bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Electrochemical Generation of Fuels: Matching Research and Application for Advanced Water Splitting and Other Technologies
Authors: Ayers Katherine E , Gellett Wayne L. , Capuano Christopher B 
Published: February 2020

Electrochemistry is becoming increasingly important in transitioning from primarily fossil fuel based energy sources to more renewable options. This challenge will require a combination of solutions, depending on geography, the mix of renewables, and other factors. The intermittent nature of wind, solar, and other forms of renewable energy, as well as demand fluctuations which do not match the generation capacity, drives the need for modular, distributed energy storage solutions, where electrochemistry can be ideal. However, for very long storage times, conversion of energy to a chemical fuel is often the most practical solution. Electrochemical generation of fuels such as hydrogen, ammonia, and CO2-derived hydrocarbons are all related and have similar R&D challenges. In addition, all of these chemicals have different advantages and disadvantages, and have benefits in different scenarios. This talk will focus on some of the considerations in developing a new electrochemical device, and research challenges applicable to low temperature electrochemical fuel generation.
While fundamental research in understanding electrocatalytic reactions at the molecular level is valuable from a basic science perspective, understanding the application requirements for each market, and pricing structure vs. scale, can guide application of this research to the next logical stage. There is a large application space for fuels and industrial chemicals with widely varying price points based on scale and requirements. For example, different ground vehicle classes (consumer vehicles, heavy duty trucks, fork trucks, industrial equipment etc.,) may each be best served by different fuels depending on power and range requirements as well as customer preferences. Ships and airborne vehicles may have different optimal solutions. Smaller scale or emerging markets such as unmanned vehicles may also serve as easier market entry points.
At the materials discovery stage, all of the above reactions require catalyst design and fundamental understanding in order to achieve high activity and efficiency. Specifically for ammonia and carbon-based fuels, selectivity is a key issue, and structural approaches to control the active site and competition for binding sites are being pursued. Beyond the catalyst, the electrode structure and integration also need to be designed for optimal performance, including effective fluid flow and catalyst access. While the individual catalyst composition and structures will be different, all of these pathways involve hydrogen or oxygen evolution reactions and ion exchange membranes, and can both leverage and inform electrolysis research. Proton’s work in these areas will be discussed, as well as key needs for additional research and collaborations between applied and fundamental science.
Power to Chemicals with High Temperature Solid Oxide Cells: Concepts, Challenges & Prospects
Authors: Costa Rémi , Han Feng , Lang Michael , Sata Noriko , Schiller Guenter 
Published: February 2020

In the context of growing CO2 emissions, the need of more efficient low carbon technologies for energy storage and energy efficiency is pressing. Owing to their unique characteristics, ceramic based solid oxide cells present the valuable feature to be able of operating in fuel cell and electrolyzer mode. If the latter allows primarily efficient conversion of steam into hydrogen, it has the huge benefit of allowing co-electrolysis of CO2 and H2O into a valuable synthetic gas consisting in a mixture of CO and H2 that can be processed downstream into chemicals, for instance via the Fischer-Tropsch process. As practical operation requires a stable function of the electrochemical cells, it is of crucial importance to understand their behavior and the underlying degradation mechanisms in order to be able to identify countermeasures for improving durability.
In this context, the electrochemical behavior of solid oxide cells is being investigated at DLR, from cell to stack level, in different configurations ranging from steam electrolysis to co-electrolysis and reversible operation. In this respect fuel electrode supported cells and electrolyte supported cells have been operated in electrolysis and co-electrolysis mode in different short-term and long-term runs of more than 1000 hours of operation with various gas conditions, operating temperatures and current densities. The electrochemical behavior was investigated by electrochemical impedance spectroscopy while the degradation was monitored by chronopotentiometry. Post-test microstructural analysis of functional ceramic layers was systematically performed with scanning electron microscopy in order to correlate possible microstructural changes with degradation phenomena.
Among others, it is found that the standard Nickel / Yttria-Stabilized-Zirconia cermet in fuel electrode supported cells suffers irreversible degradation through Nickel agglomeration and Nickel depletion, a phenomenon which was found to be correlated with temperature and current density. In electrolysis operation, cracking within the electrolyte along the air electrode is often observed. The main degradation features will be presented and discussed on the basis of the key identified drivers. Advanced materials solutions to mitigate the degradation issues will be presented and prospective applications will be introduced.
Modeling and Test-Bed Development of Vapor Feed Electrochemical CO2 Reduction Devices
Authors: Xiang Chengxiang("CX") 
Published: February 2020

Electrochemical CO2 reduction in vapor feed configurations has some unique opportunities and challenges in relative to aqueous electrolyte based devices. In particular, the vapor feed devices could achieve significantly higher operational current densities and could operate at high pH ranges that were un-favorable for aqueous electrolyte based devices due to the depletion of dissolved CO2 at the electrode surface.
In this talk, I will show some recent results on modeling and test-bed development of two vapor-feed device configurations. A multi-physics agglomerate model that describes the operational details for a gas diffusion electrode (GDE) based device, including the local CO2 concentration profiles, pH gradients, polarization losses, CO2 utilization challenges and impact on Faradaic efficiency due to hydrogen evolution reaction, will be discussed in detail. The modeling results were then compared to the performance of Cu nanoparticle based GDEs. As predicted by the model, Cu-GDEs operating at alkaline conditions for CO2 reduction and CO reduction exhibited significantly higher partial current density for C2 products generation than the planar analogy. The transformation of the Cu catalyst in GDE under various electrochemical potentials for CO2 reduction was also investigated by in situ X-ray absorption spectroscopy. In addition, a proof-of-concept, full vapor feed device for CO2 reduction to formic acid using a reverse-configured bipolar membrane to achieve advantageous product separation will be discussed.
Beyond Flatland: Exploring 3D Cu Catalysts for CO2 Reduction
Authors: Vedharathinam Vedasri , Qi Zhen , Stadermann Michael , Biener Juergen , Biener Monika M. 
Published: February 2020

The electrochemical CO2 reduction reaction (CO2RR) has become a promising path forward to a carbon neutral energy cycle by combining carbon capture with hydrocarbon production, especially if excess power from regenerative resources such as wind and solar is available and used. The key obstacle for deployment of the one-step electrochemical CO2RR technology is the development of low-cost electrocatalysts that facilitate energy-efficient production of hydrocarbons from CO2 with high selectivity and long-term stability. Here, copper has emerged as the most promising catalyst for the formation of hydrocarbons at ambient pressures and temperatures.
We have developed a unique expertise in the synthesis of nanoporous metal catalysts including nanoporous Cu (npCu) made from CuMn and CuZn alloys, Cu nanocube surface functionalizations and Cu-oxide/Cu nanowire forests (Fig. 1). Preliminary CO2RR tests of these materials have confirmed that oxidized npCu electrodes have a significantly increased transient reactivity towards the electrochemical reduction of CO2. We will discuss results using a novel electrochemical cell geometry that is designed to take full advantage of the high surface area of the catalyst.

Fig. 1: (a) NpCu prepared by dealloying CuZn alloys; (b) Cu nanocube surface functionalization of npCu; (c) Cu-oxide nanowires grown on Cu foam formed by annealing in air (1h @ 500C).
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

Figure 1
Electrochemical Reduction of CO2 to Formate on Sn@Cu By Electrodeposition with Hydrogen Bubble Template
Authors: Hou Xiaofan , Liu Junyu , Zhang Qi , Zhou Yue , Qiao Jinli 
Published: February 2020

In recent years, the emissions of carbon dioxide (CO2) into atmosphere caused by industrial production has been considered to be one of the main causes of global warming, which has recently attracted much attention1. Electrochemical reduction of CO2 could provide an attractive solution to this climate issue with CO2 converted into useful fuels such as formic acid, methane, methanol, ethylene, etc., which represents a value-added path that can simultaneously produce alternative fuels and remedy the carbon emissions generated by conventional fuels2. Metal catalysts have been demonstrated effectively and widely used materials to obtain formate by reducing CO2. Among these metals, tin or copper-tin alloys are excellent candidates regarding to CO2 electroreduction to produce formate fuel. However, the fabrication production of catalysts is complicated for practical application, as the synthetic process need high-temperature calefaction or the addition of expensive additives3.
Electrodeposition with hydrogen bubble template in aqueous solution is a facile, low-energy method, which can easily create a 3D structure so that can provide large specific surface area on the substrate. Meanwhile, the porous foam attributed to concurrent hydrogen bubbles with different deposition time has a distinct impact on the catalytic activity and selectivity during CO2 electrochemical reduction. By applying electrodeposition methods, we have successfully synthesized the Sn@Cu catalysts, which was controlled by simply adjusting the electrodeposition time. As demonstrated by both CV and LSV results, highly selective HCOO- production (Faradaic efficiency = 86.7%) can be realized at a potential of -1.6 V vs. SCE with really high current density greater than 10 mA cm-2.
References
[1]. J.L. Qiao; M.Y. Fan; Y.S. Fu; Z. Bai; C. Ma; Y. Liu; X.D. Zhou, Electrochim. Acta, 153, 559 (2015)
[2]. Y. Wang; J. Zhou; W. Lv; H. Fang; W. Wang, Appl. Surf. Sci., 362, 394 (2016)
[3]. X. Zhang; T. Lei; Y.Y. Liu; J.L. Qiao, Appl. Catal., B,
218, 46(2017)
Enhanced CO2 Electrochemical Conversion at Bi-Modified Pb Foams
Authors: Guay Daniel , Fan Mengyang , Garbarino Sebastien , Botton Gianluigi A. , Tavares Ana C 
Published: February 2020

CO2 conversion methods to remediate anthropogenic emissions appear promising, as they offer the potential to produce liquid and gaseous fuels for use either in the aeronautics industry, or as a chemical storage method for intermittent energy produced by windmills and photovoltaic panels. Fuel synthesis may be achieved via either the production of a syngas mixture (H2 and CO) through the water gas shift reaction and subsequent conversion into hydrocarbon fuel, or by direct electrochemical reduction of CO2. Direct electrochemical conversion of CO2 into value-added products is a low-temperature process, with the advantage of requiring relatively simple equipment.
Formic acid, or formate salts, are used in a variety of chemical processes such as electrowinning, leather tanning, and aircraft de-icing. Alternatively, formic acid and formate salts may be considered as a hydrogen storage medium. On top of that, direct formic acid, and more recently direct formate, fuel cells, have been investigated as they demonstrate significant benefits over methanol fuel cells, including higher open circuit voltage and lower crossover.
Pb and Bi are promising catalysts with good selectivity for formate. In the case of lead, it can be prepared in the form of dendrites with nanometre-sized tips. Local high electric fields can exist at the tip of these dendrites that can induce a concentration of electrolytes which in turn leads to improve electroreduction of CO2 [[1]]. Bismuth is non-toxic and has negligible environmental impact. It has few commercial applications, and its price has been low and relatively stable in recent years.
In this work, we studied the activity and stability for CO2 electroreduction onto high surface area metallic Pb films. The latter Pb films were further functionalized by Bi overlayers to enhance CO2 reduction properties. For both materials, the material films were prepared through a potentiostatic method. Both types of films were extensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and x-ray diffraction (XRD), while electrochemical activities were characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and potentiostatic measurements.
[1] M. Fang, S. Garbarino, G.A. Botton, A.C. Tavares and D. Guay, J. Mater. Chem A 5 (2017) 20747-20756
Engineered Electrolyte-Electrocatalyst Nanocomposites for Enhanced CO2 Electroreduction
Authors: Elgammal Ramez A. , Zawodzinski Thomas A 
Published: February 2020

The development of a viable approach to capture, store, and convert carbon dioxide into fuels and chemicals may offer a means to mitigate climate change while also creating value added commodity chemicals. Critical bottlenecks in existing technologies that have impeded commercialization of CO2 electrosynthesis include catalysts with high overpotentials and limited selectivities. Furthermore, current approaches often employ PEM-based electrolyzers that suffer from low CO2 solubility in acidic aqueous solutions, limiting mass transport and reaction rates, or AEM-based systems which have much higher CO2 solubilites in alkaline electrolytes, but have the added problem of membrane poisoning by bicarbonate and carbonate.
We have recently developed an electrochemical reactor that overcomes many of the shortcomings that have limited the above technologies. Our preliminary results suggest that onset potentials for CO2 reduction are more than 200 mV lower than with current densities in excess of 150 mA/cm2 at -1 V vs RHE. We have examined several cathode electrocatalysts and some of the most promising include a series of nanostructured mixed and/or doped transition metal and main group metal oxides that also suppress the hydrogen evolution reaction. We will present detailed electrochemical and structural studies and will comment on possible reaction mechanisms as well as the key features of the reactor that enable the enhanced kinetics.
Employing Mg Powder As a Scavenger to Improve Mg Electrolytes for Mg Rechargeable Batteries
Authors: Luo Jian , Bi Yujing , Liu T. Leo 
Published: February 2020

Electrochemical performance of Mg electrolytes is highly sensitive to water and other impurities. The water sensitivity of a MgCl2/AlCl3 electrolyte in DME was demonstrated, showing increased overpotential and poor Coulombic efficiency for Mg deposition. Mg powder treatment was found to be very effective and convenient to remove deleterious impurities present in MgCl2/AlCl3 electrolytes to yield unprecedented electrochemical performance for reversible Mg deposition including 100% Coulombic efficiency, low overpotential (< 200 mV), and high anodic stability (up to 3.8 V). It is also found the Mg powder scavenger is also effective for other Mg electrolytes, highlighting the generality of the Mg powder treatment approach. The working mechanism of the Mg powder scavenger will be discussed. In addition, we will show that ternary Mg/MgCl2/AlCl3 (MMAC) electrolytes are reliable for Mg battery applications.

References:

(1) Luo, J; .He, S.; Liu, T. L.* ACS Energy Letters 2017, 2, 1197-1202.
(2) He, S.; Luo, J. Liu, T. L.*, J. Mater. Chem. A 2017, 12718-12722.
(3) He, S.; Neilson, K. V.; Luo, J..; Liu, T. L.*, Energy Storage Mater 2017, 8, 184-188.
Tuning the Surface Properties of Li Metal Anode in Li-S Batteries Via Metal Fluoride-Based Artificial Solid Electrolyte Interphase
Authors: Ren Yuxun , Xiong Cheng , Jiang Haoran , Zeng Lin , Xu Jianbo , Zhao Tianshou 
Published: February 2020

Abstract
Lithium-sulfur (Li-S) batteries promise the next-generation energy storage. However, one of the issues facing Li-S batteries is the high reactivity of the Li metal, leading to serious interfacial side reactions; the other is the dendritic Li growth that can usually breach the solid electrolyte interphase (SEI) applied for mitigating side reactions. To address these issues, we propose the indium fluoride-based artificial solid electrolyte interphase with tunable surface properties. Over the initial charging, InF3 nanoparticles coated on the Li anode surface can be lithiated to form a layer of nanoporous lithium/indium alloy (LixIn) encapsulating lithium fluoride (LiF) nanoparticles (3Li++3e-+InF3→3LiF+In) as shown in Figs. 1(a, b). The tightly anchored LixIn layer well attaches LiF on the anode surface during Li stripping/plating, while LiF with a higher Young’s modulus physically suppresses dendritic Li growth. Both LixIn and LiF provide facile adsorption towards Li atoms as well as high Li+ conductivity, inducing uniform Li plating [1-4]. In addition, both materials are stable with corrosive electrolyte containing polysulfides and shield Li anode from side reactions. Tuning the SEI surface properties via adding other metal fluorides such as BiF3 and AlF3, we further show the possibility to further enhance the Young’s modulus and flexibility for the SEI. Applying the rationally designed artificial SEI, substantial enhancement in terms of Li stripping/plating stability (Fig. 1c) and Li-S battery cyclability is achieved even using LiNO3-free electrolyte and the gas evolution arising from interfacial electrolyte decomposition is suppressed [5]. With enhanced mechanical strength and chemical stability, the metal fluoride-based artificial SEI paves a new way in developing durable and safer Li-S batteries.
Key words: Li metal; artificial solid electrolyte interphase; dendrite; side reaction; metal fluoride.
Acknowledgement
The work described in this paper was fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. T23-601/17-R)
Reference
[1] Y. Ren, T. Zhao, M. Liu, Y. Zeng, H. Jiang, Journal of Power Sources, 361 (2017) 203-210.
[2] X.Q. Zhang, X. Chen, R. Xu, X.B. Cheng, H.J. Peng, R. Zhang, J.Q. Huang, Q. Zhang, Angewandte Chemie, 129 (2017) 14395-14399.
[3] M. Liu, Y. Ren, H. Jiang, C. Luo, F. Kang, T. Zhao, Nano Energy, 40 (2017) 240-247.
[4] Y. Ren, T. Zhao, H. Jiang, M. Wu, M. Liu, Journal of Power Sources, 347 (2017) 136-144.
[5] A. Jozwiuk, B.B. Berkes, T. Weiß, H. Sommer, J. Janek, T. Brezesinski, Energy & Environmental Science, 9 (2016) 2603-2608.

Figure 1
In Situ Polysulfide Detection in Lithium Sulfur Batteries
Authors: Jones John-Paul , Jones Simon C. , Krause Frederick C. , Pasalic Jasmina , Bugga Ratnakumar V 
Published: February 2020

Lithium-sulfur (Li/S) batteries promise significant specific energy improvements over traditional lithium-ion technology resulting from the high theoretical capacity of both the sulfur cathode and the lithium anode. However they are constrained by low voltage, safety issues due to the lithium anode, charge retention, and cycle life to name a few issues. A variety of these drawbacks are frequently attributed to the so-called “polysulfide shuttle” where partial discharge products from the cathode (polysulfide species such as Li2S6, Li2S4, etc.) dissolve in the electrolyte and migrate to the anode where they wreak havoc.1–4 Many approaches have been developed to mitigate this issue, however few attempts have been made to measure the amount of polysulfide in the electrolyte, particularly during cycling in a representative cell. Here we describe an electrochemical in situ method for detecting and quantifying polysulfide species in the electrolyte of experimental Li/S cells during operation. This method has been applied to experimental Li/S and lithium sulfur-molybdenum disulfide (Li/S-MoS2) cells developed previously in our laboratory.5 High concentration electrolytes and ceramic coated separators were also investigated using this method as they have also been shown to influence the performance (cycle life in particular) of Li/S cells.6 The method utilizes an auxiliary electrode inserted into the electrolyte for a quantitative determination of the redox behavior of the polysulfides. Several interesting trends were observed using this method, including that Li/S-MoS2 cathodes, ceramic coated separators and concentrated electrolytes all display lower concentration of polysulfide compared to the baseline Li/S cells. The quantity of polysulfide species changes during discharge, increasing dramatically during the second discharge plateau. This technique can thus be used to determine the efficacy of new modifications (for example to the cathode or separator) designed to improve sulfur sequestration within or near the cathode

Acknowledgement:

This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The authors acknowledge the funding support of Army (CERDEC).
© 2017 California Institute of Technology. Government sponsorship acknowledged.

References:

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C. Zu and A. Manthiram, J. Phys. Chem. Lett., 5, 2522–2527 (2014).

D. Moy, A. Manivannan, and S. R. Narayanan, J. Electrochem. Soc., 162, 1–7 (2015).

D. Moy and S. R. Narayanan, J. Electrochem. Soc., 164, A560–A566 (2017).

R. V. Bugga, S. C. Jones, J. Pasalic, C. S. Seu, J.-P. Jones, and L. Torres, J. Electrochem. Soc., 164, A265–A276 (2017).

R. Bugga, J. Jones, S. C. Jones, F. C. Krause, J. Pasalic, D. S. Ganapathi, M. Hendrickson, and E. J. Plichta, 165, 6021–6028 (2018).