bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Novel High Energy Density Sodium Layered Oxide Cathode Materials
Authors: Gruar Robert , Adamson Paul , Smith Katherine , Treacher Joshua , Ledwoch Daniela , Kendrick Emma 
Published: February 2020

The large-scale utilisation of renewable energy technologies depends on solving the intermittency of energy production with large scale energy-storage solutions. The Lithium-ion battery has been widely considered as the technology of choice to meet the future energy challenge. However, increasing demand for Li based energy storage technologies is likely to tax current Li production. There is growing research and commercial interest in other metal ion battery technologies that could be developed to meet the needs of large scale energy storage applications. As such, the room temperature Na-ion secondary battery has been the subject of increasing research and development due to its feasibility to compete with the already well-established Li-ion secondary battery.1 Although, there are many technical barriers to overcome before Na-ion technology becomes competitive with current metal ion batteries. However, recent research into Na-ion systems has shown that some of the known Na-ion battery materials have advantages over the current Li-ion counterparts.2

In this publication, we present detailed characterisation of novel sodium ion cathode materials based on a layered oxide framework as strong candidates for Na-ion battery cathode materials. We will present a review of layered oxides (Na Nix TMyO2, TM = Ti, V, Cr, Mn, Fe, Co, Ni, and a mixture of 2 or 3 elements). Single TM layered oxide systems are well characterised not only for their electrochemical performance but also for their structural transitions during electrochemical cycling.1 Binary TM systems are often favoured as modifications through doping seem to address issues of low reversible capacity, capacity retention, operating voltage, and structural stability when compared to the single TM analogues.2 As a consequence, some materials already have reached a specific energy density of 578 mW h g−1 comparable to that of LiFePO4.3 Furthermore, some binary and ternary TM systems have shown exceptional stability and rate capability.4

Herein, we present development work of Na Nix Mny TM1TM2 O2 quaternary and higher substituted sodium layered oxides.5 We demonstrate that further substitution within the layered oxide structure is beneficial to improving reversible capacity, capacity retention and operating voltage of these materials. These higher order substitutions leading to materials which show comparable electrochemical properties to simple Li ion technologies. We have begun development of Full cell technology based on some of the best performing layered oxides.

N. Yabuuchi, et al. Chem. Rev., 2014, 114 (23), pp 11636–11682

L. Yuechuan, et al. Chem. Mater. 2014, 26, 5288−5296

X. Li et al. Electrochemistry Communications 49 (2014) 51–54

H. Yoshida, N. Yabuuchi and S. Komaba Electrochem. Commun., 34 (2013), pp. 60–6

J. Barker, et al. Doped Nickelate Compounds WO 2014/009710A1
Evidence for a Mixed-Phase Discharge Product and Superoxide-Mediated Discharge Pathway in a Mg/O2 Battery
Authors: Vardar Gulin , Sleightholme Alice , Siegel Donald J , Monroe Charles W 
Published: February 2020

Metal/O2 batteries have the potential to achieve extremely high energy densities, and metal/O2 batteries based on magnesium are predicted to have one of the highest.1 Shiga et al. have demonstrated rechargeable, non-aqueous Mg/O2 cells that operate above room temperature.2
,
3 The need for elevated temperatures can be negated by using a Mg2+ electrolyte that can deposit and dissolve Mg at room temperature. We have produced Mg/O2 test cells using a modified-Grignard-reagent electrolyte, which has oxidative stability higher than 4V vs. Mg/Mg2+ and is viable at room temperature.4

We will discuss our progress in exploring discharge and recharge characteristics of non-aqueous Mg/O2 cells. Although Mg/O2 batteries have been demostrated using non-aqueous electrolytes in the past, the nature of the discharge product is not well understood. Figure 1 shows the discharge product on a porous-carbon positive electrode after first discharge. We have elucidated the Mg/O2 discharge-product composition using several characterization techniques, including scanning electron microscopy, energy dispersive spectroscopy, Auger electron spectroscopy, X-ray diffraction and Raman spectroscopy. The discharge product predominantly comprises MgO. In addition to MgO, there is evidence of a substantial minority of MgO2, as well as trace Cl. The energy efficiency for the first cycle is 42%, lower than other metal/O2 chemistries,5
,
6 but comparable to prior elevated-temperature Mg/O2 cells.2

The open-circuit potential (OCP) prior to first discharge of the non-aqueous Mg/O2 cell is 2.0V, which is lower than would be expected for the direct electrochemical formation of MgO or MgO2 (2.95V and 2.91V vs. Mg/Mg2+, respectively). This observation is consistent with discharge-product formation via a superoxide-ion intermediate, which forms from molecular O2 at 2.03 V vs. Mg/Mg2+. Superoxide then drives an O2-releasing precipitation of MgO2, which subsequently disproportionates to O2 and MgO – chemical reactions that do not affect the cell voltage, and rationalize the observed discharge-product composition.
(1) Zu, C.-X.; Li, H. Energy Environ. Sci.
2011, 4, 2614.
(2) Shiga, T.; Hase, Y.; Kato, Y.; Inoue, M.; Takechi, K. Chem. Commun. (Camb)
2013, 49, 9152.
(3) Shiga, T.; Hase, Y.; Yagi, Y.; Takahashi, N.; Takechi, K. J. Phys. Chem. Lett.
2014, 5, 1648.
(4) Nelson, E. G.; Brody, S. I.; Kampf, J. F.; Bartlett, B. M. J. Mater. Chem. A
2014.
(5) Hartmann, P.; Bender, C. L.; Vračar, M.; Dürr, A. K.; Garsuch, A.; Janek, J.; Adelhelm, P. Nat. Mater.
2013, 12, 228.
(6) Ren, X.; Wu, Y. J. Am. Chem. Soc.
2013, 135, 2923.

Figure 1
Interface Study of All-Solid-State Lithium Batteries with Garnet-like Structure Llzo Electrolyte
Authors: Lee Jae Myung , Lee In Sung , Nam Sang Cheol , Kim Do Hyeong 
Published: February 2020

All-Solid-State Lithium battery, which is consist of solid electrolyte, is expected the most promising candidate for next generation energy storage devices for its high safety, high energy density and long cycle life 1-3]. Because all these advantages were attributed to the electrolyte materials, most of the studies are focused on the electrolyte materials themselves.
Among many other lithium ionic conductors, the Garnet-like structure LLZO (Li7La3Zr2O12) is the most promising candidate for its high ionic conductivity (~0.1mS/cm), non-reactivity with air, and high chemical stability both with lithium metal and oxide cathode materials. There are many reports about modification of LLZO with doping elements and structural changes of LLZO, however, there are less reports of manufacturing process of All-Solid-State lithium batteries with LLZO or interfacial properties between cathode and electrolyte.
In this study All-solid-state lithium batteries with two different types of LLZO electrolyte/cathode composite electrodes were manufactured. The first type was based on sputtering process and the second one was based on co-firing process. (1) type 1 : Electrolyte green sheets were casted by dry casting, then they were sintered in oxygen environment. Each electrode was polished by sand papers to get a flat surface, and it was installed in vacuum chamber for sputtering of LiCoO2 layer. The thickness of sputtered LiCoO2 cathode film was 1um. (2) type 2: the cathode and electrolyte composite green sheets were casted by dry casting method. Those composite green sheets were sintered simultaneously (co-firing) in oxygen environment. The Lithium metal anode layer was prepared on the surfaces of the electrolyte sides in those composite electrodes by thermal deposition method and a gold film was deposited by sputtering process on the surfaces of the cathode for current collection. The Electrochemical properties of composite electrodes were evaluated by charge-discharge cycle test and electrochemical impedance analysis method. The interfaces in composite electrodes between cathode and electrolyte were investigated by spectroscopic methods.
Referecnes
[1] Ramaswamy Murugan,et al. Angew. Chem. Int. Ed. 2007, 46, 7778 –7781.
[2] Ezhiyl Rangasamy, et al. Solid State Ionics 206 (2012) 28–32.
[3] Kai Chen, et al. Electrochimica Acta 80 (2012) 133– 139.
Modeling Electrochemical Reactions - Methods, Phenomena and Problems from Metals to Oxides to Organics
Authors: Auer Alexander A 
Published: February 2020

Catalytic reactions involing oxygen are omnipresent in modern science. May it be in cellular respiration, in corrosion processes
or in energy conversion and storage, the reduction and evolution of this species plays a central role. In Biology, for example
iron or manganese containing enzymes efficiently cleave of form the oxygen-oxygen bond. In fuel cells, platinum aids in converting
the energy stored in hydrogen and oxygen. In electrolyzers, iridium oxide might be the catalyst of choice for oxygen evolution.
If one now considers approaches for the simulation of the electronic structure of systems like metals, oxides and enzymes, one
finds that very different approaches are applied, even different communities and schools exist - Terms like solid state physics, semiconductor
physics, quantum chemistry or bioinorganic chemistry come to mind. Is this merely a reflection of the historical process in which these
disciplines evolved, or is there an expalanation why catalytic reactions on metals are treated with a very different toolbox from the methods common
in biocatalysis ?
Im my presentation I will give an overview of the phenomena in oxygen reduction and evolution and discuss differences and similarities
of electrocatalytic reactions for metals, metal oxides and molecules. A central scheme will be the electronic structure focusing on the
availability to supply charge and spin to the active site of a catalyst. This includes discussing the question when the energies of intermediates
are sufficient to understand a catalytic reaction or if transition states need to be included. Is it sufficient to have an estimate for the density of states
in order to understand heterogenous reactions or are more details required to identify the major influences for catalysis ?
This overview, which is meant to inspire different fields to join their effords,
will be illustrated by examples from my own work on platinum nanoparticles and extended carbon structures,
by examples from our department on biocatalysis as well as examples from the literature.
Finite Thickness Effects on Nafion Properties in the PEMFC Catalyst Layer, Probed By in Situ Neutron Reflectometry
Authors: DeCaluwe Steven C , Dura Joseph A. 
Published: February 2020

A major technical challenge impeding the optimization of polymer electrolyte membrane fuel cells (PEMFCs) is a lack of understanding regarding Nafion properties inside the fuel cell catalyst layer (CL). Inside the CL, thin Nafion layers (typically on the order of 2 – 80 nm thick) cover solid electrode particles and agglomerates. In this thickness range, dimensional confinement and interfacial effects at solid, liquid, and vapor phases alter the properties of the films. While recent studies have explored water content and transport properties in this thickness range to demonstrate reduced water mobility for films below roughly 60 nm in thickness, the effects of thickness and substrate variation on water uptake and Nafion structure in this range are still debated. Thus far, an unambiguous documentation of Nafion composition and structure for thicknesses typical of the PEMFC CL has not been presented. We present here the use of neutron reflectivity (NR) as an in situ probe of structure and composition for Nafion films with thicknesses of 5 – 200 nm. NR measurements provide simultaneous thickness and composition information for thin-films under controlled conditions, via an SLD depth profile with sub-Ångström resolution for structural elements thicker than roughly 1.5 nm. Neutrons transmit easily through sample chamber walls and have an inherent sensitivity to hydrogen isotopes, with a large SLD variation between H and D isotopes, making NR ideal for in situ measurements of thin-film Nafion hydration.
Through the application of multiple NR measurements, elemental conservation, and Bayesian analysis, results presented will document varying water sorption and interfacial structures in thin-film Nafion for varying thickness, substrates, and humidity levels. Results provide an unambiguous confirmation of the reduced water sorption with reducing thickness below 60 nm, a detailed analysis of the sheet-like lamellar phase segregation on SiO2 substrates, as well as an illustration of how substrate modification can affect Nafion properties. Figure 1 shows the variation in water sorption with varying film thickness. As previously observed, for layers that approximate the phase-segregation of bulk Nafion films (“bulk-like”) water uptake decreases steadily for film thicknesses below 60 nm. However, within multi-lamellar polymer structures found at hydrophillic substrate interfaces, the water content reaches a minimum for films roughly 20 nm thick, and increases for films thinner than 15 nm. Furthermore, the average water content within the multi-lamellar structures is slightly higher than in the bulk-like outer layers. Simple numerical simulation results will be presented to discuss the implications of Nafion structural and composition variations in the CL for PEMFC performance.

Figure 1
PEM Fuel Cell Electrodes Prepared By Photocatalytically Deposited Pt on TiO2 and Successive Electrospinning
Authors: Narayan Manoj Krishna Kayarkatte , Delikaya Öznur , Roth Christina 
Published: February 2020

For successful commercialization of low temperature proton exchange membrane (PEM) fuel cells, the system should have a long life and a high performance. Further, to make them cost effective a decrease in Pt loading is also deemed necessary.
Pt supported on titania nanoparticles have shown to possess high stability. Unlike standard carbon, TiO2 itself doesn’t corrode in fuel cell operation conditions. Also, TiO2 is shown to form stronger bond with Pt owing to ‘strong metal support interaction’ (SMSI) [1], increasing the stability of the system itself. Due to the oxygen spillover effect, titania also acts as a co-catalyst, enhancing the oxygen reduction reaction [2]. Here, Pt/TiO2 is prepared by reducing a Pt precursor photocatalytically under UV illumination and directly on the support [3].
Recently in another development, electrospinning was found as an efficient way to prepare porous electrodes with very low Pt loading [4]. Electrospinning facilitates the preparation of a variety of fiber networks and architectures thus enabling to achieve porous structures which are required to enhance the sluggish oxygen reduction reaction and decrease the platinum loading in a PEM fuel cell. The versatility of electrospun materials not only depends on the precursor, but also on modifying the solution and process parameters, giving a considerable control over the morphology.
In this work, these two things are integrated together. First Nafion containing a small amount of PAA is mixed to form the electrospinning solutions with addition of Pt precursor along with titania in different amounts to obtain various loadings. In the presence of a strong source of UV light the Pt precursor is reduced to Pt and deposits itself on the TiO2. Fig. 1 shows the scanning electron micrograph of the 20 wt.% Pt/TiO2 catalyst held on a fibrous PAA/Nafion structure. The catalyst layer is prepared by electrospinning directly onto the GDL. The obtained catalyst layer is hot pressed on Nafion membrane to fabricate membrane electrode assembly, which will be later studied for H2/O2 fuel cell system.
References:
[1] Tauster SJ. Acc Chem Res., 20,389–94 (1987).
[2] Diebold U. Surf Sci Rep., 48,53–229 (2003).
[3] Ma J, Habrioux A, Alonso-Vante N. J Solid State Electrochem., 17,1913–21(2013).
[4] Cavaliere S, Subianto S, Savych I, Jones DJ, Rozière J. Energy Environ Sci., 4,4761(2011).
Fig. 1 Scanning electron micrograph of electrospun PAA/Nafion fibers containing 20 wt.% Pt/TiO2

Figure 1
Characterization of Carbon Fiber Electrode for Vanadium-Based Redox Flow Batteries
Authors: Narita Ayumi , Kaneko Yuji , Sato Yukari , Negishi Akira , Nozaki Ken , Kato Tohru 
Published: February 2020

Electrochemical properties of vanadium-based redox flow batteries (RFB) depend on many factors, such as redox chemical species, electromotive force, concentration of active materials, viscosity of electrolyte solution, electrode materials, electrode characteristics, and so on. One of the most important factors that regulate the RFB performance is the properties of electrodes.
In the case of actual vanadium-based RFB, carbon felt/fiber electrodes were used. Electrochemical performance of such carbon felt/fiber electrodes was treated in average. To evaluate RFB properties quantitatively, we adopted carbon single fiber electrode.
Carbon single fiber electrodes were prepared from carbon electrodes for vanadium RFB to examine the relationship between the carbon electrode and battery performance. Carbon single fiber electrodes were evaluated electrochemically. Statistical analysis was applied for about 10 carbon single fiber electrodes. Electrochemical responses of carbon fiber electrodes were compared with the previous results [1].
References:
[1] H. Kaneko, K. Nozaki, Y. Wada, T. Aoki, A. Negishi, and M. Kamimoto, Electrochim. Acta, 36, 1191 (1991).
Experimental Investigation of the Influence of Pressure on the Performance of Polymer Electrolyte Water Electrolysis Cells
Authors: Suermann Michel , Schmidt Thomas J. , Büchi Felix N 
Published: February 2020

Fluctuating electric energy production from renewable sources is increasing. While this is desired from an environmental point of view because production does not match consumption, storage is required to avoid curtailment [1]. Dynamically operable polymer electrolyte water electrolysis (PEEC) may be used to convert excess electric energy from fluctuating sources into chemical energy, i.e. hydrogen and oxygen [2]. For storage, transportation or methanation of hydrogen and optionally oxygen, pressure levels up to 300 bar, for mobility up to 800 bar are needed.
Conventional, mechanical compression of hydrogen to the above mentioned pressure levels is inefficient, noisy and many compression stages are required which cause high investment costs and intensive maintenance. In contrast, electrochemical compression in high pressure (HP) PEEC promises to be more efficient, silent and low maintenance. On the one hand theoretically higher pressure leads to higher thermodynamic voltages, while on the other hand it may decreases the transport losses due to smaller gaseous bubbles, especially at high current densities [3].
Experimental results of HP-PEEC up to several hundred bar are discussed, investigating the influence of HP on transport losses at high current densities. The evolution of the different overvoltages (kinetic, ohmic, mass transport), determined using high frequency resistance measurements and tafel extrapolation, is discussed as a function of gas pressure. In detail the influence of different porous titanium sinter current collector media on mass transport losses is discussed as function of temperature, pressure and current density. It is shown that there seems to be an optimum average pore diameter at about 10 µm (Fig. 1).
Literature:
[1] C. J. Barnhart, et al., Energy Environ. Sci., 6 2804-2810 (2013).
[2] F. Barbir, Solar Energy, 78(5) 661-669 (2005).
[3] S. A. Grigoriev, et al., International Journal of Hydrogen Energy, 34(14) 5986-5991 (2009)

Figure 1
Recent Advancements in Redox-Flow Cells and Promising Opportunities
Authors: Perry Mike L. 
Published: February 2020

Redox-Flow Cells (RFCs) possesses several key advantages that make this technology potentially well suited for large scale energy-storage applications. This is especially true of applications that require high energy-to-power requirements (i.e., multiple-hour discharge times at rated power), since the energy capacity can be increased by simply adding reactant solution without necessarily requiring (or negatively impacting) the power-delivery components. Despite this inherent scaling-factor advantage relative to conventional battery systems, the initial capital cost of flow batteries has been the major barrier to commercialization of RFC-based products. Capital-cost targets for grid-scale energy storage are challenging; battery systems for major grid-scale applications must cost less ($/kWh) than those currently used for most portable or transportation applications. One attractive path to cost reduction is the development of RFCs with substantially higher power densities than conventional cells. United Technologies Research Center (UTRC) has recently developed and demonstrated high performance RFCs in stacks operating in complete Prototype RFB Systems. A summary of these results has been presented previously. Therefore, a major focus of this talk will be on new materials and concepts that can potentially enable additional RFC cost reductions. This includes both advanced cell materials (e.g., electrodes, separators/membranes, bipolar plates), as well as advanced reactant solutions. Key system-performance indices provide the basis for the formulation of key property requirements for these proposed advancements. A brief review of the state-of-the-art of each these major materials will be included, as well as some proposed advanced technologies. The major goal of this presentation is to help researchers focus on potential opportunities that have the greatest likelihood of yielding substantial improvements RFC technology that can have significant commercial impact.

Acknowledgements

The author would like to thank his multiple colleagues at UTRC who have been an essential part of UTRC’s advanced flow-battery team.
Building a Better Redox Flow Battery - Innovative Diagnostics to Visualise Reactant Transport
Authors: Rubio-Garcia Javier , Kucernak Anthony R. J. 
Published: February 2020

While the optimization of PEMFCs and RFBs require addressing multiple issues, both systems share an operation mechanism based on pumping a fluid (a gas or a liquid) containing chemically reactive species across the face of an electrode. As a consequence of this characteristic, a significant source of inefficiency is linked to mass transport limitations including high pressure drop or inhomogeneous reactant flow distribution across the electrode. Previously, strategies including infrared mapping, (1) magnetic resonance imaging (2) or neutron radiography (3) were employed in an attempt to investigate fluid transport phenomena (predominantly for fuel cells). However, although those studies rendered valuable results, the measuring procedures can be considered as expensive and require delicate equipment.
In this contribution, a simple and low cost methodology to study the mass transport processes in RFBs is presented. This approach relies on the instantaneous electrochemiluminescence of Luminol. By simply recording the emitted light with a low cost camera,(4) concentration profiles at the surface of the electrode were obtained presenting high temporal and spatial resolutions. In addition, modifications on the electrolyte formulation and flow rate permitted identifying turbulent flow areas located at the turn of the flow field as well as leading to the design of improved components.

References:

(1) Wang et al., Journal of Power Sources, 157, 181–187 (2006).
(2) Tsushima et al., Magnetic Resonance Imaging, 23, 255-258 (2005).
(3) Trabold et al., International Journal of Heat and Mass Transfer, 49, 4712–4720 (2006).
(4) Lopes et al., Journal of Power Sources, 274, 382–392 (2015).