bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sulfide-Based Solid Electrolytes By Solution Processing
Authors: Lee Byoung-Sun , Xing Xing , Liu Haodong , Liu Ping 
Published: February 2020

Solid electrolytes (SE) have been considered as alternative components to organic liquid electrolytes in lithium batteries (LIB). They promise safety enhancement by preventing the safety risks (e.g., leakage and ignition) [1]. In addition, the possibility of replacing graphite anode with lithium can lead to higher energy densities. Among various SE types, Li2S-P2S5 based sulfide SEs consisting of PSx polyhedral anions have been extensively explored due to its superionic conductive performances [2]. Previously, the SE was fabricated as pellets from Li2S-P2S5 powders via sintering or cold-pressing to reduce the grain boundary resistance. However, the processing costs of the high-energy ball milling and/or sintering at high temperature are considerable. In the meantime, the SE pellets are very thick (> 200 μm) due to the need to maintain mechanical integrity during processing and handling, resulting in cell energy density reduction, and the SE pellet brittleness prevents efficient device integration. Therefore, a desirable SE synthesis process should be designed to meet the following requirements: 1) low processing cost, 2) easy device integration, and 3) high energy density. In this work, we describe a Li2Sy-P2S5 solution coating process for the SE synthesis on the basis of aforementioned three requirements. Morphologies, compositions, crystal structures, and microstructures of the synthesized SE layers (Figure 1) were thoroughly examined using SEM, Raman spectroscopy, XRD, and XPS, and electrochemical performances were assessed using electrochemical impedance spectroscopy (EIS) and lithium ion battery cycling performance. We will describe how the fine tuning of solution composition and reaction condition can offer solid electrolyte layers inherently amenable to device integration.
[1] Teragawa, S. et al., J. Mater. Chem. A 2, 5095 (2014)
[2] Ohara, K. et al., Sci. Rep. 6, 21302 (2016)
Figure 1. Solution process based solid electrolyte (SE) layers formed on a metal electrode: a) photograph, and b) cross-sectional SEM image, and EDX images of c) phosphorus and d) sulfur in cross-section shown in b).

Figure 1
(Invited) Megawatt PEM Electrolyzers: from Laboratory to Market, a Road Map
Authors: Hamdan Monjid 
Published: February 2020

Proton-exchange membrane (PEM)-based electrolysis is at the leading edge of a global energy system transformation. The energy vision of the future incorporates abundant renewable energy which is transformed into hydrogen for use in applications such as mobile refueling, power to gas, and grid-level energy storage. To meet these new market megatrends, PEM-based electrolyzer manufacturers are scaling-up their electrolyzer stack and system sizes with increased power capabilities (Figure 1).
This talk will focus on recent advancements in PEM-based stack technology, validation of subscale stacks and systems, and the eventual scale-up to Megawatt-scale hydrogen production; providing insight into PEM-based electrolyzer stack product development and scale-up strategies.
Giner, Inc. is a leading developer of PEM technologies and has extensive experience in the design and development of PEM-based electrolyzers, fuel cells and related electrochemical devices. Giner has continued the development of PEM-based electrolysis in the U.S., making significant advancements in stack efficiency, differential pressure operation, cost reduction, and scale-up. Our technology ranges from highly-reliable sub-scale electrolyzer stacks operating at a differential pressure of 5,000 psig to low-cost Megawatt electrolyzer stacks and systems operating at pressures of up to 600 psig for commercial applications.
The presentation will describe the efforts and requirements involved in testing, development, validation, and cost reduction, and will identify several areas of interest that have been implemented to further advanced PEM-based stack technology, including the development of innovative stack designs capable of high current density, and the scale-up of the electrolyzer stack to large active areas for Megawatt-scale hydrogen production.

Acknowledgements: The Author gratefully acknowledges financial support from the Department of Energy for the work described in this presentation.

Figure 1
(Invited) Electrochemical Atomic Layer Deposition of Ultrathin Electrocatalytic Films
Authors: Moffat Thomas P. , Ahn Sang Hyun , Liu Yihua , Bertocci Ugo , Gokcen Dincer , Ritzert Nicole L. , Wang Rongyue , Hangarter Carlos 
Published: February 2020

Development of a sustainable hydrogen economy based on water electrolysis and fuel cells is constrained by the performance, longevity and high cost of Pt group electrocatalysts. Important strategies for improving catalytic reactivity include alloying, forming bimetallic or alloyed surfaces, and engineering substrate–catalyst interactions. At the same time, significant effort is underway to minimize the loading of Pt group metals by examining new synthesis methods and electrode geometries. Of particular interest is atomic layer deposition (ALD) for growing ultrathin films that maximize utilization of rare, expensive metals and facilitate the exploration of bimetallic effects in electrocatalysis.
Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. The mechanism of self-terminated deposition reactions will be discussed and the utility of these films as bimetallic electrocatalysts will be demonstrated. For example, monolayer equivalent Pt and Ir films were found to match or exceed the best known specific HER/HOR activity for bulk polycrystalline Pt or Ir electrodes and thereby offer the promise of increasing the scalability of these important precious metals in energy conversion devices.
(Invited) In-Situ investigation of Triple-Phase Boundary Electrochemical Reactions in PEM Electrolyzer Cells
Authors: Zhang Feng-Yuan 
Published: February 2020

In-situ

Investigation of Triple-phase Boundary Electrochemical Reactions in PEM Electrolyzer Cells

Jingke Mo, Zhenye Kang, Gaoqiang Yang, Derrick Talley, and Feng-Yuan Zhang*

Nano HELP : Nanodynamics and High Efficiency Lab for Propulsion & Power
Department of Mechanical, Aerospace and Biomedical Engineering,
UT Space Institute, University of Tennessee, Knoxville

*fzhang@utk.edu

Abstract

Polymer electrolyte membrane electrolyzer cells (PEMECs) have been considered as one of the most effective and environment-friendly way for energy storage when coupled with renewable energy sources. In PEMECs, water is electrochemically split into oxygen and hydrogen. At the anode side, the circled water flows over the liquid/gas diffusion layer (LGDL) and diffuses to the triple-phase boundaries (TPBs) - the catalyst layers, where it is decomposed into oxygen, electrons, and protons. The proton will transport through the proton exchange membrane (PEM), reach the cathode catalyst layer, and form hydrogen at the cathode side. Due to limitations of the designs of conventional PEMECs and LGDLs, the microspatial and microtemporal scales of the electrochemical reactions, the phenomena of TPB electrochemical reactions has never been explored in operating PEMECs in-situ.
In this research, an innovatively designed transparent PEMEC was developed, and the thin and well-tuned titanium LGDLs with straight-throughout pores were fabricated. A high-speed and micro-scale visualization system (HMVS) was built for in-situ characterizations. The TPB electrochemical reactions only occurred at the edges adjacent to the good conductive materials. Visualization results reveal the real phenomena inside an operating PEMEC, which can not only help maximize the utilization of catalyst, but also help to optimize the fabrication of catalyst layer. The discovery will have a lot application on improving the electrochemical devices.
Liquid-Solid and Solid-Solid Interfaces in Electrocatalysis from First Principles
Authors: Zeng Zhenhua , Greeley Jeff 
Published: February 2020

Understanding the electrochemical reactions at Liquid-Solid interfaces has been a great and long-term interest but challenge for both experimentalists and theorists. Even though tremendous advances have made through numerous techniques, significant uncertainties relating to the reaction intermediates and reaction mechanism remain. The problem is further complicated when a Solid-Solid interface has been formed either through electrodeposition or de-alloying, as the corresponding interface structures and consequently surface structures of the catalysts are still largely unknown.
In this talk, we will review the methodologies we have recently developed to de-convolute those effects, including a synergistic strategy towards highly accurate prediction of Pourbaix diagram of transition metal (hydroxy)oxides, a simple Morie pattern technique for screening Solid-Solid interface, ab initio molecular simulation to sample Liquid-Solid interfaces and X-ray Photoelectron Spectroscopy simulation to identify the oxygenated species at Liquid-Solid interface.
Next, using monolayer layer (hydroxy)oxide-metal interface as an example, we will demonstrate how the combination of the above techniques could identify the stable phases under various electrochemical conditions. As a case study, we will show the bi-functional role of the interface in promoting hydrogen evolution reaction (HER). As another example, we will show the development of the metal-metal interface during the de-alloying process of Pt-based alloy electrocatalysts.
Finally, we will show the applications of these understandings for the design of new catalysts with improved performances for electrolysis and fuel cell applications.
[1] L. Wang, Y. Zhu, Z. Zeng, C. Lin, M. Giroux, L. Jiang, Y. Han, J. Greeley, C. Wang, and J. Jin, Nano Energy 31, 456 (2017).
[2] Z. Zeng and J. Greeley, Nano Energy 29, 369 (2016).
[3] Y. Ha, Z. Zeng, Y. Cohen, J. Greeley, and A. A. Gewirth, J. Phys. Chem. C 120, 8674 (2016).
[4] Z. Zeng, M. K. Y. Chan, Z.-J. Zhao, J. Kubal, D. Fan, and J. Greeley, J. Phys. Chem. C 119, 18177 (2015).
Hollow Co3O4 Nanopolyhedrons Interwoven with Amorphous Nanowires for Enhanced Lithium Storage and Water Splitting
Authors: Xu Wangwang , Xie Zhiqiang , Wang Zi , Dietrich Grant , Wang Ying 
Published: February 2020

Complex heterostructured nanomaterials receive tremendous attention due to their superior physical and chemical performances than single-structured materials. Nevertheless, it remains a great challenge to precisely control the composition (crystalline or amorphous), size and dimension of the building blocks of hierarchical nanostructures. Herein, we report a scalable method for fabricating crystalline-Co3O4-carbon@amorphous-FeOOH interwoven hollow polyhedrons through thermal treatment paired with solution-phase growth for application as anodes in new-generation lithium ion batteries. In this synthesis, well-defined Co3O4-carbon hollow polyhedrons serve as both oxidizing agent and growth platform for amorphous FeOOH nanowires. The obtained heterostructured hollow polyhedrons exhibit a high reversible capacity of 603 mAh/g after 100 cycles at the specific current of 200 mA/g, showing a capacity fading of only 0.158% per cycle between 10 to 100 cycles, much lower than that of pure Co3O4-carbon hollow polyhedrons (0.604%). When the specific current returns from 2000 mA/g to 50 mA/g, Co3O4-carbon@FeOOH heterostructure maintains a specific capacity of 1120 mAh/g, demonstrating remarkable cycleabilty and high rate capability. Such superior performance is attributed to the synergistic effect of integrated crystal and amorphous components as well as the unique interwoven heterostructure. The design of such an interwoven 3D frame architecture provides new opportunity for obtaining high-performance electrode materials in the field of energy storage.
Reference
Xu, W. W.; Xie, Z. Q.; Wang, Z.; Dietrich, G.; Wang, Y.; Interwoven heterostructural Co3O4–carbon@ FeOOH hollow polyhedrons with improved electrochemical performance. Journal of Materials Chemistry A, 2016, 4, 19011 - 19018
A Hybrid Material Based on Molybdenum Carbide and Nitrogen Doped Carbon for Electrochemical Hydrogen Evolution
Authors: Chakrabartty Sukanta , Raj C Retna 
Published: February 2020

The increase in the global consumption of fossil fuel has adverse impact on the economy and environment. Alternate clean and sustainable energy sources are necessary to meet the future energy requirement. Hydrogen is a promising eco-friendly fuel alternative to the traditional fossil fuel. Hydrogen can be generated by photochemical, electrochemical and photoelectrochemical methods using suitable catalyst. Pt-based catalysts have been conventionally used for the electrochemical hydrogen evolution. However, the use of such catalyst is not encouraged due to high cost and scarcity of Pt. In recent years, several less expensive and earth-abundant electrocatalysts, such as transition metal chalcogenides, phosphides, nitrides and carbides have drawn much attention.1-2 Among them, transition metal carbide, particularly molybdenum carbide (Mo2C) received enormous attention. The electrocatalytic activity of Mo2C can be tuned by controlling the electronic structure, shapes, size and morphology. Achieving high catalytic activity at low overpotential is a main challenge with metal carbide-based electrocatalysts.
We demonstrate a new chemical route for the shape-controlled synthesis of a hybrid material derived from N-doped carbon and Mo2C (Mo2C-N-C) for the electrochemical hydrogen evolution reaction (HER) in acidic and basic medium. The synthetic procedure involves the facile complexation of Mo-precursor with cationic polymer, poly(diallyldimethyammonim chloride) (PDDA) and the subsequent carburization at 800 0C under optimized condition. The hybrid material was characterized by analytical techniques including XRD, XPS, Raman, TEM, etc. Electron microscopic measurements evidence the growth of nanowire bundles with length of 2-3 µm. The electrocatalytic activity was evaluated by recording the polarization curves in 0.5 M H2SO4 and 1 M KOH. We could achieve the benchmark current density of 10 mA/cm2 in acidic and alkaline pH at an overpotential of 136 and 183 mV, respectively. The catalytic performance is comparable to the existing Mo2C-based catalysts.3 The catalytic activity was further evaluated by calculating the Tafel analysis. A Tafel slope of 56 and 61 mV/dec was observed in acidic and alkaline pH, respectively. The Tafel analysis suggests that the electroctalytic hydrogen evolution involves Volmer-Heyrovsky mechanism. The hybrid material is highly durable and it retains its initial activity even after 1000 cycles. The superior performance can be explained by considering the surface morpholgy of Mo2C as well as the synergistic effect between the carbide catalyst and N-doped carbon.

References:

Zeng, M.; Li, Y. J. Mater. Chem. A
2015, 3, 14942−14962.

Zou, X.; Zhang, Y. Chem. Soc. Rev. 2015, 44, 5148–5180.

Gao, W.; Shi, Y.; Zhang, Y.; Zuo, L.; Lu, H.; Huang, Y.; Fan, W.; Liu, T. ACS Sustainable Chem. Eng.
2016, 4, 6313−6321.

Figure 1
Investigating the Role of Fe in Transition-Metal (Oxy)Hydroxide Electrocatalysts for the Oxygen Evolution Reaction
Authors: Enman Lisa J. , Stevens Michaela Burke , Batchellor Adam S. , Vise Ashlee E. , Boettcher Shannon W. 
Published: February 2020

The efficiency of water electrolysis for hydrogen production is limited in part by the slow kinetics of the oxygen evolution reaction (OER).1,2 Nickel-iron and cobalt-iron (oxy)hydroxides have been shown to be the most active, low-cost electrocatalysts for the OER in alkaline conditions.3–5 Although it is evident that Fe is essential for high activity,6,7 its role in the catalytic active site is still largely debated.8,9 We investigate the role of Fe in NiOOH by comparing the effects of Ti, Mn, La, and Ce incorporation on the OER activity and electrochemical behavior of NiOOH in Fe-free 1 M KOH.10 We show that other metal cations in NiOOH can increase its reduction potential in a similar way to Fe, but without the same orders of magnitude increase in OER activity. This suggests that Ni is not likely the active site as its electronic properties are not correlated to activity. We also evaluate the OER activity and Tafel behavior of Fe3+ impurities on different noble metal substrates. We find that the activity varies by substrate suggesting that the local atomic and electronic structure of [FeO6] units play an important role in catalysis of the OER as it can be tuned by substrate interactions. Finally, through in situ and in operando X-ray absorption spectroscopy experiments, we find that the local structure around Fe atoms in Co(Fe)OOH changes during OER while that of Co stays the same. Given that the OER activity on a per Fe basis is independent of [Fe] in Co(Fe)OOH, the potential dependent structural changes further indicate that Fe is essential to the catalytic active site for the OER on transition-metal (oxy)hydroxides.
References
(1) Walter, M. G.; Warren, E. L.; McKone, J. R.; Boettcher, S. W.; Mi, Q.; Santori, E. A.; Lewis, N. S. Chem. Rev.
2010, 110(11), 6446.
(2) Ursua, A.; Gandia, L. M.; Sanchis, P. Proc. IEEE
2012, 100(2), 410.
(3) Trotochaud, L.; Ranney, J. K.; Williams, K. N.; Boettcher, S. W. J. Am. Chem. Soc.
2012, 134(41), 17253.
(4) Burke, M. S.; Zou, S.; Enman, L. J.; Kellon, J. E.; Gabor, C. A.; Pledger, E.; Boettcher, S. W. J. Phys. Chem. Lett.
2015, 6(18), 3737.
(5) Burke, M. S.; Enman, L. J.; Batchellor, A. S.; Zou, S.; Boettcher, S. W. Chem. Mater.
2015, 27(22), 7549.
(6) Corrigan, D. A. J. Electrochem. Soc.
1987, 134(2), 377.
(7) Trotochaud, L.; Young, S. L.; Ranney, J. K.; Boettcher, S. W. J. Am. Chem. Soc.
2014, 136(18), 6744.
(8) Friebel, D.; Louie, M. W.; Bajdich, M.; Sanwald, K. E.; Cai, Y.; Wise, A. M.; Cheng, M.-J.; Sokaras, D.; Weng, T.-C.; Alonso-Mori, R.; Davis, R. C.; Bargar, J. R.; Nørskov, J. K.; Nilsson, A.; Bell, A. T. J. Am. Chem. Soc.
2015, 137(3), 1305.
(9) Chen, J. Y. C.; Dang, L.; Liang, H.; Bi, W.; Gerken, J. B.; Jin, S.; Alp, E. E.; Stahl, S. S. J. Am. Chem. Soc.
2015, 137(48), 15090.
(10) Enman, L. J.; Burke, M. S.; Batchellor, A. S.; Boettcher, S. W. ACS Catal.
2016, 6 (4), 2416.
The Importance of Nickel Hydroxide Structure and Electrolyte Composition in the Kinetics of the Oxygen Evolution Reaction
Authors: Perini Nickson , Godoy João Victor , Ticianelli Edson Antonio 
Published: February 2020

The production of molecular hydrogen from water electrolysis is a challenging issue mainly because of the sluggish kinetics of the oxygen evolution reaction (OER) and the low catalyst stability[1]. For alkaline electrolyzers, nickel hydroxides have been attracting attention due to their high activity for this reaction[2]. In this work, we have synthesized and characterized nickel hydroxide nanoparticles showing enhanced activity for the oxygen evolution reaction when compared to the state-of-art iridium oxide. This is probably due to its amorphous characteristic and the preferential formation of α-phase, confirmed by X-ray diffraction pattern and the cyclic voltammetric profile that presents a redox pair in the range of potential corresponding to the alpha phase (from -0.25 V to 0.45 V vs. normal hydrogen electrode)[3]. The effects of electrolyte composition, comprazing LiOH, NaOH and KOH, were also studied for the nickel hydroxides catalysts in comparison to gold electrode. The results have shown that the configuration of the active sites and thus the kinetics of the OER depend on the interaction between the species in the electrolyte and the catalyst surface.

Acknowledgements:
N.P. and E.T. acknowledge São Paulo Foundation (FAPESP) for financial support (grants No. 2015/18274-5 and 2013/16930-7)

References

[1] M.W. Kanan, D.G. Nocera, In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co2+., Science. 321 (2008) 1072–1075.
[2] O. Diaz-Morales, D. Ferrus-Suspedra, M.T.M. Koper, The importance of nickel oxyhydroxide deprotonation on its activity towards electrochemical water oxidation, Chem. Sci. 7 (2016) 2639–2645.
[3] J. Van Drunen, A.F.B. Barbosa, G. Tremiliosi-filho, The Formation of Surface Oxides on Nickel in Oxalate-Containing Alkaline Media, (2015) 481–491.
Tuning the Electrocatalytic Activity of Perovskite Electrocatalysts for Water Oxidation By Active Site Variation
Authors: Stevenson Keith J , Hardin William G. , Forslund Robin , Johnston Keith P. 
Published: February 2020

Perovskites are a family of complex oxides with the nominal formula AMO3, where A is lathanide or alkali earth and M is typically a transition metal. They are of great interest as replacements for precious metals and oxides used in the oxygen evolution reaction (OER). Perovskite electrocatalysts have been shown to have greater specific activities than precious metals and their oxides, but high mass activities have not yet been realized due to the complex nature of perovskite oxide surfaces and inadequate synthesis techniques which often result in unwanted phase impurities and micron-scale materials. In this presentation we demonstrate the precise control over the chemical composition and structure of a series of perovskite and Ruddlesden-Popper electrocatalysts that are highly active for OER. The reaction pathways are perturbed by the direct modification of the perovskite structure by selective cation replacement and by promotion of catalyst-carbon support-interactions. Specifically the synthesis and electrochemical evaluation of a series of Ruddlesden-Popper (RP) La0.5Sr1.5Ni1-xFexO4+δ will be reported that describe the highest catalytic activities reported for RP/perovskite matierials to date. These results will be described in the context of benchmarking to IrO2 and Pd and definition of the structure, electronic configuration and catalytic pathways. Electroanalytical techniques such as rotating disk electrochemistry and cyclic voltammetry are used in conjunction with materials characterization enabled by dynamic light scattering, electron microscopy, nitrogen sorption, X-ray photoelectron spectroscopy and X-ray diffraction. It will be demonstrated that these highly active perovskite catalysts are an emerging replacement for the precious metal catalysts.
(Invited) Transition Metal and Carbon Composites for Hydrogen Evolution Reaction at Universal Phs
Authors: Zhang Lulu , Shao Minhua 
Published: February 2020

Owing to the climate change and shortage of fossil fuels, renewable energy sources such as solar and wind have become more and more attractive. However, these energies are intermittent and difficult to control. Water splitting provides hope to store these renewable energies in the form of hydrogen through a sustainable method. Up to now, the most popular cathodic electrocatalysts used in commercial solid polymer electrolyte (SPE) electrolyzers are still Pt-based materials that are highly scarce and costly. Therefore, one of the main challenges to generate hydrogen is to develop efficient and cost-effective catalysts toward hydrogen evolution reaction (HER) to replace Pt.
Non-precious metal and nitrogen co-doped carbon-based materials synthesized via different methods are explored for HER at universal pHs. It was found that the HER activity was highly dependent on the preparation method, type of transition metal/non-metal doping and compound formed. The lowest overpotential at 10 mA cm-2 was 190 mV in a 0.5 M H2SO4 solution at a catalyst loading of 0.255 mg cm-2 for Fe3C-C based composite. Density functional theory (DFT) calculations were applied to calculate the hydrogen binding energy and reaction barriers on various possible active sites. This talk will summarize recent systematic work on carbon-based composite materials for HER in my group.