bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Pulse-Reverse Nb Electropolishing with H2so­­
4 for Srf Cavities
Authors: Tian Hui , Reece Chalies E , Meyerson Melissa , McCord Cynthia
Published: February 2020

The performance of superconducting radiofrequency (SRF) cavities is greatly affected by the topography of the interior surface, so it is imperative that the surface be clean metal as smooth as possible. Currently, the 1:10 volume ratio HF (49%) and H2SO4 (96%) electrolyte was widely used for high field SRF cavity production, the problem with using HF is that it is dangerous both to people and to the environment.  A new method that has been developed to smooth the surface is pulse reverse electropolishing (EP). This method uses aqueous H2SO­­
4 as the electrolyte and alternating anodic and cathodic pulses to oxidize the niobium (Nb) and then remove the oxide from the surface [1]. Previous studies have shown that pulse reverse EP effectively polishes the surface of Nb SRF cavities [1,2].. In order to better understand polishing mechanism and optimize the operating parameter for cavity production, systematic electrochemical experiments have been carried out to further explore the oxide removal process, the effect of positive and negative pulse duration, pulse structure, off time between positive and negative pulses, concentration of H2SO­­
4, and determine optimum polishing parameters for reliable Nb SRF cavity production process, the results will be reported.
Ba0.5Sr0.5Co0.8Fe0.2O3-δ on N-Doped Mesoporous Carbon Derived from Organic Waste As a Bi-Functional Oxygen Catalyst
Authors: Wang Jian , Ciucci Francesco
Published: February 2020

Developing cost-effective oxygen electrocatalysts is critical to the wide application of renewable energy technologies including fuel cells, electrolyzers, and metal-air batteries. In this work, we report Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) on nitrogen-doped mesoporous carbon (NC) as a novel and highly-active bi-functional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The NC is prepared using organic waste, namely banana peels. The carbonization, heteroatom doping, and surface functionalization are achieved simultaneously during a facile synthesis process. The obtained NC is characterized by large mesopores with a specific surface area of 457.6 m2g-1. The electrochemical measurements reveal that, the current density of the BSCF/NC in 0.1 mol L-1 KOH reaches -3  at 0.74 V and 10  at 1.58 V vs. the reversible hydrogen electrode. Furthermore, the hybrid shows a smaller onset potential and larger current density towards both ORR and OER in comparison to composites made of BSCF and common commercial carbon supports, including acetylene black (AB) carbon, activated carbon (AC), and Vulcan XC-72 carbon. Besides enhancing the surface area and the dispersion of BSCF, the NC reduces the oxidation state of Co ion, likely giving the enhanced activity.
(Invited) Theoretical Analysis of Turbulent Mass Transfer with Rotating Cylinders
Authors: Newman John
Published: February 2020

The data of Eisenberg1 and of Mohr2 provide an excellent basis for examining mass transfer in the system where the inner cylinder rotates within a larger stationary cylinder.  The data are here correlated more carefully with respect to the dependence of the Stanton number on the Reynolds number, the Schmidt number, and the geometric ratio k of the inner cylinder radius to that of the outer cylinder.  Three methods are deployed in this endeavor.  Simple empiricism involves fitting the data according to the equation below where the parameters A, n, and p are functions of k.  Enlightened empiricism expands on the traditional method of fitting the eddy viscosity as a function of the distance from the wall in the form of y
+ = (y/n)(t0/r)0.5, where t0is the shear stress at the solid wall.  This method does not work well in a predictive manner for rotating systems or systems where the flow is in the direction of the curvature of the surface (as with Goertler vortices).  Dissipation theory relates the local dissipation to its generation, transport, and decay, involving a parameter for the decay constant of the dissipation.

The electrochemical data of Eisenberg (with 1-k values from 0.1723 to 0.871) seem to be in the regime of wide gaps, while Mohr focused on thin gaps (1-k ranging from 0.0172 to 0.0839) to explore the failure of Eisenberg’s data to show an expected behavior where thin gaps blend into turbulent Couette flow.  The dissipation theorem should provide a new method of understanding turbulent shear flow and a way of predicting the effect of varying the radius ratio.

*The author of this work is an Electrochemical Society Honorary Member

 

 

References

1. Morris Eisenberg, “Studies of Rates of Solid Dissolution and of Electrode Reactions at Rotating Cylindrical Bodies,” dissertation (Berkeley: University of California, 1953).

2a.  Charles Milton Mohr, Jr., Mass Transfer in Rotating Electrode Systems, dissertation (Berkeley: University of California, 1975).

2b.  Charles M. Mohr, Jr., and John Newman, Mass Transfer in Turbulent Flow between Rotating Cylinders with Small Separation Gaps.  Berkeley: Lawrence Berkeley Laboratory, 1976.  LBL-5136.  Apparently never published.

Figure 1
Electrochemical Characteristics of Garnet-Llzo Materials Doping By Chemical Elements for All Solid Lithium Batteries
Authors: Yang Seung-Hoon , Kim Min-Young , Kim Da-Hye , Kim Kyeong-Joon , Choi Seung-Woo , Noh Tae-Hyoung , Kim Ho-Sung , Lee Moo Sung
Published: February 2020

Recently, many sorts of lithium batteries have been studied such as all solid and lithium-air batteries etc., for EV and ESS applications. Especially, all solid battery is one of the candidates for a large-sized battery in regard of the safety problem. Garnet-type LLZO electrolyte has good advantages with a high ionic conductivity and electrochemical potential window. However, it is reported that there are difficulties to prepare LLZO(Li7La3Zr2O12) pellets with high relative density. In this study, LLZO material was doped by the different elements of Al, Nb, Ta by co-precipitation process. Furthermore, we studied the effects of lithium excess concentration of Al-doped LLZO. We investigated not only the change of cubic and tetragonal structure but also electrochemical properties according to the synthesis conditions. As a result, ionic conductivity of Al-doped LLZO material was about 3x10-4 S/cm at room temperature, indicating a wide electrochemical window of 0~5.5V. Furthermore, we will introduce the electrochemical properties of unit cell using LLZO material in more detail.
(Invited) All-Electronic Sensing of Single Molecule Dynamics Using Carbon Nanotube Devices
Authors: Collins Philip G.
Published: February 2020

Single-molecule techniques eliminate ensemble averaging to reveal the mechanisms, timing, and energetics of individual chemical and biochemical events.  Over the past decade, single-molecule science has flourished as new techniques have adopted fluorescent probes, optical traps, and scanning probe microscopy to access the single-molecule limit.  Recently, carbon nanotube transistors have been added to this toolkit of single-molecule techniques.  As electronic transducers, single-walled carbon nanotubes have the sensitivity to detect single molecular events [1] and the bandwidth to resolve microsecond-duration transients and intermediate states [2].  These characteristics provide exciting new opportunities to monitor and understand complex catalytic cycles such as the biochemical reactions of enzymes.

For example, the single molecule kinetics of the Klenow fragment (KF) of polymerase I have recently been studied by bioconjugating KF to nanotube transistors.  Continuous recordings of polymerase as it processes various DNA templates have extended through >10,000 bond-forming events, providing new insights into the processivity, kinetic variability, and tolerance of polymerase toward synthetic dNTP analogs [3,4].  In addition to the kinetics, signals generated with some analogs revealed conformational states that do not occur with native dNTPs, helping to explain polymerases’ tolerance for incorporating dNTP analogs.  The high resolution of the electronic records illuminate new aspects of polymerase’s catalytic cycle and suggest new opportunities for all-electronic DNA sequencing.

[1] Y. Choi, et. al., “Single-Molecule Lysozyme Dynamics Monitored by an Electronic Circuit,” Science
335, 319 (2012).

[2] M.V. Akhterov, et. al., "Observing Lysozyme Closing and Opening Motions by High-Resolution Single Molecule Enzymology." ACS Chemical Biology
10, 1495 (2015).

[3] T.J. Olsen, et. al., “Electronic Measurements of Single-Molecule Processing by DNA polymerase I (Klenow fragment),” JACS
135, 7855 (2013). 

[4] K.M. Pugliese, et. al., "Processive Incorporation of Deoxynucleoside Triphosphate Analogs by Single-Molecule DNA Polymerase I (Klenow Fragment) Nanocircuits." JACS
137, 9587 (2015).
Electrochemical Properties of Surface-Treated Hard Carbon Electrode
Authors: Ma Wen , Fukutsuka Tomokazu , Miyazaki Kohei , Abe Takeshi
Published: February 2020

Introduction

Li ion battery technology, since its birth in early 1990s, has been powering the rapid digitization of our daily life and finally applying to EVs and HEVs, resulting from its superior energy density compared to conventional rechargeable batteries. However, some improvements of this amazing energy storage system should be made in the future, in particularly, the enhancement of rate capabilities. The rate of lithium-ion batteries is influenced by several factors such as ion diffusion in the composite electrodes, charge transfer resistances, diffusion in the active materials, etc. Among them, we have paid much attention on the charge transfer resistances. According to the Arrhenius equation, the charge transfer resistances are inverse proportion to the frequency factor and exp(-Ea/RT), where Ea, R, and T denote to the activation energy, gas constant, and absolute temperature. Therefore, the decrease of the charge transfer resistances can be made by the increase of the frequency factors and the decrease of Ea. As for the negative electrodes of commercial lithium-ion batteries, graphite electrodes have been mainly used. Hard carbon electrodes have been also used in HEVs since the rate performance is superior to that of graphite. This should be principally resulted from the large frequency factors. Then, we have focused on the surface treatment of hard carbon electrodes to decrease the activation energy of Ea. Here, we report the electrochemical properties of surface-treated hard carbon electrodes by Li3PO4.

Experimental

Glassy carbon electrodes were used as model electrodes in this study. In advance, the glassy carbon electrodes have been heat-treated at 773 K in the air for 1 h. Surface treatment of the glassy carbon electrodes were made by the sputtering of Li3PO4 in several conditions. Three-electrode cell was fabricated by using surface-treated glassy carbon electrode as a working electrode and lithium metal for counter and reference electrodes. Electrolyte solution was 1 mol dm-3 LiClO4/ EC + DEC (1:1). Cyclic voltammograms were conducted with a potential rage of 0 – 3 V at a scan rate of 0.1 mV/s. Ac impedance spectra of the glass carbon electrodes were measured at given potentials and temperatures.

Results and discussion

Cyclic voltammograms (Fig. 1) of the surface-treated glassy carbon showed the large reductive and oxidative currents which corresponded to the insertion and extraction of lithium-ion at the electrode, respectively. In addition, it was found that the surface-treatment enhanced the glassy carbon electrode properties by comparing the pristine one. In the Nyquist plots at different potentials, various semi-circles were seen. Assignment of each semi-circle will be discussed in the conference.

Figure 1
Investigation of Solid Electrolyte Interface Formation in Li3as Electrode Material in a Solid-State Battery Configuration
Authors: Samuthira Pandian Amaresh , Hood Zachary D. , Wang Hui , Liang Chengdu , Dudney Nancy J
Published: February 2020

Solid state batteries have gained attention due to the promise of safe operation of battery at high voltage and for longer duration. Solid electrolytes may also help to stabilize conversion electrodes for higher energy density. Arsenic alloys are rarely studied, but several may be interesting as the negative electrode, for example, FeAs, As/C, and InAs.1 The fact that the cost per pound of Arsenic is less than the counterpart negative electrode candidates like Si, Ge, In, Pb, Ti, and V is advantageous.2

In this context, we chose Li3As as a negative electrode material in a solid-state battery configuration. The intrinsic high electronic conductivity of Li3As and conversion reaction mechanism providing a high energy density are the reasons behind selecting Li3As for studying the cycling and interface stability with a Li-P-S based solid electrolyte. The solid-state battery was cycled at different temperatures and the resultant pellet was dissected for analyzing the interface layer formed. The battery that has the iodide doped solid electrolyte performed well in terms of electrochemical cycling properties compared to the undoped electrolyte. An iodide rich layer between the solid electrolyte and Li3As electrode formed within few cycles. This thin iodide rich layer is responsible for the stable performance of the solid-state battery for over 100 cycles.

Acknowledgement: This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U. S. Department of Energy under the Advanced Battery Materials Research Program. Synthesis of the electrolyte was conducted as part of user proposal at ORNL’s Center for Nanophase Materials Sciences (CNMS), which is an Office of Science User Facility.

References:

(a) J. Chen, H. Zhao, N. Chen, X. Wang, J. Wang, R. Zhang, and C. Jin, J. Power Sources, 200, 98 (2012); (b) X. Lia, D. Xiao, H. Zheng, X. Wei, X. Wang, L. Gu, Y.-S. Hu, T. Yang, and Q. Chen, Nano Energy, 20, 194(2016); (c) C.-M. Park, J. Solid State Electrochem., 20, 517 (2016).

N. Nitta and G. Yushin, Part. Part. Syst. Charact., 31, 317 (2014).

*Corresponding author email: dudneynj@ornl.gov
Titanium Dioxide As a High Capacity Anode for High Voltage Aqueous Lithium-Ion Batteries
Authors: Ramanujapuram Anirudh , Gordon Daniel , Coffman Keith , A. Sosa Ramón , Zhang Shuchen , Yushin Gleb
Published: February 2020

Aqueous lithium-ion batteries are gaining increasing interest as a potential candidate for the next generation batteries. These batteries provide much higher safety and reduced cost of manufacturing as the prime advantages. Aqueous electrolytes also offer higher ionic motilities for lithium ions which could pave the way for faster charging batteries.

Despite the advantages, a huge drawback in aqueous batteries is the lower electrochemical stability window for water-based electrolytes. Titanium dioxide (TiO2) is one candidate electrode material that can offer a high capacity, but the redox potential for TiO2 is much lower than the hydrogen evolution potential for water.

Here we report on our efforts to increase the over-potential for hydrogen evolution on the anode in order to achieve good cycle stability of TiO2 in aqueous electrolytes. By using a combination of in-situ and ex-situ surface coatings on the anode and tuning the composition and molarity of aqueous electrolytes, we demonstrate that the over-potential for hydrogen evolution can be suppressed to sufficiently low potentials to allow reversible Li insertion and extraction to/from TiO2. These achieved results are critically important for the development of high voltage aqueous batteries.

Materials characterization of TiO2 electrodes using scanning and transmission electron microscopy (SEM and TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction and vibrational spectroscopy studies (Raman and FTIR) before and after electrochemical cycling will be reported. Results of electrochemical characterization tests, such as cyclic voltammetry (CV) conducted at different sweep rates, charge-discharge (C-D) conducted at different current densities and different temperatures and electrochemical impedance spectroscopy (EIS) studies, show the relationships between the composition of cell components and cell electrochemical performance.
Characteristics of Double Layerd TiO2 Cathode Assembling to Marine Microbial Fuel Cell
Authors: Motoda Shinichi , Morita Motoaki , Tamura Sho
Published: February 2020

For these recent several years, biomass, geothermal, wind power, and the solar power becomes the urgent issues from a development demand that arise from global environment such as the running out crisis of the fossil fuel. However, there are not so many electric power generation systems in conjunction with the ocean accounting for 70% of the surface area of the earth. In the present work, we tried it using marine environment and solar for the purpose of improving a performance of the biofilm battery which was one of the microbial fuel cells (MFC).

The biofilm formed to a cathode electrode ennoble the electrode potential and the photocatalytic effect of the TiO2 film coated metal surface of an anode electrode makes it possible to be an renewable energy source.

However, we are not yet put it to a practical use by a reason such the lack of stability in the photocatalytic effect of the titanium dioxide coated on to the stainless steel anode by a plasma spraying technique. Therefore, in this study, we aimed to improve the photocatalytic activity of the anode electrode by developing the electrode which layered titanium dioxide by two phases using the the squeegee method and a plasma gas arc spraying method by improving those properties in the biofilm battery.

As a result of measured electrode potential of the TiO2 electrode, following results were obtained;

1) The photocatalytic potential of the TiO2 single-layered electrode showed -0.63V (SCE). This made the electrode potential lower 0.13V than that of an electrode conventionally, and improvement of the photocatalytic activity. In addition, reproducibility and stability were observed in the time variations of photo potential. When this electrode assembled in a biofilm battery, the open circuit voltage rose 0.09V in comparison with a battery conventionally, and the maximum power increase 1.33 times enabled.

2) The output of the biofilm battery which assembling double layer TiO2 anode electrode rose 1.81 times electric power in comparison with previous one. It is thought that the electron which moves from the anatase outer layer to substrate stainless steel through the rutile intermediate layer accelerated by the heterojunction effect at the anatase / rutile interface.
Enhancing the Kinetics of Lithium/Sodium Transition Metal Orthosilicate Cathodes through Tuning the Crystallographic Habits
Authors: Ding Zhengping , Ivey Douglas G , Wei Weifeng
Published: February 2020

Lithium transition metal orthosilicates, Li2MSiO4 (M=Mn, Fe, Co), have received great attention because of the theoretical possibility to reversibly deintercalate two Li+ ions from the silicate structure. However, the silicates still suffer from low electronic conductivity, sluggish lithium ion diffusion and poor structural integrity upon electrochemical cycling. Recently, sodium transition metal orthosilicates, Na2MSiO4 (M=Mn, Fe, Co), have been reported to be used as a cathode material for sodium secondary battery. In this research, lithium/sodium transition metal orthosilicate A2MSiO4 (A=Li or Na; M= Mn, Fe or Co) nanostructures with preferential exposures of various crystallographic planes on the surface were synthesized via a facile and efficient solvothermal process. Detailed microscopic and spectroscopic analyses are performed to get a better understanding of the electrochemical performance-structure correlations in the crystal habit-tuned A2MSiO4 nanostructures. We anticipate that this novel strategy should shed light on the design and development of a wide range of high capacity intercalated cathode materials for lithium/sodium ion batteries.
Development of a Lower Temperature Operating Sodium Beta-Alumina Battery (LT-NBB): Strategies and Technical Challenges
Authors: Jung Keeyoung , Park Yoon-Cheol , Cho Namung , Son Sori , Lee Younki , Kim Chang-Soo , Kim Goun , Jin Dana , Shim Wooyoung , Li Guosheng , Sprenkle Vincent
Published: February 2020

The sodium nickel chloride (Na/NiCl2) battery is one of the most promising candidates for a large scale electrochemical energy storage device. The battery comprises NiCl2 and molten Na as positive and negative electrodes in its charged state, and uses a Na+ ion conducting β"-Al2O3 solid electrolyte (BASE) to separate the cathode and anode. In order to facilitate fast sodium ion transport in the cathode compartment, molten NaAlCl4, as a secondary electrolyte (or catholyte), is infiltrated into the powdered cathode material. The battery typically operates at 250~300°C to maximize the ionic flux in the NaAlCl4 and through the solid electrolyte, and to minimize the dissolution of NiCl2into the melt. However, this efficient battery has yet to be widely used in grid scale energy storage applications, since it is still expensive; it is difficult to dramatically reduce the cell price in its present form mainly due to its use of expensive sealing technologies.

The presentation introduces U.S.-Korea collaborative efforts to develop a sodium beta-alumina battery with a Na/NiCl2 chemistry that operates at a lower temperature. Since the novel battery runs below 200°C, it can be fabricated at an ultralow manufacturing cost by (1) introducing a new planar cell design with a greatly reduced number of cell components, and (2) eliminating expensive sealing technologies. Enhanced degradation resistance of cathode materials is another important advantage of this technology. This presentation will start by stating problems found in traditional sodium beta-alumina batteries, and our strategies to resolve the issues will be described. Technical challenges and progress in materializing prototype LT-NBB cells and related core technologies will be briefly discussed, which include cell design, a highly toughened BASE, an enhanced wetting agent, and an inexpensive sealing method.
The Re-Discovery of Scandium-Substituted Na3Zr2(SiO4)2(PO4)
Authors: Ma Qianli , Guin Marie , Naqash Sahir , Tsai Chih Long , Tietz Frank , Guillon Olivier
Published: February 2020

In recent years, the requirement of energy storage for renewable clean energy, like solar and wind energy, has attracted more and more interest of the relevant research globally. As one of the choices, room-temperature Na-ion batteries (NIBs) show advantages of unlimited sources, low price of starting materials and easy recycling,[1] which promise them high potential for energy storage applications. NIBs in all-solid-state design are regarded as the batteries of the next generation because of their non-leakage, non-volatilization, non-flamma­bility, separator-free design and adaptability to temperature changes.[2] Trivalent-cation-substituted Na3Zr2(SiO4)2(PO4)3 in NASICON structure are regarded as promising electrolyte materials for all-solid-state NIBs because of their high Na-ion conductivity and reliable chemical and physical stability. In this study, scandium is chosen as the substitution element for Na3Zr2(SiO4)2(PO4) (Sc substituted Na3Zr2(SiO4)2(PO4)3, NSZSP), because among all the trivalent cations, the ionic radius of Sc3+ (74.5 pm) is the closest to that of Zr4+ (72.0 pm), indicating that the substitution only generates a deficiency in positive charge, but does not cause distortions in the crystal structure. NSZSP has received hardly any attention so far. Only one reference reported this kind of materials.[3] However, the reference mainly targeted the performance of NSZSP at high temperatures (~300°C). Only a few conductivities at room temperatures were mentioned, and they are rather moderate (maximum 5.0 × 10-4 S cm-1). In this study, a solution-assisted solid-state reaction method was invented by which a series of NSZSP nano-powders with favorable microstructures were prepared. With increasing of scandium substitution, the conductivity of sintered NSZSP samples also increases. Na3.4Sc0.4Zr1.6(SiO4)2(PO4) shows the highest conductivity of the system so far, more scandium substitution decreases the conductivity because there exists a most suitable ratio between occupied and vacant Na sites. The total-ionic conductivity of Na3.4Sc0.4Zr1.6(SiO4)2(PO4) reaches 4.0 × 10-3 S cm-1 at 25 °C. To our knowledge, it is not only the best value for all materials with NASICON type structure, but also the best reported value for all polycrystalline oxidic Na-ion conductors. It is even comparable with common liquid electrolytes of NIBs. The possible reason for such high conductivity is discussed in specific.

[1] D. Larcher, J. M. Tarascon, “Towards greener and more sustainable batteries for electrical energy storage”, Nat Chem
2015, 7, 19-29.

[2] A. Hayashi, K. Noi, A. Sakuda and M. Tatsumisago, “Superionic glass-ceramic electrolytes for room-temperature rechargeable sodium batteries”, Nat. Commun. 2012, 3, 856-861.

[3] M. A. Subramanian, P. R. Rudolf and A. Clearfieled, “The Preparation, Structure, and Conductivity of Scandium-Substituted NASlCONs”, J. Solid State Chem. 1985, 60, 172-181.
Simultaneous Analysis of Thin-Film Manganese Dioxide Deposits Using Eqcm, Cyclic Voltammetry, Step Potential Electrochemical Spectroscopy and Electrochemical Impedance Spectroscopy
Authors: Donne Scott W , Cameron Hayden
Published: February 2020

As a population the reliance on portable electronics and rapid development in electric vehicles in order to combat global warming has caused researchers to search for materials that exhibit excellent energy storage properties. Thin film MnO2 deposits have been observed to exhibit these properties and has become a popular research material for capacitors and batteries.

In this project a method was developed in which the mass change for a thin film of MnO2 during electrochemical experiments could be observed. It was conducted by depositing MnO2 onto a platinum quartz crystal, by doing this it allowed for the mass change throughout the deposition process to be recorded providing a better understanding of the deposition mechanism. Once the MnO2 was deposited the EQCM was used as a working electrode throughout further electrochemical testing which included cyclic voltammetry (CV), step potential electrochemical spectroscopy (SPECS), and electrochemical impedance spectroscopy (EIS) while recording the mass change throughout each test.

Cyclic voltammetry was conducted with a 25mV sweep from 0 - 0.8V for 250 cycles. By doing this the capacitive performance of the material was determined, however, by recording the mass change throughout the experiment it was possible to determine if there were faradaic, non-faradaic process occurring on the surface of the electrode affecting the charge storage mechanism and to observe sample stability throughout cycling.

SPECS and EIS immediately followed the cycling which allowed for the observation of the maximum charge storage capability of the material and the mechanism in which the material stores energy. The impedance data allows for the analysis of the charge transfer mechanism and the various interfacial resistance and capacitance at the electrode-electrolyte interface.

This technique has allowed for significantly greater understanding of the processes that the electrode materials are undergoing throughout the experiments and can be used as a powerful tool in various aspects of electrochemical analysis.

Figure 1
A Novel Rapid Processing Route to Sintered Plaque Aqueous Nickel Electrodes for Low Cost Building Scale Energy Storage
Authors: Marinaccio Jordan Domonic , Glover Carol Frances , Subramanian Raman , Barnes Alistair David , Williams Geraint , Elvins Jonathon
Published: February 2020

Electrification of heating systems and transportation as well as decarbonisation of electrical energy production will continue to place more and more stress and strain on current electrical grid infrastructures. Renewable energy generation technologies such as photovoltaics and wind power generation are seen by many as the future for energy production and security. With high dependence on such intermittent and ‘highly distributed micro-generation’ energy production technologies, ‘highly distributed micro-storage’ solutions such as secondary batteries could prove to be the answer. An appropriate technology would ideally possess a lifetime in-line with current photovoltaic technologies (20 years), be inherently safe and be able to cope with the unpredictable cycling conditions posed by intermittent generation and user demand.

One such technology, namely nickel-iron aqueous batteries (pioneered by Thomas Alva Edison in 1901) boasts cycle life in excess of 5000 cycles, as well as tolerance of both physical and electrical abuse. Low energy density (both gravimetrically and volumetrically) are long standing issues with the chemistry, however given the nature of the application, such issues are not of the greatest concern.

The greatest issue posed by the nickel cathode material is the poor high rate charge/discharge capability, due to the insulating nature of nickel hydroxide active materials. This can be addressed by configuring the cathode active material within a conductive scaffold (sintered nickel plaque on nickel-plated steel current collector). This does however hinder manufacturability of the cathode, requiring a highly energy intensive heat treatment (900oC, 30 minutes). Herein we evaluate electrodes produced via 2 process routes: - A traditional process route consisting of a slurry deposition and subsequent convection sintering process and a continuous current active material deposition process, versus a novel rapid process route, utilising high volume throughput screen printing of both nickel and titanium dioxide scaffolds and Near Infrared rapid curing technology, as well as a pulsed current active material deposition. The latter results in a substantial reduction in manufacture time, opening the door to semi-continuous processing for sintered nickel battery technologies and therefore low-cost energy storage.
Electrochemical Modeling, Optimization and Control of Lithium Metal Batteries
Authors: Lee Seong Beom , Kolluri Suryanarayana , Xu Wu , Zhang Ji-Guang , Subramanian Venkat R.
Published: February 2020

Li metal is receiving great attention in recent years as an anode material. It has the lowest negative electrochemical potential (-3.040V vs. SHE), a low gravimetric density (0.534 g∙cm-3), and an extremely high theoretical specific capacity (3860 mAh∙g-1) compared to graphite (372 mAh∙g-1) used in Li-ion batteries1. Most available battery models, however, focus on the performances of Li-ion batteries, which are not good enough to predict the behavior of Li metal batteries and even Li metal battery models that are used today do not account for the internal states of the battery system2.Therefore, development of a simulation model to explain the unique feature of Li metal batteries will be critical in this field and will largely accelerate the development of rechargeable Li metal batteries.

The control of the charge/discharge rate which is very critical for the long-term stability of Li metal batteries has been recently developed by Zheng et al3. The key aims in this presentation include: (1) development of multiscale models that will provide optimal charge/discharge controls to enhance the lifetime of Li metal batteries, (2) electrochemical characterization to validate the predicted improvement in life/performance.

 

Acknowledgements

The authors acknowledge financial support from the University of Washington’s Clean Energy Institute and Washington Research Foundation.

 

References

1. J. Qian, W. A. Henderson, W. Xu, P. Bhattacharya, M. Engelhard, O. Borodin and J.-G. Zhang, Nature communications, 6 (2015).

2. Z. Li, J. Huang, B. Y. Liaw, V. Metzler and J. Zhang, Journal of power sources, 254, 168 (2014).

3. P. Y. Jianming Zheng, Donghai Mei, Mark H. Engelhard, Samuel S. Cartmell,Bryant J. Polzin, Chongmin Wang, Ji-Guang Zhang, and Wu Xu, Advanced Energy Materials, 1502151 (2016).
Effect of Membrane Type of the Performance of a Hydrogen-Vanadium Flow Battery
Authors: Nguyen Trung Van , Dowd Regis Paul , Wycisk Ryszard , Pintauro Peter N.
Published: February 2020

Hydrogen-vanadium flow batteries offer a feasible solution for storing electrical energy from the grid or directly from renewable energy sources such as wind and solar. Vanadium systems demonstrate no issues with membrane fouling or metal dendrite formation. Additionally, vanadium solutions have low volatility and low corrosivity. Due to the relatively high cost of vanadium ($ per kg), the hydrogen-vanadium flow battery is attractive over the all-vanadium system due to the 50% reduction in the amount of vanadium solution required. Furthermore, by replacing the negative vanadium electrode with a hydrogen electrode the effect of self-discharge by the crossover of unwanted ions, mostly the smaller vanadium II and III ions, is expected to be greatly reduced. In this presentation, the performance of electrospun perfluorosulfonic acid (PFSA)/polyphenylsulfone and PFSA/polyvinylidene fluoride (PVDF) composite membranes, relative to PFSA membranes such as Nafion, with regards to the self-discharge rate and electrical performance of a hydrogen-vanadium flow battery will be discussed.

Acknowledgement

The work presented was partially funded by the National Science Foundation under Grant No. EFRI-1038234
Rde Kinetic Study of V(IV)/V(V) and V(II)/V(III) Reactions on Thermally Activated and Non-Activated Carbon Felts
Authors: Li Yue , Parrondo Javier , Ramani Vijay K
Published: February 2020

Graphite felt is the most common electrode material used at both the cathode and the anode in vanadium redox flow batteries (VRFBs). Graphite felt exhibits good activity towards the redox reactions, has a wide operational potential range, and exhibits stability in acidic environments. A variety of studies have been conducted to investigate the effects of different felt pre-treatment methods for on VRFB performance (1, 2). Basically the pre-treatment methods can be categorized into oxidation and reduction of the graphite felts. Even though this field has been extensively studied by using different techniques, there is still some controversy. It is commonly accepted that chemical/electrochemical oxidation of graphite felts increases their activity towards V(IV)/V(V) reactions (3, 4). However, there are few studies reporting the opposite result (5, 6). It is therefore necessary to perform a fundamental study of the kinetics of vanadium species redox reactions on activated and non-activated graphite felts.

The felt material (non-activated or activated) was ground using a mortar and mixed with epoxy resin to form a paste (33wt% of epoxy). The paste was pressed (8000 kg/cm2) in a stainless steel mold until it hardened, and the resultant electrode was employed as the disk in the rotating disk electrode experiments (RDE). To our best knowledge, this is the first RDE study of vanadium reactions on non-activated and activated graphite felts. The results and trends obtained in the RDE studies were verified by performing vanadium flow battery experiments. The presentation will discuss how the RDE disk was made, present the kinetic data of non-activated graphite felt and thermally activated (7) graphite felt for both V(IV)/V(V) and V(II)/V(III) redox reactions. The kinetic analysis will be accompanied with the analysis of the carbon felts by scanning electron microscopy, X-ray photoelectron spectroscopy, and charge/discharge curves in an all-vanadium redox flow battery.

References 

1. W. G. Zhang, J. Y. Xi, Zhaohua Li, H. P. Zhou, L. Liu, Z. H. Wu, and X. P. Qiu, Int. J. Electrochem. Sci., 4700 (2013).

2. X. G. Li, K. L. Huang, S. Q. Liu, N. Tan, and L. Q. Li, Trans. Nonferrous Met. Soc. China, 17, 195 (2007).

3. Y. Men and T. Sun, Int. J. Electrochem. Sci., 3482 (2012).

4. L. Yue, W. S. Li, F. Q. Sun, L. Z. Zhao, and L. D. Xing, Carbon, 3079 (2010).

5. A. Bourke, M. A. Miller, R. P. Lynch, J. S. Wainright, R. F. Savinell, and D. N. Buckley, J. Electrochem. Soc., 162, A1547 (2015).

6. A. Bourke, M. A. Miller, R. P. Lynch, X. Gao, J. Landon, J. S. Wainright, R. F. Savinell, and D. N. Buckley, J. Electrochem. Soc., 163, A5097 (2016).

7. B. Sun and M. Skyllas-Kazacos, Electrochim. Acta, 37, 1253 (1992).
Effect of Carbon Substrate Pretreatment on the Ecsa and Activity of RhxSy/C Catalyst
Authors: Li Yuanchao , Nguyen Trung Van
Published: February 2020

Electrical energy storage technologies are needed when significant fraction of intermittent renewable energy sources such as wind and solar are integrated into the electrical grids. The hydrogen-bromine (H2-Br2) reversible fuel cell system is one of the promising technologies because of its high round-trip conversion efficiency, high power density capability and low cost. In a hydrogen bromine fuel cell, while carbon can be used for the bromine reactions, a noble metal such as platinum is needed for the hydrogen reactions. Since platinum is not stable in HBr/Br2 environment and HBr and Br2 are expected to cross from the bromine electrode to the hydrogen electrode during operation, a more durable and active catalyst is needed for the hydrogen reactions. RhxSy catalysts have been found to be stable in the HBr/Br2 environment and as active as platinum per active area. 1,2

Commercial RhxSy catalysts have large and broad particle sizes (12-40 nm) and consequently low mass specific active area (< 10 m2/g) for HOR. By literatures3,4, smaller particle size can be achieved if more preferable surface for precipitation of Rh cation is provided. Figure 1 shows the mass specific active surface area (ECSA) of the catalyst with pretreated carbon and commercial RhxSy catalysts. It shows that the RhxSy catalyst with pretreated carbon material has much higher mass specific ECSA than commercial RhxSy. This presentation will discuss the approach used to synthesis the RhxSy catalyst with pretreated carbon and the characteristics and performance of this catalyst.

 

Figure 1. CV of catalyst with pretreated carbon and commercial
one
, measured in 1M H2SO4 with 10 mV/s scan rate

 

 

References

 

 1. J. Masud, T. Van Nguyen, N. Singh, E. McFarland, M. Ikenberry, K. Hohn, C. J. Pan and B. J. Hwang,,, Journal of the Electrochemical Society, 162, F455–F462 (2015).

2. A. Ivanovskaya, N. Singh, R.-F. Liu, H. Kreutzer, J. Baltrusaitis, T. Van Nguyen, H. Metiu and E. McFarland,, Langmuir, 29, 480–492 (2013).

3. A. Eguizabal, L. Uson, V. Sebastian, J. L. Hueso, and M. P. Pina, RSC Advances, 5, 90691–90697 (2015).

4. M. S. Shafeeyan, W. M. A. W. Daud, A. Houshmand, and A. Shamiri, Journal of Analytical and Applied Pyrolysis, 89, 143–151 (2010).

Acknowledgements

The work presented herein was funded by the National Science Foundation under Grant No. EFRI-1038234.

Figure 1
Development Strategy and Comparison of a Novel Flow Field Design for Redox Flow Battery
Authors: Fofana Daouda , Roberts Edward
Published: February 2020

Novel cathode electrode flow field design for redox flow batteries (RFBs) have being developed to provide high performance compared to the serpentine flow field. A three-dimensional steady state model accounting for mass, momentum, species, electrochemical reactions and charge conservation equations have been developed. The species concentration, the mass fractions distribution, the velocity and the pressure distribution have being carried out and compared. A parametric study was performed to highlight the effect of different parameters such as porosity, thickness, active surface area as well as the permeability.
A High-Performance Asymmetric ZnO/α-Fe2O3//ZnO/C Supercapacitor with Core-Shell Nano-Rods
Authors: Sarkar Debasish , Shukla Ashok Kumar , D. Sarma D.
Published: February 2020

A core-shell design for nanostructured electrode materials is introduced for realizing high-performance supercapacitors. In the proposed core-shell design, thin shell-layers of highly electroactive/pseudo-capacitive materials provide the platform for surface or near-surface based faradaic/non-faradaic reactions together with shortened ion-diffusion path facilitating fast-ion intercalation/deintercalation processes, while the highly-conducting core serves as highway for fast electron/ion transfer towards current collector, improving energy and power performance characteristics of the core-shell structure in relation to pristine component materials. Moreover, use of carbon (C)-based materials as shell layer in either electrode not only enhances capacitive performance through double-layer formation but also provides enough mechanical strength to sustain volume changes in the core material during long-cycling of the supercapacitor improving its calendar life. In such an effort, both the negative and positive electrodes, namely ZnO/α-Fe2O3 and ZnO/C core-shell nano-rods of the assembled asymmetric supercapacitor (ASC) exhibit significant improvement in electrochemical performance in terms of the specific capacitance and rate capability as compared to pristine α-Fe2O3, ZnO and C electrodes. Such an ASC exhibits a specific capacitance of ~115 F/g at a scan rate of 10 mV/s in a potential window as high as 1.8V with response time as low as ~ 39 ms and retains more than 80% of its initial capacitance after 4000 cycles. Interestingly, the ASC can deliver an energy density of ~ 41 Wh/kg and a power density of ~ 7 kW/kg that are significantly higher than those reported hitherto for iron-oxide-based ASCs.
The Characteristics of Non-Aqueous Redox Flow Battery Using Organic Materials
Authors: Shin Kyoung-Hee , Park Se-Kook , Jin Chang-Soo , Yeon Sun-Hwa , Lee Bum suk
Published: February 2020

The redox flow battery (RFB) has been considered to be one of the most promising electrical energy storage system with large-scale applicable, owing to its attractive features such as flexible design, high safety and high efficiency [1-3]. Despite significant advances, the operating potential of such aqueous RFBs are generally limited by the electrochemical stability window of water, and hence low energy density is obtained [4-6]. In contrast, non-aqueous RFBs have been receiving increasing interest given that non-aqueous electrolytes offer the possibility of wider potential windows. Therefore, non-aqueous RFBs have attracted considerable attention [7,8].

In this work, all-organic redox couples (metal-free organic materials) were used as a negative and a positive electrolyte, respectively. From cyclic voltammetry tests, it was confirmed that a non-aqueous redox system yielded an estimated high potential at a 50% state of charge, and electrochemical test appeared to be stable and reversible.

Reference

[1] Z. Yang, J. Zhang, M.C. Kintner-Meyer, X. Lu, D. Choi, J.P. Lemmon, J. Liu, Chem. Rev., 111 (2011) 3577-3613.

[2] B. Dunn, H. Kamath, J.-M. Tarascon, Science, 334 (2011) 928-935.

[3] C. Koroneos, T. Spachos, N. Moussiopoulos, Renewable energy, 28 (2003) 295-310.

[4] M. Skyllas-Kazacos, M. Chakrabarti, S. Hajimolana, F. Mjalli, M. Saleem, Journal of The Electrochemical Society, 158 (2011) R55-R79.

[5] A.Z. Weber, M.M. Mench, J.P. Meyers, P.N. Ross, J.T. Gostick, Q. Liu, Journal of Applied Electrochemistry, 41 (2011) 1137-1164.

[6] P. Leung, X. Li, C.P. De León, L. Berlouis, C.J. Low, F.C. Walsh, Rsc Advances, 2 (2012) 10125-10156.

[7] J. Mun, M.-J. Lee, J.-W. Park, D.-J. Oh, D.-Y. Lee, S.-G. Doo, Electrochem. Solid-State Lett., 15 (2012) A80.

[8] Z. Li, S. Li, S. Liu, K. Huang, D. Fang, F.Wang, S. Peng, Electrochem. Solid-State Lett., 14 (2011) A171.
Polyimide-Wrapped Carbon Nanotube As High Capacity and Rate Anode for Aqueous Rechargeable Na-Ion Batteries
Authors: Lim Hana , Cho Bo-Young , Lee Ho-Nyun , Lee Min-Hyung , Kim Hansung , Kim Hyun-Jong
Published: February 2020

Rechargeable lithium-ion batteries (LIBs) are rapidly extended from portable device to electric vehicle and smart grids owing to their high energy density and long cycling life. However, its potential for large-scale applications in electric vehicles and energy storage is hampered by the high production costs and finite supply of lithium. With this background, an attractive approach to circumvent this problem is to use an aqueous electrolyte for Na-ion batteries (NIBs). Researchers hope to overcome this problem by replacing it with sodium, which is cheaper, nontoxic, and easier to process and almost infinitely abundant.

In this study, pyromellitic dianhydride (PMDA)-derived polyimide deposited on the carbon nanotubes were used as anode of aqueous electrolyte battery. That is, polyimide was directly polymerized on the surface of CNT. SEM and TEM revealed that the polyimide was homogeneously wrapped the surface of the CNTs and formed a uniform shell. This suggests that the interactions between polyimide molecules and CNTs overcame the Van der Waals interaction between CNTs, which generally otherwise would result in separate growth or aggregates of polyimide.

The charge-discharge characteristics were investigated by using 3-electrode beaker cell with 2M Na2SO4 solution. The reduction and oxidation of polyimide are accompanied by the association and disassociation of Na+ ions with oxygen as described in Fig. 1. Each formula unit is able to transfer four electrons through two steps, which may allow a high theoretical specific capacity, 280.4 mAh g-1. The polyimide-wrapped carbon nanotube exhibited much superior high-rate and long cycling performance to conventional inorganic anode. The calculation of diffusion coefficient and impedance study revealed that these high performances were attributed to the advantages of hierarchical core-shell structure. The conductive CNT core offered continuous electron transport pathways and thin polyimide shell provides rapid Na+ ion diffusion pathways. Thus, the bicontinuous electron/ion transport channel greatly facilitate the ion diffusion kinetics and reduce the charge transport resistance, resulting in the excellent rate capability.

Figure 1
(Keynote) Recent Progress in Nanoscale Understanding of Surface Oxide Film Formation, Properties and Breakdown on Metals and Alloys Using in Situ and Ex Situ Characterization Methods
Authors: Marcus Philippe
Published: February 2020

After a short historical introduction in recognition to the pioneering work of Masahiro Seo, recent advances in the understanding at the nanoscale of the formation, properties and breakdown of oxide films on metals and alloys will be presented, with emphasis on data obtained using advanced in situ and ex situ surface analytical techniques such as Scanning Tunneling Microscopy (STM), Scanning Tunneling Spectroscopy (STS),Current-Sensing Atomic Force Microscopy (CS-AFM), X-ray Photoelectron Spectroscopy (XPS), and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), combined with electrochemical measurements, and complemented by atomistic modelling with Density Functional Theory (DFT).

The following topics will be addressed:

Nanostructured oxide layers formed by controlled thermal oxidation of copper single crystal surfaces

Passive oxide films for corrosion protection of metals and alloys: crystallinity, oxide/metal epitaxy, effects of time of polarization on oxide crystallinity, compositional heterogeneity of surface oxides (in the case of stainless steel)

Role of surface oxide defects in passivity breakdown and initiation of localized corrosion, investigated with high resolution

Oxide layers deposited by ALD (Atomic Layer Deposition) for corrosion protection, and as model systems for the study of conversion-deconversion mechanisms in Li-ion batteries

Atomistic modelling of oxide layers on metals using density functional theory (DFT)