycles reveals interesting changes in its characteristic being only recognizable in long term tests. We demonstrate the importance of potentiodynamic cycling tests beneath the traditional galvanostatic ones with DEMS-DEIRS in the exploration of reaction mechanisms. Pressure measurements complete the analysis in terms of validation of gas amounts and supplement them with three-electrode long term investigations.
Dopamine As an Electrolyte Additive for Lithium Secondary Batteries
Authors: Lee Hoogil , Han Taeyeong , Kim Seokwoo , Jin Dahee , Kim Hee Joong , Rho Jin Woo , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

Polydopamine is gaining much interest in lithium secondary batteries (LSBs) due to its ability to enhance the electrochemical characteristics of the various LSB systems. However, the commercialization of polydopamine is being delayed due to long production time. Nevertheless, recent studies have showed that polydopamine can be formed during galvanostatic charge and discharge of unit cells with dopamine. Hence we adopt this methodology to study the effects of dopamine as an electrolyte additive on the electrochemical performance of LSBs. The effect of the dopamine additive is characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The cycle performance of coin cells containing dopamine in the electrolyte at different temperatures are examined by changing cut-off voltages together.

The coin cells having 0.1 wt.% of dopamine exhibited an enhanced cycle performance at both high voltage (3.0~4.5V vs. Li/Li+, 25oC, C/2 rate) and elevated temperature (3.0~4.3V vs. Li/Li+, 55oC, C/2 rate). The improvement in the cycling performance is attributed to the suppression of transition metal dissolution in the cathode as well as the decomposition of both solvent and salt in the electrolyte due to the formation of the polydopamine on the surface of the cathode during the galvanostatic charge and discharge.

 Acknowledgements

This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977) and by the Sebang Global Battery.

 Refernces

1. M.-H. Ryou, Y. M. Lee, J. K. Park, and J. W. Choi, Advanced Materials 2011, 23, 3066-3070.

2. Y. Lee, M.-H. Ryou, M. Seo, J. W. Choi, Y. M. Lee, Electrochimica Acta 2013, 113, 433–438.

3. T. Lee, Y. Lee, M.-H. Ryou, Y. M. Lee, RSC Advances 2015, 5, 39392-39398

4. K. Kang, S. Lee, R. Kim, I. S. Choi, and Y. Nam, Angewandte Chemie International Edition 2012, 51, 13101 –13104.
Effect of Electrolyte Amount on Electrochemical Properties of Coin-Type Lithium-Ion Cells
Authors: Han Taeyeong , Lee Hoogil , Kim Seokwoo , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

Most of electrochemical data in published papers are obtained from coin-type cells, which consist of small disc-type cathode/anode pairs, a little larger separator, and excess liquid electrolyte. In particular, comparing to commercial LIB cells, it should be clearly understood that too much electrolyte can give a positive or negative effect on electrochemical properties. However, there have been few reports on this issue, and they are not fully investigated.

Thus, we try to figure out this point with coin-type cells. The amounts of liquid electrolyte are controlled by measuring the coin cell mass difference before and after assembly. Three different coin cells are evaluated to compare the initial discharge capacity and coulombic efficiency, electrochemical impedance, c-rate capability, and cycle life at room temperature. And then, the operating or storing temperatures are also changed. Finally, some electrolyte additives are also investigated under the different liquid electrolyte amounts in coin cells.

Acknowledgements

This work was supported by the Energy Technology Program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20142010102980)
Ionic Structure and Physical Properties of Fluorinated Alkyl-Phosphate Solutions Dissolving Lithium Salts
Authors: Todorov Yanko , Fujii Kenta , Aoki Masahiro , Mimura Hideyuki , Yoshimoto Nobuko , Morita Masayuki
Published: February 2020

Fluorinated alkylphosphates (FAPs) have been examined as nonflammable organic solvents for lithium-ion battery (LIB) electrolytes. Some research groups have already reported on the contribution of FAPs as either co-solvents or additives to the improvements in the safety of the battery system. There have also been publications concerning FAPs that can improve the battery performance under high-voltage operation by their use as the co-solvents in the electrolyte system. The characteristics of the electrolyte system are strongly dependent on the physico-chemical properties of the electrolyte solution. In the present paper, we have examined several combinations of FAP as the solvent and lithium salts as the electrolyte solute, and investigated the relationship among the solution composition, ionic structure and such physico-chemical properties as viscosity and ionic conductivity.

As a typical FAP, tris-2,2,2-trifluoroethyl-phosphate (TFEP) has high solubility toward conventional lithium salts, LiPF6, LiBF4, and Li(CF3SO2)2N (LiTFSA). The order of the ionic conductivity of the TFEP solution was LiTFSA>=LiPF6>LiBF4 over a wide temperature range. Concentration dependence of Walden’s product (the product of ionic conductivity and viscosity) of the electrolyte solution suggested that the degree of ionic association or ion-pair formation depends on the anionic species in the lithium salt. The IR/Raman spectra of the electrolyte solutions also showed that the ionic structure including the solvent coordination (solvation) of Li+ is different among the electrolyte composition. The solvation number of Li+ in TFEP was determined by the IR/Raman spectra, and was found to change from 2 to 4, depending on the anion. The DFT (Density Functional Theory) calculation gave the stabilized configuration of the solvated Li+ in TFEP that also depends on the anionic species.

An FAP with smaller number of F-atom, bis(2,2,2-trifluoroethy)ethyl phosphate (BTFE), and triethylphosphate (TEP: no F-atom) for comparison were also examined as the solvent of the electrolyte solution. The number of F-atom in the solvent much influenced the solubility of the lithium salt, and hence the conductivity behavior of the resulting electrolyte solution. In conclusion, the molecular structure of FAP influences the ionic structure of the electrolyte solution, which contributes to the electrochemical stability of the electrolyte system in LIB.
Gamma'-V2O5 : A New Sodium-Insertion Material Operating at 3.3 V Vs. Na+/Na
Authors: Baddour-Hadjean Rita , Safrany-Renard Marianne , Pereira-Ramos Jean-Pierre , Muller-Bouvet Diane
Published: February 2020

A new sodium insertion compound, γ'-V2O5, was prepared by the chemical oxidation of γ-LiV2O5 phase using NO2BF4 as oxidizing agent. One sodium ion per mole of γ'-V2O5 can be inserted in γ'-V2O5 involving a high V5 +/V4 + redox potential of 3.5 V vs. Na+/Na. A fully reversible capacity of 145 mAh g− 1 was obtained at C/60, at 50°C (figure 1). The γ'-V2O5 electrode can deliver a high discharge capacity of 125 mAh g− 1 at C/20 rate at 50°C, stable over 50 cycles. An excellent retention capacity is also demonstrated over 90 cycles at RT: capacities in the range 60-80 mAh. g-1 in the C/5-C/20 range against 100-125 mAh g-1 at 50°C were recovered. A discharge capacity of 80 mAh g− 1 was still available after 90 cycles at C/20 rate. A two phases mechanism involving the γ'-V2O5 / γ-NaV2O5 system was evidenced from X-ray diffraction and Raman spectroscopy measurements. The structural features of the fully sodiated γ-NaV2O5 phase, with an unusual expansion along the c axis (+2 Å/ γ'-V2O5) were solved (inset in figure 1). These results revealed that the γ'-V2O5 forms a new competitive cathode for the reversible intercalation of sodium ions.

Figure 1
Na-Ion Batteries Based on Na-Rich Layered Oxyde and Optimised Hard Carbon: An Study of the Electrode/Electrolyte Interphase
Authors: Santos Pena Jesus , Montigny Benedicte , Autret Cecile
Published: February 2020

Sodium ion batteries (NIB) represent nowadays one of the most promising « beyond Li » technologies. However, and according to recent reviews [1], the development of a true market based on NIB strongly depends on optimizing positive/negative electrode couples delivering high potentials and with a suitable electrolyte.

Research carried out in the PCM2E/GREMAN laboratories is focused on the synthesis and electrochemical characterization of positive electrodes based on new materials ascribed to the Na-rich oxide family, not containing expensive and toxic ions as cobalt.  In a first time, sodium half-cells with very nice capacities, close to 140 mAh/g, have been successfully prepared in our laboratories. In order to ensure capacity retention, we have also studied different electrolytes by measuring their impact on the electrode/electrolyte interphase. Spectroscopic techniques as XPS and EIS are helpful for this goal. More recently, our laboratories are focusing on the building of full cells containing such oxides against optimized hard carbon-based composites as negative electrode, with increased conductivity.

In this presentation we will show the first results on these full NIBs and analyze their cycling properties by the use of different physico-chemical and electrochemical techniques.

 [1]
Structure Changes of P2 Layered Material Via in Situ XRD Studies during Desodiation/Sodiation
Authors: Jung Young Hwa , Christiansen Ane Sælland , Johnsen Rune E. , Norby Poul , Kim Do Kyung
Published: February 2020

One of the promising positive electrode materials for sodium ion batteries (SIB) is sodium layered oxides (NaxMO2) due to its high capacity, fast ionic diffusion, and simple synthetic process. Unlike lithium ion batteries, in which O3-layered lithium compounds showed better performance and therefore have now been successfully commercialized, P2-layered compounds have been reported for better cyclability and structural stability during electrochemical reactions than O3-structure in SIBs. The phase transformations of layered compounds during electrochemical reactions are a pivotal feature for understanding the relationship between layered structures and electrochemical properties. Therefore, systematic structural study of P2-layered compounds for SIB is highly needed. In this study, a combination of in situ diffraction study using a capillary-based microbattery cell and ex situ X-ray absorption spectroscopy were utilized to reveal the phase transition mechanism for the ternary transition metal system (Fe–Mn–Co) with P2 stacking. The in situ XRD showed structural change from P2 to O2 in P2–Na0.7Fe0.4Mn0.4Co0.2O2 compound at the voltage plateau above 4.1 V during desodiation and subsequent restoration to P2 structure upon sodiation. At fully charged state, volumetric contraction of the lattice was observed, which was due to the significant decrease in the lattice parameter c of the O2 structure. This study on the electrochemical behavior of each transition metal in P2–Na0.7Fe0.4Mn0.4Co0.2O2 via X-ray absorption spectroscopy indicate that all transition metals are contributing to the reduction/oxidation process.
Intercalation State of PF6
- in Graphitic Carbon for High Potential Dual Carbon Battery
Authors: Fukuda Taro , Ishihara Tatsumi , Inda Keisuke , Ida Shintaro , Akbay Taner
Published: February 2020

Recently, strong demand has arisen for batteries with large capacities to support various types of mobile equipment. Li-ion batteries (LIBs) have been widely used for this purpose. In Li ion battery, intercalation of Li is only used but anion in electrolyte is not used for storage of electric energy. However, there is high interest on PF6
- intercalation into graphitic carbon and by using intercalation of Li+ and PF6
- into graphitic carbon for anode and cathode, respectively, electric energy can be storage.  This battery is called dual carbon battery, however, electronic state of PF6
- into graphitic carbon is not thoroughly understood up to now.  In this study, electrochemical intercalation reaction of PF6
- into graphotic carbon was studied by using solid state NMR and also XPS. Quantum calculation is also applied for estimating the stable structure of PF6
- sandwiched between graphitic sheets.

During electrochemical intercalation of PF6
-, reduction of PF6
- will be occurred and so XPS measurement was performed to estimate the change of oxidation state.  In spite of several oxidation number, there is no change in valence state of P5+, however, XPS spectra of F- shifter to high binding energy suggesting that reduction of F- occurred during intercalation. NMR measurement of F and P also suggested that chemical shift was mainly observed on F peak but no change in P peak. In addition, coupling constant of F is significantly changed suggesting that the structure of PF6 may be changed during intercalation of PF6. From quantum calculation of stable structure of PF6 in graphene sheet, tilting structure is the most stable structure which is well agreed with the results of NMR measurement.  Diffusivity of PF6 in graphitic carbon is also estimated and the observed diffusion constant is almost the same with that of Li in carbon and this is well explained the superior rate property of dual carbon battery.
In-Operando X-Ray Diffraction of Na-Ion Batteries
Authors: Hall Nikita , Lain Michael J , Kendrick Emma , Gruar Robert , Beattie Shane D
Published: February 2020

Future demand for lithium-ion batteries is predicted to increase continuously due to their use in portable electronic devices and larger-scale energy storage, such as hybrid electric vehicles and static energy storage systems. Sodium is ubiquitous and significantly cheaper than lithium.  Recent advances in sodium-ion battery technology has achieved promising results, with energy, power and cycle life comparable to Li-ion technology.1

Among cathode candidates, layered oxides offer many advantages due to their simple structures, high capacities, and ease of synthesis. However, there are major challenges to overcome, such as: low operating voltage, long term stability of host structure, high polarisation and the stability of the sodium in the P2-phase.2 In general, ternary and quaternary transitional metal (TM­) systems offer the most advantages, due to the ability to tune the material with different TM at different percentages. SHARP Corp. have been developing a variety of layered oxides for sodium-ion battery applications. One of the most promising candidates to date is the quaternary TM system, NaNixSnyMnzTiyO2 giving an experimental capacity of 175 mAh/g and an average voltage of 3.2 V. However, the cycle stability of this material requires improvement. In order to understand this loss in capacity over cycle life, in-operando x-ray diffraction was carried out in coin cell configuration vs hard carbon, containing either one or two beryllium windows depending on the x-ray source used. Initially, this project looked at the material in-situusing low energy laboratory x-ray diffraction, but the energy of the x-ray source is not sufficient to identify the different phase transitions throughout sodiation/desodiation. By means of using a synchrotron x-ray source and following real-time electrochemical performance, this experiment has allowed the identification of key phase transitions throughout initial sodiation at a rate of C/20 then continued cycling at a rate of C/10. What is particularly interesting is the corresponding phase transition that occurs at high voltage, with a defined plateau from 3.9 to 4.3 V. The corresponding redox reaction is unstable thus small loses of capacity is observed through cycling. By identifying this phase, and understanding what the structural changes to the cathode material are, there is the possibility to tune this material and therefore stabilising this high voltage phase-transition.
Sion Power's Licerion®
High Energy Batteries
Authors: Mikhaylik Yuriy
Published: February 2020

Sion Power Corporation has created
Licerion®

, a comprehensive battery system that significantly enhances energy and cycle life of rechargeable batteries with metallic lithium anode. The core element of Sion Power’s
Licerion®
technology is a physically protected metallic lithium anode. Physical protection is based on ceramic-polymer composite membranes and is combined with specialized electrolyte systems providing chemical protection of exposed metallic lithium surface. This approach addresses safety and cycle life problems that have historically plagued lithium metal electrodes. Protected lithium anodes are currently combined with intercalated metal oxide cathodes typically used for Li-ion batteries (
Licerion®
- Ion) and with advanced sulfur cathodes (
Licerion®
- Sulfur). Sion Power Corporation in collaboration with BASF is working aggressively on realizing the impressive potential of the
Licerion®
technology targeting 500 Wh/kg, 1000 Wh/L and 1000 cycles. This presentation will discuss:

Failure mechanisms of rechargeable batteries with metallic lithium anode.

Current status of 350 - 400 Wh/kg Sion Power cells with metal oxide and sulfur cathodes and their high power and extreme low temperature variations.

Approaches pursued by Sion Power in collaboration with BASF towards next generation of
Licerion®
- Sulfur and
Licerion®
- Ion batteries targeting to meet and exceed requirements for EV application and for extended unmanned aerial vehicle (UAV) flights.
Facile Synthesis of Hollow Mesoporous NiCo2O4 Nanostructures and Their Structural Evolution By Synchrotron X-Ray Diffraction As a Negative Electrode in Lithium-Ion Batteries
Authors: Yoo Jaeseung , Venugopal Nulu , Son Suhan , Oh Woong , Lew Gil Hwan , Palanisamy Kowsalya , Kim Yunok , Yoon Won-Sub
Published: February 2020

Mesoporous hollow nanostructures have been attracting remarkable attention because of their high surface area, robust structure and are indispensably have a great scope for basic studies. On the other side, binary metal oxides are considered to be as promising anode materials for lithium ion batteries, especially, NiCo2O4 is of a great virtue to overcome the current existing hurdles with anode materials, such as reversible capacity, structural stability, and electronic conductivity. Also, the reduction of high-cost and toxic metal, Co content in the NiCo2O4 in comparison with pure Co3O4 makes it more significant for mainstream applications. Herein we report a facile chemical synthesis method followed by thermal annealing in the air to attain three-dimensional (3D) arrangement of mesoporous NiCo2O4 hollow nanoparticles that are randomly organized into bundles of superstructures. This method can produce highly reproducible structures with gram quantities. Brunauer−Emmett−Teller (BET), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal that the surface area of the synthesized materials is determined to be 134 m2 g-1(narrow pore size distribution of 3-4 nm) with a unique porous morphology including nanoparticles/ flakes of about 5 to 50 nm in size range appeared on the surface of each hollow particle exert significant influence on the electrochemical performance. It is evidently exhibited by NiCo2O4 hollow superstructures electrode that the increase in lithium storage capacity and excellent cycling stability (1335 mA h g−1 at a current density of 100 mA g−1 after 30 cycles). Further, we have investigated the structural evolution of this new morphological electrode material by ex-situ X-ray diffraction using synchrotron X-ray beam during first and second consequent cycles tested at low scan rate (100 mA g−1). Moreover, this synthesis strategy can be extended to the preparation of other metal oxides for energy storage devices and for many other related applications.