bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposition of Ag-W Alloy Films from Ionic Liquid for Electrical Contacts
Authors: Höhlich Dominik , Müller Markus , Mehner Thomas , Scharf Ingolf , Lampke Thomas
Published: February 2020

The global e-mobility market is experiencing strong growth. As a driving force, China increased its share of electric vehicles by nearly 400% from 0.3 million in 2015 to 1.25 million in 2018. The increase in registrations of electric vehicles in the US shows a similar percentage, from 0.14 to 0.36 million in the last five years. Within twenty years, electric vehicles may account for 45 percent of total car sales worldwide. In the automotive industry, the present motor performance along with its steady increase suggests using very powerful electric motors with, at least temporary, very high power consumption. For the required high currents, new coating concepts for build-in electric contacts are necessary. By far, silver-tungsten alloys are the most popular contact materials. Tungsten is the choice of material when currents are switched. Sintered or infiltrated tungsten-silver contacts can be used from the 1 to 800 kV range. At high voltages, arcing can briefly occur at the contacts during switching with currents up to 100 kA, which results in very high temperatures (> 10,000 K). In silver-tungsten alloys, the ability of tungsten to withstand thermal, mechanical, and electrical wear, combined with the high electrical conductivity of silver make them the appropriate materials. However, the electrodeposition of these alloys from aqueous solutions is not yet state of the art. This presentation shows a way to produce these contact materials by electrodeposition from non-aqueous ionic liquids. Silver-tungsten alloy films for application as electrical contacts were prepared using tungsten hexachloride, silver chloride and anhydrous 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic-liquid solution with aluminium chloride in different ratios. The deposition takes place outside the glove box. The crystalline structure of the alloys were investigated by X-ray diffraction (XRD). The chemical composition was characterized by scanning electron microscopy (SEM) and inductively-coupled plasma optical emission spectroscopy (ICP-OES). The shown electrodeposition of tungsten-base alloys with silver make the time-consuming and expensive sintering process redundant and lead to thin, lightweight, and low-cost contacts while saving resources.
(Invited) Electrochemically Induced Phase Separation in Ionic Liquid Mixtures
Authors: Endres Frank
Published: February 2020

Liquid-liquid phase separation is mainly dependent on temperature and composition. Electric fields have also been shown to influence demixing of binary liquid mixtures. However, a puzzling behavior that remains elusive is the electric field–induced phase separation in ion-containing solvents at low voltages, as predicted by Tsori and Leibler. Here, we report an experimental study of such a phenomenon in ionic liquid–silane mixtures, which not only results in phase separation at the electrode-electrolyte interface (EEI) but also is accompanied by deposition of porous structures of micrometer size on the electrode. This multiscale phenomenon at the EEI was found to be triggered by an electrochemically induced process. Using several analytical methods, we reveal the involved mechanism in which the formation of new Si–N bonds becomes unstable and eventually decomposes into the formation of silane-rich and silane-poor phases. The deposition of porous structures on the electrode surface is therefore a realization of the silane-rich phase. The finding of an electrochemically induced phase separation not only brings a paradigm shift in understanding the EEI in ionic liquids but also provides alternative strategies toward designing porous surfaces. Further examples like e.g. macroporous conducting polymers will be presented.

reference: Abhishek Lahiri, Niklas Behrens, Giridhar Pulletikurthi, Arik Yochelis, Edwin Kroke, Tong Cui, Frank Endres, Science Advances 26 Oct 2018: Vol. 4, no. 10, eaau9663

DOI: 10.1126/sciadv.aau9663
Treatment of a Highly Concentrated Industrial Effluent with a Pre-Pilot Electrochemical Reactor – Approach to a Practical Application
Authors: García-Rodríguez Orlando , Zhu Si , Olvera-Vargas Hugo , Wang Zuxin , Lefebvre Olivier
Published: February 2020

Electrochemical advanced oxidation processes (EAOPs) rely on the non-selective and strong oxidant •OH to mineralize organic pollutants in contaminated effluents [1]. Among them, electro-Fenton (EF) has proven efficient and robust for the degradation of recalcitrant organic pollutants [2]. However, most of the studies on EF are limited to reactors with volumes below 1 L and synthetic effluents. Aiming at practical applications, a pre-pilot scale EF reactor is disclosed here with the highest working volume (50 L) among all reports to date. The reactor incorporated commercial BDD or DSA anodes, as well as our patented cathodes , made of carbon fibers coated with graphene. A local company provided us with real wastewater, originating from the fabrication of flat sheet membranes, with an initial TOC of 10,000 ppm and containing hexane, n, n-dimethylformamide (DMF), trimesoyl chloride (TMC), m-phenylene diamine (MPD) and isopropyl alcohol. One of the biggest challenges of scaling up the EF system was to maintain the same efficiency (in terms of mineralization and energy consumption) as in smaller scale laboratory setups. Figure 1A shows the main results at different stages of scaling up the process. The initial lab-scale stage consisted of beaker experiments with a mineralization efficiency of 98% in 24 h. The bench-scale stage, conducted in a specially-designed flow-through recirculated reactor, saw a decrease in mineralization efficiency (36.2%) and an increase in energy consumption (38.4 Wh g-1 of TOC ), which laid the foundations to improve the engineering design of the pre-pilot scale reactor, using a flow simulation CAD software (Fig. 1B). As a result, the energy consumption decreased to 12.8 Wh g-1 of TOC in that final setup and the 24-h mineralization yield attained 64.8%. In conclusion, we demonstrated the successful scale-up of EF for treatment of real industrial wastewater with high organic load, with good mineralization and energy consumption efficiencies.

References

[1] H. Olvera-Vargas, N. Oturan, M.A. Oturan, E. Brillas, Electro-Fenton and solar photoelectro-Fenton treatments of the pharmaceutical ranitidine in pre-pilot flow plant scale, Separation and Purification Technology, 146 (2015) 127-135.

[2] O. Garcia-Rodriguez, Y.Y. Lee, H. Olvera-Vargas, F. Deng, Z. Wang, O. Lefebvre, Mineralization of electronic wastewater by electro-Fenton with an enhanced graphene-based gas diffusion cathode, Electrochimica Acta, 276 (2018) 12-20.

Figure 1
Electrochemically Enhanced Processes for Leather Tanning
Authors: Gibertini Eugenio , Rossi Filippo , Magagnin Luca , Masi Maurizio
Published: February 2020

Leather production involves several operations where the tanning plays the major role in improving the durability of leather products by forming durable linkages between the tanning agents and the collagen. Different agents are used, but the most important is chromium. However, nowadays there is a growing demand for a cleaner, but still effective alternative for production processes. In the traditional tanning process, the penetration of these agents inside the leather is governed by diffusion based on a concentration gradient. In this study, a new tanning approach is proposed, taking advantage of the intensification effects of an applied electric field, within two electrodes in solution, on the tanning method [1]. An improvement in the efficiency is observed due to the positive charge acquired by the agents (Cr, Ti, Zr and Fe) complexes in tanning solutions and the possibility to control the bath pH by exploiting the side reactions at the two electrodes. The new electrochemically intensified tanning technique shows better performances than the standard one, resulting in a larger agent uptake in the same amount of time, leading to a shorter process time. The intensification of the tanning process will be justified in light of a simulation model of the involved phenomena.

Enhanced chrome tanning process, Patent Pending
A High Efficiency Osmotic Energy Harvester with Vertically Aligned Boron-Nitride-Nanopore Membrane
Authors: Kim Sangil , Pendse Aaditya , Cetindag Semih , Behura Sanjay , Berry Vikas , Shan Jerry
Published: February 2020

Application of the abundant salinity-gradients in the environment, motivated by the Gibbs free energy of mixing fresh and salt water, has been under intensive investigation for clean-energy harvesting. Globally, there is a potential of at least 2.6 TW of power that could be generated at coastal estuaries from the ion-concentration gradient. Recent investigation on an energy conversion efficiency of single boron nitride nanotube (BNNT) has revealed the huge potential of an efficient exploitation of electrokinetic phenomena in nanofluidic systems for energy harvesting.

Here, for the first time, we demonstrate rationally designed nanostructured vertically aligned boron-nitride-nanopore membranes (VA-BNNP) which can efficiently harness osmotic power from salinity gradient. A thin hexagonal boron nitride (hBN) layer was uniformly deposited within the pores of anodized alumina substrates by low-pressure chemical vapor deposition which produced first-ever macroscopic VA-BNNP membrane with high nanopore density, up to ~108 pores/cm2. Cross-sectional scanning-electron-microscope (SEM) images show the hBN layer (~35 nm) was uniformly deposited along the pores without excessive hBN on the top surface, ensuring that most pores remained open. In addition, the results of scanning confocal Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) showed the high quality of the hBN layers in the AAO pores. We investigated the power generation of the macroscopic VA-BNNP membranes at different pH and salinity concentrations. The power generation per unit pore area increased as the salt concentration and pH increased. The highest power density of the membrane was up to ~100 W/m2 which is two orders of magnitude higher than that of other macro-scale, salinity gradient driven, power generation system reported so far. In addition, we also elucidate the fundamental ion transport mechanism in BN nanopore using the molecular dynamic simulations to support to the experimental power density values. These findings indicate the great potential of large-area VA-BNNP membranes as next-generation nanostructured membranes for renewable energy harvesting.
pH Swing Cycle for CO2 Capture Electrochemically Driven through Proton-Coupled Electron Transfer
Authors: Kwabi David G. , Aziz Michael J.
Published: February 2020

We propose and perform a thermodynamic analysis of the energetic costs of CO2 separation from flue gas using a pH swing created by electrochemical redox reactions involving proton-coupled electron transfer from molecular species in aqueous electrolyte. Electrochemical reduction of these molecules results in the formation of alkaline solution, into which CO2 is absorbed; subsequent electrochemical oxidation of the reduced molecules results in the acidification of the solution, triggering the release of pure CO2 gas. We examined the effect of buffering from the CO2-carbonate system on the solution pH during this pH swing cycle, and thus on the open-circuit potential of a hypothetical electrochemical cell in a 4-step CO2 capture-release cycle. The thermodynamic minimum work input varies from 16 to 75 kJ/molCO2 as throughput increases, for both flue gas and direct air capture, with the potential to go substantially lower if CO2 capture or release is performed simultaneously with electrochemical reduction or oxidation. These values are compared with those for other separation methods. We also discuss the properties required of molecules that would be suitable for such a cycle, and preliminary experimental data from a cycle run using one such molecule.
Insights into Carbonate Fuel Cell Operation Under Carbon Dioxide Capture Conditions
Authors: Elsen Heather , Sawicki Conrad , Barckholtz Tim , Rosen Jonathan
Published: February 2020

Providing for increasing global energy needs while managing carbon dioxide emissions is the dual energy challenge the modern world faces. In order to meet this challenge, reliable and dispatchable low carbon energy sources are a likely component. For many scenarios, this suggests that cost effective carbon dioxide capture will be a key technology.[1] Carbon capture with carbonate fuel cells (CFCs) may be one such technology option.[2]

Carbonate fuel cells concentrate carbon dioxide from the cathode to the anode as part of their normal operation, effectively doing both carbon capture and low carbon power generation in a single process. (see Figure 1) When generating power, typical carbon dioxide concentrations fed to the CFC cathode tend to be higher than carbon dioxide emissions of many industrial processes. This means that if we want to capture that carbon dioxide, we need the fuel cell to operate at lower carbon dioxide concentrations than it typically does. For carbon capture operations, cathode inlet carbon dioxide concentrations could be as low as 4%. Additionally, under typical power generation operations, CFCs only capture a fraction of the carbon dioxide (<50%) fed to the cathode, where for carbon capture rates may be as high as 90%. Together these two constraints (low initial concentration and higher capture) results in very low carbon dioxide concentrations in the cell, particularly at the cathode outlet. This may impact the fundamental chemistry of the process.

Carbon dioxide capture at 4% and lower was tested in a fuel cell, specifically designed to minimize mass transport effects external to the active cell components. Carbon capture was demonstrated at a range of carbon dioxide concentrations ranging from standard operation for power generation (>10%) to <1%. Additionally, oxygen concentrations and current densities were varied over likely operational ranges. We demonstrate that under most circumstances, operations under carbon capture conditions proceed via a similar mechanism to those under power generation conditions. However, in harsh or extreme conditions, where carbon dioxide concentrations are low (<0.5%) and/or current densities high, alternative mechanisms appear. We demonstrate how the CFC performs when these alternative mechanisms are present. Additionally, our findings suggest that they appear to utilize water in place of carbon dioxide and allow the cell to operate at conditions beyond theoretical complete carbon capture.

[1] IEA World Energy Outlook 2018; Bloomberg New Energy Finance, New Energy Outlook 2018

[2] Ghezel-Ayagh H., Jolly S., Patel D., Hunt J., Steen W., Richardson C., Marina O., (2013) A Novel System for Carbon Dioxide Capture Utilizing Electrochemical Membrane Technology ECS Transaction Vol 51 (1) 265-272

Figure 1
(Invited) Nanocrevasse-Rich Carbon Fibers for Scalable Production and Stable Performance of Lithium and Sodium Metal Anodes
Authors: Kim Min-Ho , Go Wooseok , Wi Tae-Ung , Kim Youngsik , Lee Hyun-Wook
Published: February 2020

The metallic lithium (Li) and sodium (Na) anodes have long been considered as ideal anodes for high energy density batteries due to its high theoretical capacity and lowest reduction potential. However, the challenges induced by dendritic growth on metallic Li and Na anodes hinder the practical applications. Finding a stable host structure with polar functional groups is an essential strategy to prevent the Li and Na dendrite growth with improved electrochemical performance. Recently, many researchers have concentrated on development of host structure for storing the Li/Na metal. Nevertheless, complexity and inconvenience of the synthetic process still require further improvement of Li/Na metal anodes. In this talk, we will introduce a facile synthetic method to fabricate alkali metal/carbon composites which contain nanocrevasses in carbon fibers to facilitate the penetration of molten alkali metal via capillary forces. When the molten alkali metal is contacted to the carbon fibers with rGO-like crevasses, the metallic liquid infiltrates into the fine gaps within a few seconds. As well, the nanocrevasses provide a pretty large surface area which is enough to lower the specific current, ultimately leading to suppression of dendritic formation. The resulting alkali metal/carbon composites exhibit stable long-term cycling over hundreds of cycles. In addition, Unlike previous studies that focused on improving the performance of metal batteries, we carried out the test after applying the composite to actual equipment with scalable production process using recycled metal waste. Thus, the addition of nanocrevasses to carbon fiber as a scaffold for alkali metals can generate environmentally friendly and cost-effective composites for practical electrode applications

References

Go, W.; Kim, M.-H.; Park, J.; Lim, C.H.; Joo, S.H.; Kim, Y.; Lee, H.-W. Nano Lett. 2019, 19, 1504-1511.

Lin, D.; Liu, Y.; Liang, Z.; Lee, H.-W.; Sun, J.; Wang, H.; Yan, K.; Xie, J.; Cui, Y. Nat. Nanotechnol.
2016, 11, 626-632.

Zhang, R.; Chen, X.; Chen, X.; Cheng, X.; Zhang, X.; Yan, C.; Zhang, Q. Chem. int. Ed.
2017, 56, 7764-7768.

Yun, J.H.; Kim, J.H.; Kim, D.K.; Lee, H.-W. Nano Lett.
2018, 18, 475–481.

Figure 1
Role of Li Distribution in High Li Conductivity of Li
x
(Ge,P)3S12
Authors: Hinuma Yoyo , Yajima Takeshi , Hori Satoshi , Iwasaki Rui , Hiroi Zenji , Kanno Ryoji
Published: February 2020

Li
x
(GeP)2S12 (LGPS) is a lithium superionic conductor with the obvious potential application as an electrolyte for all-solid-state batteries that could be safer and have higher power compared to conventional batteries using liquid electrolytes. Li10GeP2S12 shows an exceptionally high conductivity of 12 mS/cm at room temperature [1], and doubling of the conductivity to 25 mS/cm was attained in the related compound Li9.54Si1.74P1.44S11.7Cl0.3 [2]. LGPS has a complicated structure. The backbone is a framework of GeS4 and PS4 tetrahedra where there are (Ge,P) shared sites and P-only sites. Li is four-folded coordinated with S and occupy four types of sites, Li1 to Li4. (Li1)S4 and (Li3)S4 form a one-dimensional chain and this is considered to be the primary Li diffusion route. The original article [1] claimed that the Li1 site is clearly double-split while the other Li sites are not split. However, in our presentation we show that the Li3 site is actually double-split at room temperature and triple-split at 10K.

Li splitting means that there are more local minima for Li, which in turn results in increased complexity in Li migration paths. Understanding and controlling of Li splitting is important to further enhance Li conductivity. Both Li1 and Li3 sites, which are found to split, take part in the primary Li conduction path and therefore the intriguing high Li conductivity of LGPS should be strongly influenced by fine details of the Li potential. Our first principles calculations show that that neither Li1 nor Li3 sites splits in Li12Ge3S12 where all Li sites are occupied, and reducing the Li concentration, or introducing Li vacancies, was found to be necessary for splitting of these Li sites.

Kamaya, N.; Homma, K.; Yamakawa, Y.; Hirayama, M.; Kanno, R.; Yonemura, M.; Kamiyama, T.; Kato, Y.; Hama, S.; Kawamoto, K.; Mitsui, A., A lithium superionic conductor. Nat. Mater. 2011, 10 (9), 682.

Kato, Y.; Hori, S.; Saito, T.; Suzuki, K.; Hirayama, M.; Mitsui, A.; Yonemura, M.; Iba, H.; Kanno, R., High-power all-solid-stae batteries using sulfide superionic conductors. Nature Energy 2016, 1 (4), 16030.
Lithium Metal Electrode — Understanding Its Unique Characteristics and Functions
Authors: Pawar Gorakh , Liaw Boryann , Dufek Eric J.
Published: February 2020

Lithium metal electrode (LME) is attractive for the next generation of commercial high-energy rechargeable lithium battery (RLB) design and development. As a light element with a very reducing electrochemical potential, Li metal certainly has the unique characteristics that also present challenges for its application in RLBs. To overcome technical barriers with LME such as the dendrite formation that causes uneven current distributions, excessive solid electrolyte interphases (SEI) formation that consumes Li inventory, and formation of inactive Li metal in granular forms that induces safety hazards, more fundamental understanding of the unique characteristics of LME and its impact on functions in performance in RLBs is critical. Here, we present some recent work based on temporally-correlated reactive molecular dynamics simulations to understand the Li deposition and the associated nucleation and growth process on LME or graphitic electrode surfaces. Such a study provides some intriguing perspectives on how Li reacts with electrolytes on LME and conventional graphitic electrodes in the RLB operation. Such an insight could help improving our strategy to deal with LME problems and provide functional improvements for LME’s application in RLBs. This presentation is dedicated to Professor Robert Huggins for his life-long teaching of the fundamentals on solid state ionics and its implications in understanding the electrochemical behavior of Li in RLB applications.
The Pyridinic-to-Graphitic Conformational Change of Nitrogen of Graphitic Carbon Nitride on Lithium Coordination during Lithium Plating
Authors: Jeon Yuju , Kang Sujin , Joo Se Hun , Park Sung O , Cho Minjae , Kwak Sang Kyu , Lee Hyun-Wook , Song Hyun-Kon
Published: February 2020

The reversibility of lithium plating/stripping should be guaranteed in lithium metal batteries. Seriously polarized lithium growth during plating leads to the dendritic evolution of lithium metal due to the uneven current distribution on the electrically conductive surface. Artificial protective layers covering electrodes (e.g., polymer film on copper foil) have been used to narrow the gap of the current density between positions on the conductive surface. Herein, we incorporated an active ingredient to attract lithium ions into the dendrite-suppressing layer. Pyridinic nitrogen of graphitic carbon nitride (g-C3N4) served as the lithium ion affinity center. Conformation of the nitrogen was changed from pyridinic to graphitic in the presence of lithium ions, which confirms the coordination of lithium ion to the pyridinic nitrogen. Lithium metal was plated between the g-C3N4 layer and the copper current collector (or the lithium metal). The homogeneous lithium nucleation expected from the active role of the pyridinic nitrogen on regulating ionic pathways suppressed the dendritic growth of lithium metal and decreased the overpotential required for the initial metal nucleation. Due to the top-down ion flux regulation on the uppermost surface (or tip) of lithium metal, the reversibility of lithium plating/stripping was dramatically improved.
(Invited) Prussian Blue Analogues Materials for Energy Storage Applications
Authors: Pasta Mauro
Published: February 2020

The open framework structure of Prussian Blue analogues (PBAs) is fundamentally different from other insertion electrode materials because of its large channels and interstices1. This structure is composed of a face-centered cubic framework of transition metal cations where each cation is octahedrally coordinated to hexacyanometallate groups. Large interstitial “A Sites” within the structure can accommodate zeolitic water and hydrated alkali ions (see Figure). This results in a general chemical formula of AxPR(CN)6nH2O, where A is an alkali cation such as K+or Na+, P is a transition metal cation and R(CN)6is a hexacyanometallate anion. Both the P-site transition metal cation and the R(CN)6
3-hexacyanometallate anion can be electrochemically active in this structure. The Prussian Blue framework structure has wide channels between the A sites, allowing rapid insertion and removal of not only alkali ions but also divalent and trivalent ions from aqueous solutions2. In addition, there is little lattice strain during cycling because the A sites are larger than the hydrated ions that are inserted and removed from them. The result is an extremely stable and rapid electrode: thousands of deep discharge cycles and high capacity retention at high C-rates were demonstrated in aqueous electrolytes3,4
,
5. When operated in organic, Na-ion electrolytes they show high specific capacities, long cycle life and good rate capability6. In my talk, I will show how these exciting properties are linked to the peculiar crystal structure of PBAs and how their chemistry can be easily tuned to adapt their electrochemistry to a variety of energy storage applications.

References

Hurlbutt, K., Wheeler, S., Capone, I. & Pasta, M. Prussian Blue Analogs as Battery Materials. Joule 2, 1950–1960 (2018).

Wang, R.Y. et al.Reversible Multivalent (Monovalent, Divalent, Trivalent) Ion Insertion in Open Framework Materials. Adv. Energy Mater.5, 1–10 (2015).

Pasta, M. et al.Manganese–cobalt hexacyanoferrate cathodes for sodium-ion batteries. J. Mater. Chem. A4, 4211–4223 (2016).

Pasta, M. et al.Full open-framework batteries for stationary energy storage. Nat. Commun.5, 3007 (2014).

Wheeler, S., Capone, I., Day, S., Tang, C. & Pasta, M. Low-Potential Prussian Blue Analogues for Sodium-Ion Batteries: Manganese Hexacyanochromate. Chem. Mater., article ASAP (2019).

Lee, H.W. et al.Manganese hexacyanomanganate open framework as a high-capacity positive electrode material for sodium-ion batteries. Nat. Commun.5, 5280 (2014).

Figure 1
Improving the Ionic Conductivity of Li15P4S16Cl3 By Doping
Authors: Liu Zhantao , He Xingfeng , Xiong Shan , Bai Jianming , Mo Yifei , Indris Sylvio , Chen Hailong
Published: February 2020

All-solid-state Li-ion batteries are a next generation electrochemical energy storage technology and an emerging alternative to conventional Li-ion batteries owing to higher energy density, wider operation temperature range and better safety properties1. Solid state ionic conductor as the solid electrolyte (SEs) is the key component in all-solid-state Li-ion batteries. Among existing SEs, sulfides SEs attract extensive attentions due to high room temperature ionic conductivity and favorable mechanical properties. However, currently known sulfide SEs only present a few limited types of crystal structures, which limits the materials design and hinders our understanding of ionic conduction mechanisms. Exploring new compound and new crystal structures beyond known groups is much desired in order to expand the ionic conductor database and advances the knowledge about ionic conduction.

Recently, our group successfully synthesized and identified a new lithium chloro-thiophosphate in Li2S-P2S5-LiCl system, namely Li15P4S16Cl3
2. This compound shows a low ionic conductivity of ~10-7 S/cm at room temperature. However, this crystal structure provides abundant choices for composition and unit cell size tuning, which may trigger high ionic conductivity. We successfully substituted P in Li15P4S16Cl3 with aliovalent cations to tune the Li content and the interstitial site occupancy. As a result, high room temperature conductivity of ~10-5 S/cm was achieved. The structure of the doped compounds was examined with using synchrotron X-ray and neutron diffractions. The Li+ diffusion pathway was also theoretically investigated with using ab initio molecular dynamics (AIMD) method and experimentally examined with using 7Li solid state nuclear magnetic resonance (NMR) techniques.

Auvergniot, J.; Cassel, A.; Ledeuil, J.-B.; Viallet, V.; Seznec, V.; Dedryvère, R., Interface Stability of Argyrodite Li6PS5Cl toward LiCoO2, LiNi1/3Co1/3Mn1/3O2, and LiMn2O4 in Bulk All-Solid-State Batteries. Chemistry of Materials
2017,
29 (9), 3883-3890.

Liu, ZT.; Zinkevich, T.; He, XF.; Indris, S.; Xiong, S.; Liu, J.; Xu, W.; Bai, J.; Mo, Yifei; Chen, HL., Li15P4S16Cl3, a new lithium chloro-thiophosphate as a solid state ionic conductor. Submitted.
(Invited) Interface Engineered Lithium Garnets for Lithium-Metal Batteries
Authors: Ramaswamy Murugan
Published: February 2020

Inorganic solid fast Li+ conductors based batteries are expected to overcome the limitations caused by the safety concerns of flammable organic electrolytes based Li+ batteries. Garnet structured solid electrolytes meet the requirements of being mechanically robust, display high ionic conductivities at room temperature, have large electrochemical window and more importantly few lithium garnets are electrochemically stable when in contact with metallic lithium [1]. However, all-solid-state Li metal batteries based on lithium garnet solid electrolytes have challenges in realizing high practical performances at room temperature due to their high electrode/electrolyte interfacial resistances, formation of reaction product layers at the interfaces and dendrite formation through the grain boundaries.

Onset of lithium dendrite within the electrolyte on repeated cycling at high current densities could be fatal for lithium metal batteries. Homogeneous current distributions at the Li-electrolyte interface along with the synthesis of highly dense solid electrolyte are significantly vital to ensure the safe usage. Hence, it is of utmost importance to provide a favorable contact between Li metal and lithium garnet electrolyte to reduce the interfacial resistance and remove inhomogeneous current distribution. The surface modifications at Li/solid electrolyte interface will be a useful technique to improve the cycle stability and rate capability of charge discharge reaction. However, negating interfacial resistance and the reaction product layer at the cathode-lithium garnet electrolyte interface is still a challenge.

The salient features of various strategies utilized to enhance the room temperature performance of Li metal battery based on garnet structured solid electrolyte will be discussed.

References

[1] R. Murugan, V. Thangadurai, W. Weppner, Fast lithium ion conduction in garnet typeLi7La3Zr2O12, Angew. Chem. Int. Ed. 46 (2007) 7778–7781.
Ab Initio Computation Design for Fast Ionic Conductors
Authors: Mo Yifei
Published: February 2020

Fast ionic conductor materials are the key component in enabling a variety of electrochemical devices. It is crucial to understand why only a few materials exhibit faster ionic conduction than typical solids and how one can design fast ion conductors following simple principles. Using ab initio modeling techniques, we studied a range of novel fast Li-ion conductor materials and identified the mechanisms leading to fast Li-ion conduction in solid materials. In lithium super-ionic conductors, we show that fast diffusion in super-ionic conductors happens through unique concerted migration mechanism of multiple ions with low energy barrier in contrast to isolated ion hopping in typical solids. We elucidate that low energy barriers of the concerted ionic diffusion are a result of unique mobile-ion configurations and strong mobile-ion interactions in these super-ionic conductor materials. Our theory provides a conceptually simple framework for guiding the design of super-ionic conductor materials. Using first principles computation, we demonstrate this strategy by designing a number of novel fast ion conducting materials. Furthermore, we highlight the design principles for having such crystal structures.

References:

Adelaide Nolan, Yizhou Zhu, Xingfeng He, Qiang Bai, Yifei Mo, “Computation-Accelerated Design of Materials and Interfaces for All-Solid-State Lithium-Ion Batteries”, Joule, 2, 2016-2046 (2018)

Xingfeng He, Yizhou Zhu, Yifei Mo, “Origin of Fast Ion Diffusion in Super-Ionic Conductors” Nature communications, 8, 15893 (2017)
Paradigms of Structural, Chemical, and Dynamical Frustration in Superionic Conductors
Authors: Wood Brandon C. , Kweon Kyoung , Varley Joel Basile , Shea Patrick , Adelstein Nicole
Published: February 2020

Rationally motivated computational discovery and optimization of solid electrolytes require the development of reliable descriptors for fast ionic conductivity. However, many of the fundamental motivations for superionic behavior in solids remain enigmatic, which has generally slowed progress in screening electrolyte candidates, as well as in tuning existing materials to maximize ionic conductivity. I will discuss our efforts using first-principles molecular dynamics simulations to unravel various mechanisms of ionic conductivity in model classes of solid electrolytes. Using computational “experiments”, our simulations systematically isolate factors such as stoichiometry, strain, composition, and crystal structure in the determination of ionic conductivity. Collectively, the results point to the importance of a frustrated energy landscape in promoting ultrafast diffusion. Different types of frustration in model superionic conductors will be discussed, arising from factors such as off-stoichiometry, competition between interstitial site occupancies, symmetry incompatibilities between local bonding character and lattice geometry, and dynamical frustration coupled to anharmonic processes. Physicochemical origins of the relevance of these factors for cation mobility will be explored, with a view towards developing design rules for engineering faster ionic conductors. Our findings suggest that the relative contributions of the different frustration paradigms depend chiefly on the fundamental nature of the lattice-forming ions, suggesting there may be no single universal descriptor for ionic conductivity, but rather classes of superionic conductors with similar underlying motivations. Specific examples will be drawn from our recent results on superionic materials based on oxides, halides, and polyatomic anions.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Particle Size and Morphology of Carbon Dioxide Reduction Electrocatalysts Fabricated By Pulse/Pulse-Reverse Electrodeposition
Authors: Skinn Brian , Leonard McLain Evan , Wang Dan , Brushett Fikile R. , Taylor E. J.
Published: February 2020

A variety of techniques for management of carbon dioxide emissions from power generation facilities and other industrial sites have been under active investigation for decades, in an effort to mitigate the environmental impacts of these releases. Once such approach is electrochemical reduction, which treats the waste CO2 as a source material for the production of value-added materials. Currently, the most promising form factor for this electrocatalytic application appears to be a stack-based system, where catalyst is immobilized on porous media that is interfaced with a liquid or solid electrolyte, and the reactant carbon dioxide is delivered to the active region by gaseous diffusion, which is orders of magnitude faster that diffusion though aqueous media. Various carbonaceous reduction products can be created depending on the composition, size, and microstructure of the catalyst particles, including formic acid/formate, carbon monoxide, alcohols, and hydrocarbons. In general, smaller catalyst particles, ideally in the nanoparticulate (« 1 μm) range, tend to yield superior catalytic performance, due to a combination of factors such as a higher density of exposed grain boundaries and a higher fraction of exposed crystalline facets that are uncommon in particles of micron size or larger.

This talk will survey recent work illustrating the ability of pulse/pulse-reverse electrodeposition processes to tune the size of particles applied to gas-diffusion electrode substrates, with a primary focus on two single-metal catalyst materials relevant to carbon dioxide electroreduction: tin and copper. The former is a catalyst primarily for formic acid production, while the latter is unique among single-metal catalysts as the only element known to date to produce significant amounts of hydrocarbons and/or alcohols. Particle morphology and representative particle size will be discussed as a function of pulsed electrodeposition waveform parameters, with the goal of highlighting overarching trends across the waveform space.
(Invited) Pulse Current Currents Transient Curve Study: Hydrogen Discharge and Modeling Attempts
Authors: Hihn Jean-Yves , Lain Amador Lucia , Rolet Jason , Doche Marie-Laure , Gigandet Marie-Pierre , Taborelli Mauro , Ferreira Leonel M.A. , Tardelli Joffrey , Bercot Patrice
Published: February 2020

Pulse currents and periodic reverse currents have proven to be of great interest for improving plating rate and coatings properties. Virtually all metals are sensitive to this technique. Pulse plating operates a periodically interrupted direct current. [1] Every short (usually a few milliseconds) cathodic pulse is followed by a short time-off, where no current is applied. Reverse plating implements an additional reverse current, periodically applied to the electrode [2]. Nevertheless, the optimum choice of the pulse current sequence parameters requires preliminary studies. Among them, the use of transient curves in response to pulse currents represents an interesting strategy. In the case of electrolytes with high Faradic yields, a succession of characteristic patterns may be observed. Particularly, two typical plateaus are noticeable, the first corresponds to the Faradic reduction of the metallic species involved below the diffusion limit, while the second, at higher potential, is attributed to the local resistance induced by the depletion of the concentration of the concentration of metal close to the interface. This situation called “diffusion limited range” interferes with the metal reduction, promoting the competitive hydrogen production. A recent work performed with copper during electroforming process show a large influence of the various steps on the hydrogen trapping into the coating [3]. On the contrary, electrolytes with low Faradic yields does not exhibit these two patterns, because the hydrogen discharge starts almost immediately with the current increase. In this case, reverse pulse is a possible solution to keep the possibility to modify the coating properties as for example the microstructure. In this case, the strategy for parameters determination is less obvious. In both situations, modeling constitutes a great help to seek for optimization.

[1] J. Cl. Puippe and N. Ibl, J. Appl. Electrochem., 10, (1980)

[2] E. J. Taylor, C. Zhou, and J. J. Sun, USPTO Patent Grants, (2005)

[3] L. Lain Amador, J Rolet, M-L Doche, P. Massuti-Ballester, M-P Gigandet, V. Moutarlier, M. Taborelli, L. M. A. Ferreira, P. Chiggiato, J-Y Hihn, ECS trans. ECS Transactions 85(13): 815-822 (2018)
The Properties of Pulse-Plated Copper Derived from Additive-Bearing, Low-Metal Ion Concentration Electrolytes
Authors: Pena Eden May Dela , Roy Sudipta
Published: February 2020

In semiconductor devices, copper metallization patterns are created using a combination of photolithography and electroplating. Photolithography, which uses light to transfer geometric patterns from a mask onto a substrate, is a multi-step process that is costly, time-consuming, and entails the use of harmful chemicals.

A recent electrodeposition process called Electrochemical nano and micro Fabrication by flow and Chemistry (EnFACE) was developed to enable single-step, direct, mask-less pattern transfers onto metallic substrates. EnFACE offers the possibility of replacing photolithography and avoid the difficulties associated with the process.

For typical copper electrolytes, the use of pulsed current and plating additives are known to improve deposit properties such as grain structure, mechanical strength, and throwing power. However, EnFACE uses an acid-free, additive-free, low-conductivity plating electrolyte containing low concentrations of metal salts (0.1 M CuSO4), a composition which significantly differs from the conventional copper plating electrolytes. Since the chemistry of this electrolyte is relatively new, a majority of its properties still needs to be discovered and understood. In this work, we report on the influence of current modulation (i.e., pulsed-current) on the properties of Cu electrodeposits obtained from additive-bearing, low metal salt concentration electrolyte.

Copper films were plated from 0.1 M CuSO4 electrolyte containing different concentrations of plating additives (i.e., 0%, 17%, 33%, 50%, 100%, and 200% of the industry recommended concentration) using direct (DC) and pulsed current (PC) modulations. The operating pulse parameters used were θ = 0.25 at a t
p of 100ms and the actual plating time was set for a deposit thickness of 25 um. The mechanical properties of deposits were characterised using the tensile test (UTM), while electrical properties were assessed using the four-point probe. Grain characteristics and morphology was investigated using scanning electron microscope (SEM), electron backscattered diffraction (EBSD), and X-ray diffraction (XRD).

Results of mechanical tests indicate that the PC-plated films possessed higher yield strength, tensile strength and ductility than its DC-plated counterparts (see Fig.1). Similarly, electrical measurements confirmed that pulse plated films have better conductivity than the DC plated ones. These changes in properties were traced to the changes in microstructure induced by the application of pulsed current modulation during plating. Finally, the use of pulsed current offers the added benefit of reducing the required amount of additives to obtain the desired deposit properties. The optimum additive concentration was 50% of the recommended value when using DC plating; while it was only 33% in PC plating.

Figure 1
Highly Active and Selective Electrochemical CO2 Reduction to Formate Enabled By Structural Defects on Converted Bi2O3 Nanotubes
Authors: Li Yanguang
Published: February 2020

Electrochemical CO2 reduction to fuels and commodity chemicals offers an attractive solution for energy and environmental sustainability. Formic acid (or formate) is suggested to be one of the most economically viable products. However, in order to realize its commercial viability, a drastic improvement of the electrocatalyst materials on both activity and selectivity is required. Here we report that structural defects have a profound positive impact on the electrocatalytic performance of Bi for selective CO2 reduction to formate. Bi2O3 double-walled nanotubes with fragmented outer surface are prepared as the template. They are cathodically converted to highly defective Bi nanotubes as evidenced by operando X-ray absorption spectroscopy measurements. This converted electrocatalyst enables CO2 reduction to formate with excellent activity, selectivity and stability. Importantly, its current density reaches ~288 mA cm-2 at -0.61 V versus reversible hydrogen electrode within a flow cell reactor under ambient conditions, which substantially exceeds the commercialization requirement. Using density functional theory calculations, the excellent activity and selectivity are rationalized as the outcome of abundant defective Bi sites that stabilize the *OCHO intermediate. Furthermore, this electrocatalyst is coupled with Si photocathodes and achieves high-performance photoelectrochemical CO2 reduction.
Tandem Catalytic Electro-Reduction of Carbon Dioxide into Ethylene at Industrial Scale
Authors: Wu Jingjie , Zhang Tianyu , She Xiaojie
Published: February 2020

The electrochemical reduction of CO2 into value-added multi-carbon products, for example C2H4, with efficiency and production rate at industrial level requires innovation of new catalyst concepts. Researchers have screened a wide range of metal-based materials for electrochemical reduction of CO2, and found only copper-based metals exhibit selectivity towards formation of hydrocarbons and oxygenates at fairly high efficiencies while silver and gold favor production of carbon monoxide (CO). In addition, recent studies have discovered that copper can catalyze CO electro-reduction at lower overpotentials, higher selectivity towards C2 products and higher production rate than CO2 electro-reduction. This phenomenon provides an opportunity to design cascade reaction through CO intermediate to improve the yield of C2 products from direct CO2 electro-reduction. Here we introduce the development of our tandem catalysis system involving both CO- and C2-selective catalysts to drive electro-reduction of CO2 into high order hydrocarbon products with a yield at industrial scale. The overall Faradaic efficiency of C2 products could be achieved up to 90% and the current density was reached over 1 A cm-2 at cathodic overpotentials of around -0.5 V. The cathodic CO2 electro-reduction can combine with anodic biomass valorization to offer more economic feasibility. Our study brings CO2 electro-reduction technology one step forward towards the industrial application.
Modeling of a Gas-Phase, Bipolar Membrane CO2 Electrolyzer
Authors: Star Andrew G. , Deutsch Todd G , Neyerlin K C
Published: February 2020

Aqueous electrochemical carbon dioxide reduction electrodes encounter prohibitive mass-transport limitations due to the low solubility of CO2 in aqueous electrolyte which limits cells to ~10 mA/cm2 reaction rates (1, 2). While C2+ products are desirable they remain economically challenging with low Faradaic efficiencies and high cell overpotentials (3). Alkaline environments are capable of facilitating preferential C-C bond formation (4); for example, the highest faradaic efficiencies for C2 products (5) and C3 products (6) have been reported under alkaline conditions. Unfortunately, carbon dioxide fouls alkaline reactors through the formation of carbonate species. Bipolar membrane-based CO2 electrolyzers, which combine gas phase acidic reduction and alkaline oxygen evolution, offer a unique opportunity to address the engineering and technological challenges of CO2 reduction. Such a system may preclude large anodic activation overpotentials while avoiding carbonate generation as the cathodic reaction proceeds in acid environment.

In the gas-phase bipolar membrane CO2 reduction reactor, fundamental questions remain regarding optimal choice of cell architecture, catalyst, and operating conditions. A model of the cell was developed and used to explore rate-limiting processes and process parameters effects on reaction kinetics which dictate Faradaic efficiencies and, therefore, economic viability of the reactor. Fundamental benefits and challenges of the reactor were assessed and contrasted with competing cell architectures in context of the ultimate parameter to be optimized, cost per kilogram of averted CO2.

R. Singh, E. L. Clark, and A. T. Bell, Phys. Chem. Chem. Phys., 17 (2015)

Higgins et al., ACS Energy Letters, 4 (1) (2018)

S. Bushuyev et al., Joule, 2 (2018)

Wang et al., ACS Catal., 8 (8) (2018)

Ma et al., J. Power Sources, 301 (2016)

Ren et al., J. Phys. Chem. Lett., 7 (2016)