bluuebunny/crossref_metadata_2025_split huggingface dataset:
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
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.
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
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.

Figure 1
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

Figure 1
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.

Figure 1
(Invited) Perovskite Oxide As High Performance Bifunctional Catalyst in Alkaline Solution
Authors: Yan Litao , Luo Hongmei 
Published: February 2020

The global energy crisis coupling with the consumption of fossil fuels and the associated environmental issues, has stimulated extensive interest in searching for clean, efficient and sustainable energy storage and conversion systems. Producing oxygen through an OER process can be promising when effective catalysis of water oxidation into oxygen molecules could be achieved. Therefore, developing an efficient OER electrocatalyst is vital to the new generation of electrochemical storage and conversion devices such as electrolyzer, hydrogen production from water and metal-air batteries. However, there are still several challenges that have to be solved for the electrochemical water oxidation process to become economically attractive One of them is associated with the high overpotential and thereby energy losses at the electrode, where OER is taken place with four electron transfer, according to the following overall reaction:
2H2O (l) + 4 × 1.23 eV → O2 + 4H+ + 4e- (1)
Oxygen reduction reaction (ORR), reversible reaction of OER, also play an important role in electrochemical energy storage devices including fuel cell and metal air battery. Advanced ABO3 perovskite oxides with improved catalytic properties have been extensively developed and modified as bifunctional catalyst because of their high versatility in composition, crystalline and electronic structure. In this paper, (La0.8Sr0.2)1-xMn1-xIrxO3 (x=0, 0.05 and 0.1) nanoparticles with particle size of 20-50 nm were succesfully developed as the superior bifuctional catalyst in alkaline solution. The onset potential for ORR is around 0.92V, which is only 50 mv negative shift for state of art Pt/C catalyst while the onset potential for OER is around 1.55 V, which is comparabel with a state of art IrO2 catalyst.
Exploring Graphitic Carbon Nitride Based Nano-Heterogeneous Photocatalysts for Elimination of Wide Range of Contaminants and Water Splitting
Authors: Pawar Rajendra Charandeo , Kang Suhee , Lee Caroline Sunyong 
Published: February 2020

Presently, contamination of waster with harmful and waste materials, leading to significant adverse effect on the environment and wildlife. Direct disposal of nonbiodegradable and undesirable chemical compounds into water makes it unsuitable for drinking and for other purposes. Hence, elimination of contaminants from wastewater has become an important issue, because of the adverse effects on human health and environment. Conventionally, various techniques including advanced oxidation, coagulation, adsorption, reverse osmosis, and ion exchange have been used to remove these hazardous pollutants from polluted water. Of these, photocatalysis purification based on heterostructures are one of the most prominent technologies in the direct use of solar energy for the degradation of wide range contaminants and production of H2; these are potentially the best promising green technologies that replace conventional energy resources. In order to achieve the desired efficiency, the photocatalysts should have an excellent light absorbance, rapid charge separation, and a high chemical stability. A great deal of effort has been devoted to enhancing the efficiency of the photocatalytic process and extending the light adsorption range of photocatalysts; these include formation of semiconductor nanoheterostructures, co-deposition of noble metals, and coupling with other technology. Among the various approaches, formation of nano-heterojunctions is a promising approach; it can induce band bending at the interface of junction resulting in a built-in field, which can drive the photogenerated electrons and holes to move in opposite directions.
In our laboratory, we fabricated and investigated different nano-heterogeneous photocatalysts based on graphitic carbon nitride (g-C3N4) and its hybrids with aligned ZnO/TiO2 nanorods, ZnTiO3 nanofibers, Au nanoparticles and CNTs, and graphene nanosheets via solvothermal methods. The fabricated have been tested to degrade organic pollutants such as methylene blue, and rhodamine B have degraded under visible irradiation. In addition, we measured H2 evolution from water splitting under visible irradiation. The photocatalytic activities of nano-heterogeneous photocatalysts was seen to be better over the pristine structure. Improved performance was aroused from broadened the optical window, short diffusion distance for excellent charge transport, and increase contact area with supporting electrodes for rapid interfacial charge separation and transportation. Therefore, the present ternary graphene aerogel based nano-heterogeneous photocatalysts could be applicable in hydrogen production and water purification technology.