bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards Safer Sodium-Ion Batteries Via Ionic Liquids As Electrolyte Additives
Authors: Monti Damien , Ponrouch Alexandre , Johansson Patrik , Palacin M Rosa 
Published: February 2020

Our society is in urgent need of more efficient, affordable and environmentally friendly energy storage technologies. While lithium-ion batteries (LIB) is undeniably the main track of development and outstanding at present, complementary technologies are needed for managing applications such as renewable energy integration. One particularly appealing alternative is to explore the feasibility of a technology analogous to LIB – sodium ion batteries (SIB) – using the basic LIB know-how and with sodium being more abundant and less expensive.
As in any battery technology, the electrolyte choice is as important as that of the electrodes to ensure successful operation. Considering both safety and “environmental impact” ionic liquids (ILs) have emerged as an interesting option for LIB. ILs exhibit both non-volatility and non-flammability, but unfortunately their high viscosities and comparatively low conductivities are expected to considerably limit the rate performance. Mixed electrolytes, i.e. with ILs as additives to an organic electrolyte, are a compromise suggested to improve the safety – while still providing an appreciable conductivity. Here, the possibility of expanding this strategy also to the SIB technology has been explored.
We here present a systematic study of several electrolytes consisting of a sodium salt (NaTFSI) dissolved in mixtures of ILs and organic solvents, using electrochemical techniques (cyclic voltammetry, chronopotentiometry) coupled to various safety tests (e.g. self-extinguishing time (SET) and flash point (FP)). Imidazolium (BMImTFSI/EMImTFSI) and pyrrolidinium (PYR13TFSI) ILs were used as additives to optimized ethylene carbonate: propylene carbonate (EC:PC) electrolytes, while Hard Carbon (HC) and Na3V2(PO4)3 (NVP) were used as anode and cathode, respectively. Electrochemical tests were performed on half cells to evaluate the cycling abilities and the electrochemical stability of each electrolyte/electrode combination. HC tested with the BMImTFSI-EC:PC electrolytes exhibit specific capacities of ca 250 mAhg-1 and 140 mAhg-1 at C/5 and 1C rates with capacity retentions of 95% and 98%, respectively. For PYR13TFSI-EC:PC ~150 mAhg-1 at C/10 rate a Coulombic efficiency of ca 98% was achieved. The NVP electrode, exhibits capacities of ~80 mAhg-1 with the BMImTFSI-EC:PC electrolytes at C/10 rate, and of 80, 75 and 46 mAhg-1 at C/10, C/5 and C, respectively with the PYR13TFSI-EC:PC electrolyte. A successful full SIB cell was assembled based on the best choices of the above materials as a proof of concept. As a major argument for the use of ILs is an increased safety, it was encouraging that the safety tests, carried out in air for many different compositions, unambiguously proved the addition of ILs to decrease the SET, as well as the flame intensity, and simultaneously raise the FP.
Mediating Gel Formation from Structurally Controlled Poly(ionic liquids): Towards Ionic Gel Electrolytes for Energy Storage
Authors: Srour Hassan , Ratel Olivier , Leocmach Mathieu , Denis-Quanquin Sandrine , Appukuttan Vinukrishnan , Taberlet Nicolas , Majesté Jean-Charles , Carrot Christian , Manneville Sebastien , Andraud Chantal , Bucher Christophe , Monnereau Cyrille 
Published: February 2020

Most sustainable energy sources (solar, hydropowered, geopowered, windpowered) rely on the production of electrical energy. In the last decade, Lithium ion based batteries have emerged as interesting candidates as high-density energy storage devices, enabling the developments of electrical vehicles of constantly growing autonomies. The synthesis of polymer electrolytes and the study of their electrochemical properties is currently a very active topic. Poly(ionic liquids) (PILs), in particular, constitute an increasingly sought-after category of materials, as they are expected to replace flammable, leakage-prone organic solvent electrolytes in future energy storage devices.[1,2]

In this communication, we will present a novel synthetic methodology, which provides an easy access to a broad range of PILs from a common monomeric precursor (figure 1). Owing to this straightforward conceptual approach, it is possible to precisely control the structure of the polymeric materials. We will show how the introduction of an anionic functional group on the ATRP initiator is enough to mediate gel formation at low concentrations through electrostatic interactions (Figure 2).[3,4]
We will then demonstrate that the incorporation of different additives along the polymer backbone helps optimizing ionogel properties in different electrolytic solvents to form gel electrolyte. Finally, we will illustrate the potential of the resulting gels as quasi-solid materials for energy storage applications through the study of different parameters: its rheological behaviour, electrochemical stability, diffusion and ionic conductivity properties.
[1] Yoshizawa, M.; Ogihara, W.; Ohno, H. Polym.
Adv. Technol.
2002,
13, 589-594.
[2] Wang, P.; Zakeeruddin, S. M.; Moser, J. E.; Nazeeruddin, M. K.; Sekiguchi, T.; Gratzel, M. Nat Mater
2003,
2, 402-407.
[3] Appukuttan, V. K.; Dupont, A.; Denis-Quanquin, S.; Andraud, C.; Monnereau, C. Polym. Chem.
2012,
3, 2723-2726.
[4] Srour, H.; Ratel, O.; Leocmach, M.; Adams, E. A.; Denis-Quanquin, S.; Appukuttan, V.; Taberlet, N.; Manneville, S.; Majesté, J.-C.; Carrot, C.; Andraud, C.; Monnereau, C. Macromol.
Rapid Commun.
2014, DOI: 10.1002/marc.201400478.

Figure 1
X-Ray Micro-Tomography As a Diagnostic Tool for the Electrode Degradation in Vanadium Redox Flow Batteries
Authors: Trogadas Panagiotis , Taiwo Oluwadamilola O , Tjaden Bernhard , Neville Tobias P , Yun Sukhwan , Parrondo Javier , Ramani Vijay K , Coppens Marc Olivier , Brett Dan J. , Shearing Paul R. 
Published: February 2020

The vanadium redox flow battery (VRFB) is an electrochemical device suitable for large-scale energy storage due to its fast response time, long cycle life, and high energy efficiency1. In VRFBs, the electrodes provide the sites to facilitate the redox reactions between V3+ / V2+ and V4+ / V5+ ions2.
Graphite felt is the most common electrode material employed in VRFBs due to its low cost, high stability and conductivity, and reasonable surface area3. Micro-tomograms of fresh graphite felt have already been obtained and used to extract detailed structural characteristics of electrodes4. Based on the acquired structural information, 3D pore scale models have been built to investigate the effect of electrolyte flow rate, vanadium ion concentration and electrode morphology on VRFB performance.
However, even though this model-based design approach has helped optimize the fresh felt material, pore scale models for VRFBs would be much more accurate and realistic if the structural information of used (voltage-cycled) felts were incorporated in the model to capture the changes in felt structure and properties during operation.
Using a combination of micro-tomography (CT) measurements of voltage-cycled graphite felts (over ca. 30 charge / discharge cycles), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) measurements of the same felt electrode, the first description of micro-structural evolution processes occurring in VRFB felts during operation is provided.
Reconstructed 3D images of the VRFB electrodes reveal fiber agglomeration and carbon electrochemical oxidation during continuous battery operation (Fig. 1a and b). Key geometric characteristics of the graphite felt samples are extracted from these 3D images allowing the calculation of porosity, tortuosity and volume specific surface area for each sample. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) measurements have been also employed in order to verify the significant structural changes on voltage-cycled graphite felts observed by micro-CT.

References

1. A. Weber et al., J. Appl. Electrochem., 41, 1137 (2011).
2. A. Parasuraman et al., Electrochim. Acta, 101, 27 (2013).
3. B. Li et al., Nano Letters, 13, 1330 (2013).
4. G. Qiu et al., Electrochim. Acta, 64, 46 (2012).
Figure 1. 3D reconstructed image of the fresh (A) and voltage-cycled (B) graphite felt electrode respectively.

Figure 1
High Rate Capacity through Redox Electrolytes Confined in Macroporous Electrodes
Authors: Narayanan Rajaram , Bandaru Prabhakar R 
Published: February 2020

The capacitive characteristics of a model macroporous electrode, comprised of vertically aligned carbon nanotubes, with a relatively large volume /unit mass (of∼40 cm3/g) are discussed. The faradaic characteristics of the capacity were evidenced through a voltage plateau in the galvanostatic discharge experiments. It is shown that the conﬁnement of electrolyte within the spacing between the nanostructures with respect to an appropriate choice of the voltage scan rate yields a regime where both high capacity and rate capability may be realized. Additionally, the absence of diffusional processes allows for large capacitance retention even at discharge current densities of the order of 200 mA/cm2. For 1M K3Fe(CN)6, the maximum observed capacity was found to be ∼26 mAh/cm3 (normalized to the pore volume) or 0.28 mAh/cm2 (normalized to the projected area of the electrode) and it was noted that the capacity could be cycled at very high rates for 5000 cycles.1

References:
1. R. Narayanan and P. R. Bandaru, J. Electrochem. Soc., 162, A86–A91 (2015)

Figure 1
A Disruptive Concept for a Whole Family of New Battery Systems
Authors: Roumi Farshid , Cid Clement , Roumi Jamshid , Hoffmann Michael R 
Published: February 2020

We propose a radically new approach to the architectural design of batteries. The invention is a new geometry that replaces conventional cell and module designs and significantly reduces the weight, volume and cost of non-active materials, while increasing the thermal performance. The new battery relies on an innovative architecture called an S-cell. The proposed cell geometry may increase the energy per cost or weight by a factor of 2, by significanlty reducing the manufacturing cost and by enabling high capacity electrode materials.
Can Radiolysis Help Understanding the Decomposition Products of the Electrolytes Used in Lithium-Ion Batteries?
Authors: Ortiz Daniel , Maître Philippe , Mostafavi Mehran , Le Caër Sophie 
Published: February 2020

Lithium-ion batteries appear to be one of the most important advances in energy storage. Unfortunately, their performance declines gradually with their use and/or time. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role and radiolysis is an interesting approach in order to simulate the ageing phenomena.
One of the aims of our group is then to investigate the effect of ionizing radiation on the different solvents containing or not lithium salts used in batteries. We generate, thus, the decomposition products that are actually comparable to those formed by electrolysis. Moreover, the use of the “radiolysis approach” entails particularly two important benefits: the time needed to degrade the solvent is much shorter than in classical charge/discharge cycles and it offers the possibility to explore different time scales processes (from picoseconds to days).
Our work was first focused on linear alkyl carbonates diethyl and dimethyl carbonate (DEC and DMC) with/without LiPF6. At short-time scale, picosecond pulse radiolysis has been used in order to explore the primary radiation effects. These experiments reveal, for instance, an unambiguous reaction between the electron and the PF6
- anion.
Then, the long-time decomposition products were analyzed both in the gas and liquid phase. To this end, a wide variety of analytical techniques has been used. Gas phase has been analyzed and quantified using Gas Chromatography-Electron Impact-Mass spectrometry (GC-EI-MS) whereas a combination of Electrospray-High Resolution Mass Spectrometry (ESI-HRMS) with both Ion Mobility Spectroscopy (IMS) and Infrared Multi-Photon Dissociation (IRMPD) spectroscopy has been used to characterize the decomposition products in the liquid phase.
In conclusion, we show that the “radiolysis approach” used herein can provide an unprecedented, quantitative and fast overview of the electrolyte decomposition phenomenon.
Optimization of MnO2 Cathodes for Aqueous Battery Applications
Authors: Hertzberg Benjamin Joseph , Phadke Satyajit , Davies Greg , Chamoun Mylad , Hsieh Andrew , Rus Eric D. , Moon Geon Dae , Erdonmez Can K. , Meng Shirley , Steingart Daniel A 
Published: February 2020

Grid-level energy storage demands a low-cost, safe, long cycle life battery chemistry. The Zn-MnO2 alkaline battery chemistry hits the first two targets. This type of battery has high energy density (comparable to that of a Li-ion battery) and low cost per kilowatt-hour. However, their rechargeability is limited by phase transformations which occur in the MnO2 cathode during discharge of close to one electron, which transforms it into an spinel phase, generally considered to be electrochemically inert. As a result, depth of discharge is limited to no more than 70% of the 1e- capacity of MnO2 at best, and in a large format cell typically no more than 0.5 e-.
We have extensively studied the MnO2 alkaline system and have developed a variety of techniques to extend this depth of discharge window, improving the capacity and cyclability of the cell dramatically. We have also developed novel nanostructured forms of MnO2 for use as a cathode material in this system. Using these techniques, we have achieved capacities of over 350 mAh/g (1.2 e-) for more than 150 cycles. In this presentation, we will discuss the various failure modes of the MnO2 alkaline system, and the techniques our group has developed to overcome them. We will describe the crystal structure and electrochemical performance of the nanomaterials we have synthesized, as well as the structural changes occurring during their use as an electrode material as characterized via synchrotron radiation and other techniques.
With further development, this material, combined with either a zinc anode or an earth abundant, insoluble anode such as Fe or Cd, may allow for over 1000 cycles at a cost of less that $100/kWhr for a packed out cell. Figure: a) MnO2 electrode before cycling; b) MnO2 electrode after 1st-electron discharge; c) MnO2 electrode after full discharge; d) MnO2 electrode after full recharge; e) MnO2 electrode after 3 cycles (discharged state); f) MnO2 electrode after 15 cycles (discharged state)

Figure 1
Investigation of Electroplating Trivalent Cr-C on Copper Alloy As Bipolar Plates with Different Current Density in Pemfcs
Authors: Wang H.C. , Hou K.H. , Lu C.E. , Ger M.D. 
Published: February 2020

In this study, the trivalent Cr-C coating was electroplated on copper alloy as bipolar plates because of their excellent electric conductivity and corrosion resistance. The SEM images showed that the thickness of the coating was about 2 to 13 μm and increased with raised coating current density. The surface morphology at 10 A/dm2 is more smooth, no cracks and has high carbon content (46.65 at％). Moreover, the polarization curve with different coating current density (10, 30, 50 A/dm2) represented the coating prepared at 10 A/dm2 and 10 minutes possessing the lowest corrosion current density (Icorr=1.9 x 10-
7 A/cm2). At contact resistance measurement, we got value (3.2 mΩcm2) at 10 A/dm2 which less than the standard of DOE (20 mΩcm2). The results of single cell test showed better performance (about 338.0 mW/cm2) at 10 A/dm2.

Figure 1
Research on Unitized Regenerative Fuel Cell Stack with Producing High Pressure H2 and O2 in WE Mode
Authors: Zhang Xinrong 
Published: February 2020

A unitized regenerative fuel cell (URFC) is an electrochemical energy storage device that combines a fuel cell and a water electrolyzer in a single system. The URFC is an excellent clean, quite energy source and are promising energy storage systems for uninterrupted power supplies, solar powered aircraft, and satellites. In the paper, the high pressure unitized regenerative fuel cell was developed and validated with a capacity of producing hydrogen and oxygen at a pressure of up to 5MPa in the water electrolysis mode.
The bifunctional performance of URFC stack in the hydrogen and oxygen fuel cell (FC) and water electrolysis (WE) modes and the generated gases pressure influence on URFC stack were investigated. The main electrochemical element is bifunctional membrane electrode assembly (MEA) with an active area of 200cm2 which consists of polymer electrolyte membrane from Dupont and the electrode layer on both sides of the membrane by catalyst coated on membrane technique (CCM). Oxygen electrode layer was prepared by Pt/IrO2mixing catalysts. Hydrogen electrode layer was prepared by 40%Pt/C (J.M.). The diffusion layer of MEA was the porous sintered metal foil with corrosion resistance.
Primary test results illustrated that high pressure URFC stack exhibited the promising bifunctional performance. The static seal level of URFC stack was up to 10MPa and the dynamic gas pressure reached 5MPa in the water electrolysis mode. Figure1 showed that the stack output electric power was greater than 1.2kW at a current density of 1000mA/cm2in the fuel cell mode.
Figure 2 showed that the generated gases pressure had few influence on the performance of the stack in the water electrolysis mode under working conditions. The single cell voltage was 5~12mV higher at the generated gases pressure of up to 5MPa when the current density was less than 700mA/cm2. However the single cell voltage was 5~10mV lower at the generated gases pressure of up to 5MPa when the current density greater than 700mA/cm2. The stack showed good pressure adaptability. The round-trip energy conversion efficiency of high pressure URFC stack was greater than 45% at the current density of 500mA/cm2.
In addition, the cycling test of the stack during URFC operation was performed in both fuel cell and water electrolysis modes. The results indicated that high pressure URFC stack had the promising cycling stability. Further research and validation are still underway.

Figure 1
Improvement of Cycle Life of Lithium Air Batteries Using Ag and Mg Alloyed Li Anode
Authors: Algül Hasan , Tokur Mahmud , Uysal Mehmet , Cetinkaya Tugrul , Alp Ahmet , Akbulut Hatem 
Published: February 2020

Lithium-air batteries have attracted great interest due to great theoretical specific energy of Li-air excluding oxygen is 11.5 kWhkg−1, the value of which is comparable with that of gasoline/air device. This high energy density battery has the potential to be the power source for the advanced electric vehicles. However, there are a lot of challenges, one of which is low cycleability of lithium-air batteries because of formation dendrites on lithium anode and most significantly very high corrosion of lithium metal when room temperature ionic liquids (RTILs) are used. In this study, it was aimed to increase corrosion resistance therefore, cycleability of anode materials in Li-air battery cells by using mechanical alloying with silver and magnesium powders.
The effect of the silver and magnesium on the electrochemical behavior of lithium anode for lithium-air batteries were investigated. Fine granules of Li metal and silver or magnesium were used as starting materials. At the first step the production of the Li-Ag and Li-Mg alloys was optimized in the mechanical alloying process. Subsequently, Li-Ag or Li-Mg powder alloys were synthesized as anode materials. The high energy ball milling was performed under argon atmosphere at room temperature. The alloys produced by mechanical alloying were cold pressed to produce dense lithium alloys. The physical characterization of the produced anodes was evaluated by X-ray diffraction (XRD) and scanning electron microscopy(SEM). Electrochemical analysis of the lithium and lithium alloys were carried out using a Swagelok-type cell with 1 M LiPF6 in TEGDME as electrolyte and GDL (gas diffusion layer) as cathode and prepared Li-Ag and Li-Mg powders as working anode. The electrochemical impedance spectroscopy (EIS) measurement of the lithium and alloys have been conducted to investigate the difference in the resistance of the cell before and after electrochemical cyclic test.
Improvement of Charge Transfer Resistitance of Cathode in Ni-MH Batteries Using Ni/Al-LDH Prepared By Liquid Phase Deposition Method
Authors: Mizuhata Minoru , Takigawa Masashi , Maki Hideshi 
Published: February 2020

Much attention has been paid to the layered double hydroxides containing transition-metal elements for various electrochemical devices. Nickel-aluminum layered double hydroxide (Ni-Al LDH) is the promising materials for the positive electrode of Ni-MH battery because of its good electrochemical properties and high stability in strong alkaline keeping the structure of α-Ni(OH)2. Furthermore, α-Ni(OH)2 have higher capacity than β-Ni(OH)2 which is commonly used for the electrode materials of Ni-MH battery, but less stability in strong alkaline. Generally, electrode is prepared by painting colloidal active materials, however, the internal resistance in the electrode is high. Improvement of the adhesion between current collector and active materials contribute to reduce the internal resistance, especially charge transfer resistance (R
ct) of an electrode reaction. Previously, we reported the precipitation of Ni-Al LDH with high crystallinity and high purity by the liquid phase deposition (LPD) method. The LPD method is the syntheses method of metal oxides and hydroxides using the hydrolysis reaction of metal fluorine complexes. The merits of LPD method are easy operation and following capability for substrate surface shape. In this study, the Ni-Al LDHs were directly prepared on the surface of Ni foam as a current collector of Ni-MH battery, and investigated the reduction effect of the R
ct. From the cross-sectional SEM images of the sample, dense Ni-Al LDH was deposited on the Ni foam surface, and the thickness was up to 950 nm. The resistance of charge transfer, R
ct was measured by an ac impedance spectroscopy at 0.5 V vs Hg/HgO. The apparent activation energy of chage transfer is calculated from Arrhenius plots of the temperature dependence of R
ct values. The composition of LDH was determinded by ICP-AES spectroscopy for Ni and Al, and neutralization titration for OH, as Ni0.95Al0.05(OH)2·A
0.05 ,where A is exchangable anionic species. Deposition of Ni-Al LDH on the surface of Ni foam directly reduced the R
ct because of the improving the adhesion between current collectors and active materials as shown in Figure 1. In this case of using the sample where the Ni/Al LDH layer is deposited, the value of R
ct decreased with the thickness of LDH layer on the Ni metal form from ca. 0.8 to 0.2 Ω cm-2, where those values for the sample using LDH power increase over 0.8 Ω cm-2. Furthermore, the activation energy for the electrode reaction decreased from 22.3 to 17.9 kJ mol-1 . It is suggested that the ionic transport becomes easily in the LDH layer and are coupled electronic conduction from Ni form using deposited Ni/Al LDH on Ni form. This Ni-Al LDH/ Ni foam composite will be able to provide a secondary battery electrode having high charge transfer efficiency.

Figure 1