bluuebunny/crossref_metadata_2025 huggingface dataset:
Molten Salt Electrorefining of Indium Metal from Indium Tin Alloy
Authors: Choi Sang-Hoon , Ali Basit , Hyun Soong-Keun , Sim Jae-Jin , Ju Won , Lim Jae-Hong , Kim Taek-Soo , Park Kyoung-Tae
Published: February 2020

Indium is an essential element for the fabrication of transparent conductive oxide (TCO) materials. However, it is very rare element and is obtained as a byproduct of zinc metal refining. Moreover, its recycling rate is less than 1%. This provokes the need to recycle indium from its end products. Indium and tin (Sn) are especially well suited for molten salt electrolysis because of their low melting points. In this paper, reduction processes on molybdenum electrode at 500oC in molten LiCl–KCl eutectic (55.7-44.3 mol %) containing varying amount of InCl3 was studied by Cyclic Voltammetry (CV) and Chronopotentiometry (CP). In-Sn alloy was used as raw material. Thermodynamic calculations showed poor stability of InCl3 with metal based crucibles. So, Al2O3 crucible was utilized for the experiments. Concentration of InCl3 was changed from 1 wt% to 3 wt% and it was found that the reduction of indium ions take place by a two-step electrochemical reaction: In3+/In+ and In+/Ino
at the potentials of 0.78 and 0.24 V versus Ag/AgCl. Number of transferred electrons and diffusion coefficient of In+3 ion species in molten salt with varying InCl3 content was estimated with the help of CV measurements. However, at 500oC, InCl3 shows chemical reactivity with Sn metal according to the following reaction: InCl3 + 1.5Sn → 1.5SnCl2 + In. This problem was overcome by shifting the molten chloride system to molten fluoride system (LiF-KF-InF3) as fluoride based salts shows high chemical stability with metals. As a result of electrorefining, In-Sn alloy was recycled into pure indium with low levels of impurities.
Application of Iron Based Alloy Electroplating to Environmental Friendly Industries-Hydrogen Generator
Authors: Yoshihara Sachio
Published: February 2020

Hydrogen energy system by use of water electrolysis under sustainable energy, hydro and solar power have much attention because of CO2 free, environmentally friendly zero emission system, itself. There exist the business chance, such as energy storage system to fit the demand for hydrogen stations oriented to FCV.

The development of technology to produce low-cost, large amounts of hydrogen has not been matured yet. So the research and development of the electrode for alkaline water electrolysis were important. The aim of this study is the development of the cathode with high catalytic activities and high corrosion resistance by use of electroplating process. We have already reported the performance of electrodeposited Ni-P, Ni-W-S or Ni-W-P electrode for alkaline water electrolysis. In this report we have finally found the best electrodeposited cathode, Fe-Ni-W. The characteristics for alkaline water electrolysis have been tried by linear sweep voltammetry (LSV), etc.

Alloy plating has been accomplished using electrochemical measurement system. The bath for electroplating consist of FeSO₄, NiSO₄, Na₂WO₄, H₃BO₃, H₃Cit, Na₃Cit. The substrate for plating (working electrode) was stainless steel substrate (SUS430). Before plating the substrate was washed with water and finished with nickel strike coating. Electrodeposition was performed by constant current electrolysis.

The performance as the cathode for alkaline water electrolysis was confirmed by LSV by use of saturated saturated calomel electrode (SCE) as reference electrode, Nickel electrode as counter electrode. Test solution was 30 wt % KOH aqueous solutions.

Log Exchange current density for hydrogen evolution reaction and hydrogen overvoltage obtained for thus prepared Fe-Ni-W electrode superior to those for Ni-P, Ni-W-S or Ni-W-P. The value is comparable to that for platinum electrode for acidic water electrolysis.
Anisotropic Electroless Deposition on Self-Assembled Biological Templates for Electronic Circuit Fabrication
Authors: Uprety Bibek , Harb John N.
Published: February 2020

Biological molecules like DNA can self-assemble into a variety of complex 2-D and 3-D architectures with very low energy consumption and without the need for expensive patterning tools. In addition, self-assembled DNA templates can also be designed to controllably place functional nanomaterials with molecular precision. These characteristics make DNA an attractive template for fabricating electronic circuits from biological molecules. However, electrically conductive structures are required for electronic applications. In this study, we demonstrate a metallization process that uses gold nanorod seeds followed by anisotropic electroless plating to provide improved morphology and greater control of the final metallized width of conducting metal lines. In addition, we demonstrate the controlled placement of gold nanorods on a DNA breadboard to make rectangular, square and T-shaped metallic structures that are then completed by anisotropic plating.

Nanowire formation begins with a seeding step where gold nanorods are attached to a DNA template to create a seed layer. Electroless gold deposition is then used to fill the gaps between seeds in order to create continuous, conductive nanowires. Importantly, growth during electroless deposition occurs preferentially in the length direction at a rate that is approximately four times the growth rate in the width direction, which enables fabrication of narrow, continuous wires. The electrical properties of nanowires with widths ranging from 13 nm to 29 nm were characterized, and resistivity values as low as 8.9 X 10-7Ω-m were measured.

For site-specific placement of nanorods to a DNA template, we modified the surface of the gold nanorods with single-stranded DNA. The rods were then attached to DNA templates via complementary base-pairing between the DNA on the nanorods and the attachment strands engineered into the DNA “breadboard” template. Gaps between the nanorods were filled controllably via anisotropic plating to make continuous metallic structures of different shapes. The combination of molecularly directed deposition and anisotropic metallization presented here represents important progress towards the creation of nanoelectronic devices from self-assembled biological templates. Continuing efforts seek to interface these thin DNA metallized structures with active elements to enable device fabrication through self-assembly.
Flexible Non-Enzymatic Glucose Sensor Obtained Via Wet Metallization Coupled with Inkjet Printing
Authors: Bernasconi Roberto , Molazemhosseini Alireza , Mangogna Alessandro , Magagnin Luca
Published: February 2020

Flexible sensors and electronic devices constitute one of the great frontiers of research in the third millennium. The advantages of these technologies are obvious: the possibility to wrap or fold the devices (with space saving benefits), the opportunity to manufacture wearable accessories and the weight reduction of the final product [1]. Many vital sectors of the modern manufacturing industry are interested by the general evolution towards flexible electronics: displays, solar cells, batteries and sensors.

In the case of biosensors in particular the development of flexible devices is particularly attractive due to their ability to adapt to human body, making possible the realization of wearable medical equipment. Example of biosensors include devices for the detection of glucose, organophosphates, proteins, antibiotics and many others. Their working principle may vary, but one of the most promising is the electrochemical one. Most of the electrochemical sensors are based on an enzyme mediated catalysis that produces or uses electrons. The resulting flux of current can be quantified and used for the sensing of the target specie.

These sensors, called enzymatic, present however some disadvantages. Firstly, the enzyme loses activity over time. Moreover, the enzyme is typically not completely stable when immobilized on a substrate. For these reasons, a primary goal of modern research on biosensing is the development of non-enzymatic sensors.

In the present work, a flexible non-enzymatic electrochemical glucose biosensor is presented. The functioning of the device is based on CuO, a common p-type semiconductor already used for the manufacturing of non-enzymatic glucose sensors [2, 3]. CuO nanoparticles are synthesized via a hydrothermal reaction and inkjet printed on a flexible substrate. Such flexible substrate is obtained by electroless plating with NiP a polymer sheet and by subsequently applying a platinum layer via electrolytic deposition. Sensitivity and selectivity of the obtained devices are finally tested with electrochemical techniques and their operative range is determined.

The obtained single use bendable sensors may result of great interest for the control of patients affected by diabetes mellitus, a pathology that constitute one of the primary health risks in the world.

[1] M. A. Alam, and S. Kumar; ed. B. Bhushan; “Flexible Electronics" chapter in Encyclopedia of Nanotechnology, Springer Netherlands, Dordrecht (2012) 860-865

[2] R. Ahmad, N. Tripathy, Y. B. Hahn, A. Umar, A. A. Ibrahim and S. H. Kim, Dalt. Trans. 44 (2015) 12488-12492

[3] R. Ahmad, M. Vaseem, N. Tripathy and Y. B. Hahn, Anal. Chem. 85 (2013) 10448-10454
High Performance, Dual-Scale Porous Carbon Electrodes for Vanadium Redox Flow Batteries
Authors: Zhou Xuelong , Zeng Yikai , Jiang Haoran , Ren Yuxun , Zhao Tianshou
Published: February 2020

Among the many types of redox flow batteries (RFBs), the vanadium redox flow battery (VRFB) has been regarded as one of the most viable chemistries for commercialization [1]. However, one of the most challenging issues that limits its commercialization process is the high capital cost, resulting from the low-performance power-pack. The porous carbon electrode design exerts a significant influence on the battery performance, primarily because it contributes to the system polarization through not only the ohmic polarization, but also through activation polarization and concentration polarization [2, 3]. The most commonly used materials for VRFB electrodes are carbon fiber-based materials (carbon felts/papers/clothes) for their high electronic conductivity, high hydraulic permeability, chemical and electrochemical inertness. However, issues associated with the use of these materials including low specific surface area and poor electrochemical activity limit the VRFB to be operated at a low current density (~50 mA cm-2) [4].

In this work, we present a simple and cost-effective method to form different types of dual-scale porous electrodes via KOH activation of the fibers of different carbon materials, including carbon felts/papers/clothes. As shown in Fig. 1, the large pores (~10 μm), formed between carbon fibers, serve as the macroscopic pathways for high electrolyte flow rates, while the small pores (~5 nm), formed on carbon fiber surfaces, act as active sites for rapid electrochemical reactions. Hence, the dual-scale porous electrode is expected to deliver high surface area without any sacrificing in electrolyte permeability. Our preliminary results showed that Brunauer-Emmett-Teller specific surface area of these carbon materials is increased by more than 10 times and the battery assembled with dual-scale carbon-paper/cloth electrodes can even operate at 400 mA cm-2 with energy efficiency over 80%. Moreover, the dual-scale carbon-felt electrode showed stable efficiencies during more than 1000 cycles. Further characterizations and optimizations of these dual-scale electrodes and comparisons between them will be disclosed at the meeting.

References:

[1] W. Wang, Q. Luo, B. Li, X. Wei, L. Li, Z. Yang, Advanced Functional Materials. 23 (2013) 970-986.

[2] A.Z. Weber, M.M. Mench, J.P. Meyers, P.N. Ross, J.T. Gostick, Q. Liu, J. Appl. Electrochem. 41 (2011) 1137-1164.

[3] M.L. Perry, A.Z. Weber, J. Electrochem. Soc. 163 (2016) A5064-A5067.

[4] B. Li, M. Gu, Z. Nie, Y. Shao, Q. Luo, X. Wei, X. Li, J. Xiao, C. Wang, V. Sprenkle, Nano letters. 13 (2013) 1330-1335.

Figure 1
Renewable Hydrogen at Scale: An Essential Piece of the Energy Puzzle
Authors: Ayers Katherine E , Danilovic Nemanja , Gellett Wayne L. , Capuano Chris
Published: February 2020

Increased penetration of intermittent renewable energy sources such as wind and solar is driving a need for improved energy storage technologies to manage the overall grid supply and demand, for short term fluctuations as well as long-term seasonal time variations. This challenge will require a combination of solutions, depending on geography, the mix of renewables, and other factors. At the same time, the need for a sustainable source of hydrogen has been widely recognized, not just as a potential transportation fuel, but to limit CO2 production and fossil fuel consumption from existing industrial processes such as ammonia generation. Leveraging renewable hydrogen as an energy storage solution has gained momentum through H2@Scale, an initiative to look at the synergies between intermittent renewable energy sources, industrial applications, transportation, and other grid management considerations. This talk will focus on the evolution of membrane-based water electrolysis as a renewable hydrogen pathway, and implications for industrial and energy applications.

Commercial proton exchange membrane (PEM)-based electrolysis has advanced to larger and larger scale over the last fifteen years, progressing from systems of 1 kg H2/day or less to several hundred kg/day. While leveraging the same basic manufacturing processes and technology, scale up has driven down the capital cost per kg of hydrogen by over 80%. PEM electrolysis also has tremendous potential for continuing cost reduction, leveraging system and manufacturing scaling laws as well as leveraging advancements in PEM fuel cell materials, manufacturing, and analysis tools. Order of magnitude improvements in some of the highest cost elements are easily achievable. The technology elements are known, but need to be refined and validated in a manufacturing environment, including modifications in materials and methods of fabrication. This talk will present a case study on successful implementation of cost reduced components for PEM electrolysis, opportunities for similar reduction in other components, and overall impact on cost and efficiency.
A New Enclosed Design for Vanadium Redox Flow Battery Cells
Authors: Al-yasiri Mohammed , Park Jonghyun
Published: February 2020

Abstract

Vanadium Redox Flow Batteries (VRFBs) represent one class of electrochemical energy storage devices, which are principally nominated for stationary applications. In this work, a new enclosed-type single-cell design of VRFB that includes serpentine flow channels is fabricated and tested experimentally. The introduced design includes desirable features such as safety, ease of assembly, and fewer components than traditional VRFB cells, meaning that it does not require gaskets, insulators, graphite plates, and end plates, making it a very cost-effective design. It also has more mechanical strength due to the replacement of the graphite flow field plate (brittle and porous) with a hard and impermeable thermostatic material, PVC (Poly Vinyl Chloride) sheet, which ensures a longer lifespan, especially in harsh environments exposed to shocks and vibrations. Many tests have been conducted in order to compare this new design with the traditional one, including cycling, polarization over a range of currents along with a range of flow rates, and electrochemical impedance spectroscopy (EIS) for internal resistance analysis. The results show that the new design has very stable cycling performance with better columbic and energy efficiencies compared to the traditional one, also it reflects the normal behavior of single cycles at different loading conditions, and it can provide more output current through the polarization test and, subsequently, higher output power. Finally, an economic analysis was conducted that compares the costs associated with the two designs and it is found that the new one is cheaper, less weight, and easy assembly.
Validated Analytical Model to Project and Price New Flow Batteries for the Grid
Authors: Ma Rose Xiaoya , Yan Yushan
Published: February 2020

A more renewable electrical grid is demanded by exacerbating fossil fuel depletion and environmental repercussions. Among renewables, wind and solar photovoltaics are expected to see the fastest growth1,2, notwithstanding their inherently variable supply. To sustain the pace of renewable development, then, calls for electrical energy storage (EES) technologies, which would ease integration and allow higher capacity. However, given the anticipation that electricity costs remain below 14 cents per kilowatt-hour for decades to come2, EES devices must above all be cost-effective. 

Redox flow batteries (RFBs) are a standout EES candidate3. Unlike in a traditional solid-state battery, in an RFB, electrolytes are stored external to the electrode; as such, RFBs enjoy good efficiency, durability, and safety. More notably, RFBs see independently designable power and energy capacity. Further flexibility is possible in both redox chemistries and cell/stack design.

At the same time, the breadth of possible innovations for RFBs tends to confound the question of cost-effectiveness. Indeed, to evaluate a new RFB for the grid requires either risky scale-up ventures (for experimental studies) or a comprehensive, generalizable model (for theoretical studies). We present the latter, with characterization of: activation overpotential in reaction networks, ohmic overpotential in concentrated electrolytes, concentration overpotential in different membrane-electrode configurations; as well as stack losses. Requisite characteristic parameters can be validated by independent experimental measurements. We also validate our overall model for a range of chemistries, layouts, and scales (Figure 1). In doing so, we demonstrate nearly instantaneous screening of new designs, an indispensable approach to both inform and direct future RFB development.

References:

International Energy Agency. World Energy Outlook 2016 (WEO-2016). 2016.

U.S. Energy Administration. Annual Energy Outlook 2016 (AEO-2016). 2016.

Yang Z, Zhang J, Kintner-Meyer MCW, Lu X, Choi D, Lemmon JP, Liu J. Chem. Rev. 2011; 111:3577.

You D, Zhang H, Chen J. Electrochim. Acta
2009; 54:6827.

Zhao P, Zhang HM, Zhou HT, Yi BL. Electrochimica Acta
2005; 51:1091.

Gu S, Gong K, Yan EZ, Yan YS. Energy Environ. Sci.
2014; 7:2986.

Gong K, Ma RX, Conforti KM, Kuttler KJ, Grunewald JB, Yeager KL, Bazant MZ, Gu S, Yan YS. Energy Environ. Sci.
2014; 7:2986.

Figure 1
Low Energy Phosphorus Plasma Implantation for Isolation of MoS2 Devices
Authors: Haynes Katherine , Murray Ryan , Zhao Xueying , Chiappe Daniele , Sutar Surajit , Radu Iuliana , Hatem Christopher , Perry Scott , Jones Kevin Scott
Published: February 2020

MoS2 is a promising two-dimensional material that is being considered as a replacement for Si in sub-5 nm device technologies. Integration could include the growth or transfer of large areas of MoS2 films onto Si wafers. Subsequent isolation of devices fabricated on MoS2 films is an open research area that has received little attention. Although reactive ion etching or chemical etching can be used to create isolated channels, these techniques are problematic due to the weak van der Waals interaction between the two-dimensional films and their substrates. Subsequent wet processing during lithography can cause delamination from the substrate, resulting in mechanical damage to the films or even displacement of the channels. An alternative to physical isolation of MoS2 was the focus of this study. It is known that, in many semiconductors, radiation damage can be used for isolation. In this study, large-area 3-5 layer MoS2 films were grown on sapphire and subsequently transferred onto SiO2/Si wafers. The MoS2 was then exposed to low energy phosphorus plasma implantation at biases of 100, 200, and 300 V and a dose of 1 x 1014 cm-2. Electrical measurements using patterned Ni/Au contacts show that after implantation, independent of bias, there is a 105 increase in resistivity and a similar increase in specific contact resistivity of the MoS2. TEM shows that the film is still crystalline and there is no measurable etching of the films after implantation, suggesting that the increase in resistivity is likely the result of radiation damage in the MoS2. The thermal stability of the increase in electrical resistivity was assessed by a series of 15 minute anneals beginning at 325°C in a sulfur overpressure and progressing up to 525°C under an Al2O3 ALD cap. The resistivity increase remained unchanged after annealing, suggesting that this is a stable alternative to physical isolation in MoS2 devices.
Atomic Engineering of Chalcogenide Layer in Transition Metal Chalcogenides
Authors: Yang Chih-Wen , Lu Ang-Yu , Li Lain-Jong
Published: February 2020

Atomically thin transition metal chalcogenides (TMDs), members of two-dimensional (2D) material family, have received great attention due to their novel optoelectronic and electronic properties. CVD technique have been well developed to synthesize monolayer TMDs, such as MoS2, WS2, WSe2, and MoSe2 where transition metals are sandwiched by the same chalcogenide layers1. Band gas of those intrinsic materials can be further manipulated by precisely compositional control of TMD alloy structure2. For example, band gap of MoSxSe2-x sat in between MoS2 and MoSe2. Although great effort had paid in fabricating such complex 2D structures had been fabricated, compositional control of TMD along the vertical direction remains challenging. Such asymmetrical composition distribution could result in additional polarity along the vertical direction and extend its application to spintronics3. Here, we develop a method that can precisely manipulate arrangement of chalcogenide atoms (S and Se) along the vertical direction of TMD by applying plasma thinning along with selenization (or sulfurization). This new strategy is not only to control the composition of upmost chalcogenide layer but also able to fabricate MoSSe Janus structure. In this Janus structure, the transition metals are sandwiched by selenium at upmost and sulfur at bottom. Raman spectra is applied to track and investigate the mechanism. Furthermore, this approach can be generalized to other 2D materials. Janus WSSe is also successfully achieved by applying similar plasma treatment and corresponding chalcogenization.

References:

1. Nat. Nanotechnol.
2012, 7, 699.

2. Adv. Mater. 2014, 26, 2648.

3. EPL, 2013, 102, 57001.
Substituent Effects of Organosilicon-Based Lithium-Ion Battery Electrolytes for Increased Thermal Stability
Authors: Guillot Sarah Lucienne , Peña Hueso Adrián , Usrey Monica Lee , Hamers Robert J
Published: February 2020

Electrolyte stability is one of the foremost challenges in improving the lifetime and operation of lithium-ion batteries. Despite their desirable high conductivity and solvation properties, conventional carbonate electrolytes have low flash points, low thermal stability, and limited electrochemical windows which give rise to significant safety and performance issues. Electrolyte degradation leads to the formation of problematic gaseous products and decomposition species that can trap lithium and increase cell impedance, leading to capacity fade. Silatronix, Inc, with the University of Wisconsin-Madison, has developed a novel class of electrolytes based on organosilicon solvents with decreased flammability, which have displayed enhanced electrochemical stability and reduced gassing. To understand the degradation mechanisms and structural components behind these improved properties, we report thermal, electrochemical, and hydrolytic stability studies of 4 organosilicon electrolytes with varying molecular substituents, and compare these organosilicons with conventional carbonate electrolytes. We identify and quantify thermal hydrolysis and electrochemical degradation electrolyte products via multinuclear NMR. We report insights into the manner by which different substituents affect electrolyte decomposition, and identify several mechanisms in organosilicon electrolytes that seem to inhibit degradation. Elucidation of the mechanisms of degradation for organosilicon electrolytes will help enable the design of future electrolytes with superior performance.
Nanoscale Xpeem Spectroscopy Reveals the Origin and Nature of the Lto Electrode Surface Reactivity
Authors: Leanza Daniela
Published: February 2020

A stable electrode/electrolyte interface is an essential requirement to ensuring safe operation and long-life span of Li-ion batteries. The challenge of assessing such stability relates to the difficulty of determining the exact thermodynamic stability window of the electrolytes. Indeed, the strong mismatch between the theoretical and experimental values and their dependence on the investigated electrode remains a major hurdle in the field. Surprisingly, the presence onf a surface layer, as a result of electrolyte decomposition, has been reported on Li4Ti5O12 (LTO) electrodes operating at a voltage plateau where the electrolyte components are expected to remain stable. Despite the considerable work aimed at elucidating the origin, thickness and homogeneities of such surface layer, there is still a lack of knowledge on the reaction mechanism behind its formation. Here we propose the use of a spatially-resolved technique, the X-Ray PhotoEmission Electron Microscopy (XPEEM), to gain information on single particles of the composite electrode at different stages of cycling. By combining nanoscale microscopy capabilities with local spectroscopic features within the first 3-4 nm from the surface, we are able to gain unique information on the different particles of the LTO surface. The high lateral resolution achieved with the XPEEM on a LTO electrode is attested in Figure 1.A showing the elemental distribution of the active material (blue), carbon (red) and binder (green) particles. The local XAS spectra acquired at the C K-edges on carbon (Figure 1.B) and LTO (Figure 1.C) areas provide a straightforward signature of their different reactivity upon cycling. Indeed, we demonstrate the presence of a surface layer solely on top of the LTO particles and only on lithiated samples. Thus, we provide an innovative solution to study the complex electrode/electrolyte interaction and propose a mechanism that explains the surface layer formation and the distribution across the LTO electrode, opening the way to achieving an optimized electrode and electrolyte engineering.

Figure 1
Highly Proton Conductive sPPEK /SSi-GO Composite Membranes for Proton Exchange Membranes Fuel Cells
Authors: Zhu Xiuling , Huang Jianyu , Jin Cuihong , Zhang Shuai , Li Shuai , Jiang Ben , Sun Fang
Published: February 2020

Our work has focused on the development of polymer electrolyte materials, and the membranes for the potential application of AEMFC, PEMFC, redox flow battery, and other electrochemical energy fields. Alkaline anion exchange membrane fuel cells (AEMFCs) attract much attension because they could utilize non-noble metals as catalysts, such as Ni, Ag peroxide. Furthur, SSi-GO based composite membranes was prepared with SPPEK aimed at the establishment of the ionic transport channel. The proton conductivity of 10% content composite membranes reached 0.094 S/cm at 30℃, and 0.220 S/cm at 80℃ much higher than Nafion 117, which indicated the potential application of SPPEK-SSi-GO composite membranes for PEMFC.
Solid-State Electrolytes in the Class of Complex Hydrides with Lithium Ion Conductivities Near Liquid Electrolytes
Authors: Kühnel Ruben-Simon , Yan Yigang , Duchêne Léo , Roedern Elsa , Cuervo Reyes Eduardo , Remhof Arndt , Battaglia Corsin
Published: February 2020

All-solid-state lithium-ion batteries employing solid-state electrolytes promise higher operational safety, enhanced temperature stability, potentially higher cell voltages, and consequently higher energy density compared to traditional batteries with liquid electrolytes based on flammable organic solvents. So far, only a few oxide- and thiophosphate-based solid-state electrolytes exhibit lithium ion conductivities near room temperature comparable to liquid organic electrolytes. However, none of these electrolytes has enabled the fabrication of a competitive all-solid-state battery yet. Here we report the discovery of a superionic phase near room temperature in the class of lithium amide-borohydrides, enabling ionic conductivities of 8 mS/cm near room temperature, comparable to values of common organic liquid electrolytes. The transition into the superionic phase is demonstrated to be triggered by melting of a fully occupied lithium sublattice into a symmetry-equivalent interpenetrating dual sublattice consisting of lithium vacancy sites. We further demonstrate excellent rate performance up to 5C and stable cycling over 400 cycles at 1C of our solid-state electrolytes in half-cell battery configuration representing an important step towards a viable solid-state battery technology.
Defect Chemistry and Electrical Properties of Garnet-Type Li7La3Zr2O12
Authors: Zhan Xiaowen , Shirpour Mona
Published: February 2020

Developing batteries with high energy density, safe operation, low cost, and long life is vital for successful implementation of lithium-ion batteries in the automotive industry. The replacement of the organic liquid electrolytes with nonflammable solid electrolytes in lithium-ion batteries improves safety, offer higher volumetric and gravimetric energy densities, and potentially lower the cost of the battery by increasing the battery life, decreasing the dead space in the battery pack, and simplifying the packaging.

Garnet-type cubic Li7La3Zr2O12 (c-LLZO) has emerged as a promising candidate for solid electrolytes due to its high ionic conductivity (up to ~1 mS/cm at room temperature), good chemical stability against lithium metal, and wide electrochemical stability window. Defect chemistry of this class of materials, yet less studied, is critical to the understandings of the ionic nature of conductivity and the electrode-electrolyte interfacial resistance. In this study we will discuss the defect chemistry of c-LLZO, i.e., the formation of ionic defects and defect pairs as well as their impact on the electrical properties of c-LLZO. The contribution of grain boundaries to the electrical conductivity of polycrystalline samples will also be presented.
Phase Formation during Solid State Synthesis of Lithium Ion Conducting Garnet from Nitrate and Carbonate Precursors
Authors: Schmidt Robert , Sacci Robert L , Kirkham Melanie J. , Dudney Nancy J , Huq Ashfia
Published: February 2020

In a previous study, the solid state synthesis of Li7La3Zr2O12 (LLZO) has been explored by neutron diffraction (ND) showing numerous intermediate phases present during heating, however no consideration was made for alternative solid state synthesis precursor materials. With alternative precursor materials, the intermediate phases that are formed may be changed, and the temperature required for synthesis may be reduced. Furthermore, a change in precursor materials can reduce or eliminate potential undesirable phases or contaminants in the final product. In this study, the synthesis of LLZO is explored by both neutron diffraction and mass spectroscopy of the flow gas, comparing solid state synthesis with either Li2CO3 or LiNO3 as the lithium precursor. Intermediate phases are examined as a function of temperature from RT to 800°C. It was demonstrated that the temperature for solid state synthesis of LLZO may be reduced by changing the lithium precursor choice from Li2CO3 to LiNO3, and the change in precursor results in a change of the intermediate phases observed.

The work was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering Division.
Atomistic Understanding of the Difference in Ionic Conduction Between the Alpha and Alpha' Phases of Nasicon LiZr2(PO4)3
Authors: Vander Marcken Gil , Miglio Anna , Dollé Mickael , Hautier Geoffroy , Rignanese Gian-Marco
Published: February 2020

Lithium-ion batteries presents safety hazards due to their electrolyte. The

electrolyte is typically an organic flammable liquid, and their proximity to

an oxidizing agent can lead to thermal runaway and explosion in extreme

cases.

To overcome those inconveniences, the use of solid state electrolyte has been

suggested. They are inflammable and exhibit a higher stability. However,

their low ionic conductivity (less than 10^-4 S cm-1) hindered so far their

use in commercial batteries.

LiZr2(PO4)3 in the NASICON structure is a promising solid state electrolyte

with attractive Li-ion conductivity of 10^-5 S cm-1 and stability. This

compound undergoes a reversible phase transition from a triclinic structure

(called alpha') to a rhomboedral one (alpha phase) at 330K. It is

experimentally known that the conductivity of the alpha' phase is three

orders of magnitude lower than the estimated conductivity of the rhomboedral

phase at room temperature.

It is however not clear yet to what atomistic mechanism could explain this

large difference between two very close structures: the alpha and alpha’

phases. In this work, we have performed an ab initio study of Li diffusion in

both alpha and alpha’ phases using ab initio molecular dynamics and nudge

elastic band. Based on this computational insight, we identify the

differences and similarity between the two phases and shine light on the

reason for the higher performance of the alpha phase.
Design of Novel Electrolytes to Protect Lithium Metal Anodes in Li-S Batteries
Authors: Adams Brian , Cao Ruiguo , Chen Junzheng , Zhang Ji-Guang
Published: February 2020

With a theoretical specific energy of 2500 W h kg-1 and energy density of 2800 W h L-1, the Li-S battery system is believed to provide the step-up in energy density necessary for lithium-based battery technologies to expand from portable electronics to transportation and grid-storage applications.1 However, the growth of dendrites during repeated Li plating/stripping and the low coulombic efficiency (CE) of these processes have limited application of rechargeable Li metal batteries.2 For example, a 300% excess amount of lithium often used in these batteries would directly result in halving the theoretical specific energy of the Li/S cells.

In this presentation, the design of new electrolyte systems which enable high CE of lithium metal plating/stripping and high stability in the sulfur environment will be discussed. Tailoring of electrolyte properties for the lithium negative electrode has proven to be a successful strategy for improving the capacity retention and cycle life of Li-S full cells. This also enables lower electrolyte/sulfur mass ratios to be used and a lower excess of lithium metal; ultimately increasing the energy density of the system.

A new class of electrolytes based on a high concentration of selected lithium salts in pure diethylene glycol dimethyl ether (diglyme) solvent provides a CE for lithium plating/stripping of greater than 99% for over 200 cycles and greater than 95% for over 500 cycles (Figure 1). In contrast, lithium metal cycles for less than 40 cycles at high CE in the standard 1 M LiTFSI + 2wt% LiNO3 in DOL:DME electrolyte.

To realize the benefits of sulfur cathodes over intercalation cathodes currently using in Li-ion cells, high loading (high capacity) cathodes need to be used. In Figure 2a, a Cu||Li cell is cycled with the new diglyme-based electrolyte to a capacity of 6 mAh/cm2 at a current density of 0.6 mA/cm2 (C/10). Even at this high capacity, lithium is cycling with >99% CE. Lithium symmetrical cells were also cycled at a current density of 0.5 mA/cm2 to 5 mAh/cm2 (Figure 2b). In this case, the increase in polarization was used a metric to determine the practical cycle life of Li metal in the different electrolytes. No polarization is observed for the diglyme-based electrolyte after 2200 hours in the Li||Li cell. 

The inexpensive sulfur cathode paired with a low excess of lithium metal and the low-cost salt/solvent system may accelerate the applications of high energy density Li-S batteries in both electrical vehicles and large-scale grid energy storage markets.

References

1. A. Manthiram, Y. Fu, S.-H. Chung, C. Zu, Y.-S. Su, Chem. Rev.
2014, 114, 11751-11787.

2. W. Li, H. Yao, K. Yan, G. Zheng, Z. Liang, Y.-M. Chiang, Y. Cui, Nature Comm.
2015, 6, 7436.

Figure 1
Characterizing the Effects of the Alkyl Chain Length of Linear Organic Carbonates on Lithium Ion Electrolyte Structure and Dynamics: A Solvent Perspective
Authors: Fulfer Kristen D'Ann , Kuroda Daniel G
Published: February 2020

In the past two decades, lithium ion batteries have become the workhorse of the portable energy storage industry. Despite the progress which has been made in regards to improving lithium ion batteries, there is strong need to improve the safety and efficiency of this technology. So far, studies have focused on improving the electrodes or on optimizing the electrolyte composition. However, very few studies have focused on characterizing the structure and dynamics of the electrolytes at the molecular level. In this work, we have utilized both steady-state and time-dependent infrared spectroscopies to characterize the structure and dynamics of lithium ion electrolytes composed of linear organic carbonates with different structures. Specifically, we present the effects of increasing the alkyl chain length of the linear organic carbonate on the structure and dynamics of lithium ion solvation shell. Surprisingly, the lithium ion shows a tetrahedral solvation structure in the various linear carbonates in which little effect is observed from increasing alkyl chain length. However, the time-resolved studies reveal a clear slowdown of the solvation shell motions when the alkyl chain length of the linear organic carbonate is increased. Thus, our studies reveal that the molecular structure of the carbonate solvent has far reaching consequences on the structure and dynamics of the electrolyte formed and direct implication on the macroscopic properties of the electrolyte.
Improving Performance and Cyclability of Printed Flexible Zinc-Air Batteries Using Carbopol Gel Electrolyte
Authors: Chaduang Sunida , Lao-atiman Woranunt , Kheawhom Soorathep
Published: February 2020

Rechargeable batteries are critical as power sources used in various applications such as electrical vehicles, grid-scale storages and portable electronics. Zinc-air batteries are attractive because these batteries use raw materials which are relatively low cost, have low toxicity and are environmentally friendly but exhibit high specific energy density. Moreover, zinc is relatively safe and stable. However, under repeated charging and recharging, zinc anodes undergo a dendrite formation problem. Zinc anode dissolves into electrolyte during discharge and deposited back during recharge. During recharge, dendritic zinc is formed easily and can cause internal short circuits resulting in shortening cycle life of the batteries.

Gel polymer electrolyte have been extensively studied for their ability to improve performance of the batteries in various ways. Specifically, gel polymer electrolytes have shown promise as candidates to suppress zinc dendrite growth. However, the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials.

Thus, this work aims at investigating and discussing the role of carbopol gel electrolyte in rechargeable flexible printed zinc-air batteries. The rechargeable zinc-air batteries are fabricated using an inexpensive screen-printing technique. The anode and cathode current collectors are printed using commercial nanosilver conductive ink on a polyethylene terephthalate (PET) substrate and polytetrafluoroethylene (PTFE) laminated with polypropylene (PP) membrane, respectively. Nylon membrane is used as the separator. Air cathodes are fabricated using blended graphite powder with MnO2 and sodium silicate. Anode electrodes are fabricated using formulations consisting of zinc, graphite powder and sodium silicate.

Carbopol gel electrolyte is investigated in order to elucidate the nature of the different microstructures of the gel in relation to the concentration of carbopol. In addition, the effects of the concentration of carbopol (0.1–5 wt.%) on ionic conductivity is investigated. Electrochemical impedance spectroscopy (EIS) is employed to investigate the electrochemical properties of the gel electrolyte. Moreover, the effects of the concentration of carbopol on polarization curve, discharge-recharge profile of the batteries at various current densities are analyzed. The morphology of the anodes and its electrochemical parameters are studied as a function of discharge-recharge cycle. The results showed that carbopol gel electrolyte significantly inhibit the formation of dendrites, and significantly increasing the number of achievable cycles.

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Acid-Stable, Low-Noble-Metal Content Oxygen Evolution Electrocatalysts Via Rapid Plasma Synthesis
Authors: Kumari Sudesh , Robinson Chris , Ajayi Babajide , Sunkara Mahendra Kumar , Spurgeon Joshua M
Published: February 2020

One outstanding research challenge in water-splitting electrocatalysis is that few known materials have both high catalytic activity and extended stability for the oxygen evolution reaction in acidic electrolytes, and these have primarily been limited to noble metal oxides. A rapid and scalable novel plasma synthesis technique has been employed to fabricate mixed metal oxide compositions of homogeneously phase-pure catalysts with an aim toward the development of acid-stable OER catalysts of low noble metal content. In particular, a composition of W0.9Ir0.1Ox has been characterized and shows high activity and stability at pH 0 following a standardized benchmarking protocol. A high-throughput plasma reactor nanoparticle printer has been developed to enable the rapid search for acid-stable OER catalysts with minimal to no platinum-group-metal elements. Such materials could improve the sustainability and economic competitiveness of proton exchange membrane electrolyzers.
Doped TiO2 supported-Catalysts for Oxygen Evolution Reaction in Polymer Electrolyte Membrane Electrolytic Cell
Authors: Kim Eom-Ji , Kim Minjoong , Cho EunAe
Published: February 2020

Polymer electrolyte membrane electrolytic cells (PEMECs) is one of appropriate energy storage systems connected with renewable energy due to high drive current and endurance under road fluctuation. In water electrolysis, oxygen evolution reaction (OER) occurs under acidic and high potential. So, the large amount of precious metal catalyst is needed for performance and stability. Introduction of supporting materials could reduce the amount of precious metal catalyst without performance degradation. Titanium oxide (TiO2) is one of few materials which shows good stability under acidic and high potential conditions. Also low electronic conductivity of TiO2 (~10-6 S/cm) can overcome with introduction of appropriate doping element into TiO2.

In this work, various metal elements were doped into TiO2 supporting materials. M-doped TiO2 were prepared by electrospinning method. Figure 1 (a) is a SEM image of prepared nanofiber TiO2. M-doped TiO2 were characterized to study physical and chemical properties. Then, iridium catalysts on M-doped TiO2 support (Ir/M-doped TiO2) were synthesized by polyol method and were electrochemically evaluated. OER activity of prepared catalysts was measured by linear sweep voltammetry in oxygen-saturated 0.5 M H2SO4, respectively. As shown in fig. 1 (b), polarization curves for each catalysts were changed as variation of doping elements. Ir/M-doped TiO2 shows higher OER activity than iridium black. From these results, it was obtained that introduction of dopant into TiO2 change the characteristics of TiO2 and this change contribute to improvement OER activity. Ir/M-doped TiO2could be suggested OER catalyst to reduce the amount of precious metal catalyst without performance degradation.

Fig 1. (a) SEM images of electrospun TiO2 nanofiber, (b) Polarization curves of prepared catalysts and commercial Ir black measured in O2-saturated 0.5 M H2SO4 solution at room temperature with rotation speed of 1600 rpm and scan rate of 2 mV/sec

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A Molecular Ni-Complex Containing Tetrahedral Nickel Selenide Core As Highly Efficient Electrocatalyst for Water Oxidation
Authors: Masud Jahangir , Nath Manashi , Kyritsis Panayotis
Published: February 2020

The accelerated depletion of fossil fuels has intensified research efforts towards designing materials capable for storage of electricity captured from sustainable but intermittent energy sources (e.g., wind and sunlight) in the form of chemical bonds (as H2 fuel) through water splitting.1 The water-splitting reaction can be divided into two half reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), among which the OER reaction is energetically more challenging and forms a major roadblock.2 Many catalysts have been explored to expedite the reaction rate and lower the overpotential toward HER and OER.3 Transition metal chalcogenides (Mx
E
y, M= Fe, Ni, Co; E = S, Se) have been recently identified as cost-effective, and efficient electrocatalysts for OER and HER energy conversion processes.3-5

In this meeting, we will report on the electrocatalytic activity of a seleno-based metal coordination complex, [Ni{(SeP
i
Pr2)2N}2] (1), which shows enhanced catalytic activity for both OER and HER in alkaline medium. The onset potential for O2 evolution, as well as the overpotential at 10 mA cm-2, was the lowest at 1.4 V and 200 mV, respectively (Fig. 1). The onset potential for H2 evolution was also very low as compared to that of other non-Pt based HER electrocatalysts. A full water electrolysis could be achieved by coating both the cathode and the anode by this bifunctional catalyst, achieving a current density of 10 mA cm-2at 1.8 V. This catalyst significantly enhances gravimetric current density (111.02 A/g) for OER process, thereby reducing the amount of active material required, without compromising the overal performance of the catalytic system.

References:

1. N. S. Lewis, D. G. Nocera, Proc. Natl. Acad. Sci. U. S. A., 2006, 103, 15729–15735.

2. J. O. Bockris, A. K. N. Reddy, Modern Electrochemistry, Vol 1: Ionics, (Ed.: J. O. Bockris), Springer, USA, 1998.

3. J. Masud, P. C. Ioannou, N. Levesanos, P. Kyritsis, M. Nath. ChemSusChem

2016, 22, 3128

4. A. T. Swesi, J. Masud, M. Nath, Energy Environ. Sci.
2016, 9, 1771

5. J. Masud, A. T. Swesi, W. P. R. Liyanage, M. Nath, ACS Appl.Mater. Interfaces
2016, 8, 17292.

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