bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesoscale Particle-Based Model of Colloidal Suspensions in Electric Fields
Authors: Giera Brian , Zepeda-Ruiz Luis , Pascall Andrew J. , Weisgraber Todd
Published: February 2020

We evaluate a particle-based model of colloidal suspensions that undergo electrophoretic motion[1] and deposition using an extensive set of mesoscale simulations that characterize experimentally relevant colloidal suspensions. We parameterize the model using only measurable quantities from suspensions that have properties of non-polar and aqueous solvents or ionic liquids with monodisperse polystyrene colloids between 1 nm - 1 μm in radius. The model accurately describes diffusive and electrophoretic motion of experimentally relevant colloidal suspensions. Furthermore, we extend the model to investigate electrophoretic deposition. The model is uniquely poised to elucidate how the deposit morphology depends on electric field strength, suspension properties, and colloid packing fraction because the model explicitly computes inter-particle interactions of colloidal suspensions.

[1] Giera, B.; Zepeda-Ruiz, L. A.; Pascall, A. J.; Kuntz, J. D.; Spadaccini, C. M.; Weisgraber, T. H. Mesoscale Particle-Based Model of Electrophoresis. Journal of the Electrochemical Society. The Electrochemical Society 2015, pp D3030–D3035.
Epd: From Order to Chaos By the LbL Modification of the Particle Surfaces
Authors: Gonzalez Zoilo , Filiatre Claudine , Castro Yolanda , Mendoza Carlos , Sanchez-Herencia Antonio Javier , Ferrari Begoña
Published: February 2020

Electrophoretic deposition (EPD) is a colloidal processing method which consists in the electrically driven movement and deposition of charged particles onto a conductive substrate. Understanding the colloidal behavior of nanoparticles is therefore mandatory to prepare stable and disperse suspensions suitable for EPD. Moreover, up today most of the proposed models for the EPD kinetics have been formulated considering the electrophoresis process. However, the effect of other parameters than electrophoresis over the kinetics, the deposition feature or the coating morphology, has been mainly empirically considered. In fact, in the well-known kinetics models based on the electrophoretic mobility of particles, these effects have been only quantified throughout the sticking factor, a probabilistic and empiric parameter.

A new perspective of the particles clustering can be extracted combining the modelling of interaction forces among particles, with the substrate coverage determined under laminar flow. In stable suspensions under similar electric conditions, changes in nature, length and ionization strength of surface modifiers determine the interaction forces among particles, resulting in an effective tool to manage particles flocculation and hence kinetics and ordering during the film growth. But also agglomerates fashioned by a Layer-by-Layer structure, built from the alternation of cationic and anionic polymers as modifiers of the particle surface, can contribute to tailor and intensify the deposition. The modification of the EPD kinetics induced by changes in the colloidal chemistry of the suspension of TiN nanoparticles and Ni(OH)2 nanoplatelets will illustrate mentioned phenomena.
(Special Invited Talk) The Lithium Battery Saga: From the Origin to the Future
Authors: Scrosati Bruno
Published: February 2020

After a brief excursus on the history of batteries, the development of lithium and lithium-ion batteries will be discussed with particular attention on their initial issues and the various directions followed to properly address them. The presentation will be then focused on the latest directions presently under way promoted by the rising concern on air pollution in large urban areas, as well as on the constantly increasing world’s temperature, which calls with urgency for a wide road distribution of sustainable vehicles, such as electric vehicles (EVs) and for a larger use of renewable energy source plants (REPs), which in turn has promoted large worldwide efforts to develop batteries suitable to operate as energy storage systems in REPs, as well as to power the electric engine. Clearly, these functions cannot be properly performed by lithium batteries (LIBs), namely the presently the power sources of choice for popular devices such as laptops, cellular phones and similar.
1
However, the present LIBs, based on intercalation chemistry, are not yet adequate for meeting the REP and EV requirements. In this respect, reduction in cost, as well as enhancement in safety, and particularly in energy density are required and this can only be achieved by totally renewing the battery chemistry, involving all three components, namely anode, cathode and electrolyte. Some approaches to reach  this goal  will be here presented and discussed. In particular it will be shown that, by exploiting adequate electrode nanoconfigurations, considerable progress may be obtained in the LIB technology
2,3
 Results in high-energy, lithium batteries, such as lithium-sulfur and, in particular lithium-air batteries
4,5 
will be also reported, in particular for discussing the most promising attempts to address the issues that still limit their practical development. The role of solid
6
and polymeric electrolytes
7
in enhancing the performance of the lithium batteries is evaluated. Some approaches towards the safe use of Li metal anode are also presented.  Finally, a brief discussion of the role of graphene in the lithium battery field , as well as the rising concern on the lithium world resources, will be included.8,9

References

Scrosati, B., Garche, J. , Journal of Power Sources 195:(2010) 241

Jung, H.G. , Hassoun, J., Park, J.-B., Sun, Y.-K. ,  Scrosati, B. , Nature Communications, 2 (2011) 516

Hassoun,J., Lee, K.-S, Sun, Y.-K., Scrosati, B., JACS 133 (2011) 3139

Jung, H.G. , Hassoun, J., Park, J.-B., Sun, Y.-K. ,  Scrosati, B. , Nature Chemistry,  4(2012) 579

Elia, G.A.,.Hassoun,J,,  Kwak, W.-J. , Sun,Y.-K.,  Scrosati, ,F.Mueller, F., .Bresser, D., Passerini, S. ,Oberhumer,P., Tsiouvaras, N.,  Reiter, J. , Nano Letters, 14(2014)6572

Agostini, M., Ahiara,Yamada, T.,:Scrosati, B, Hassoun, J. Solid State Ionics, 244 (2013) 48

Hassoun, J. ,Scrosati, B., Adv.
Materials, 22(2010) 5198 

Raccichini, R.,  Varzi, A., Passerini, S. Scrosati, B., Nature Materials, 14 (2015) 271

B. Scrosati, Nature, (2011) 473, 448
Electrochemical Behaviors of All-Phosphate Lithium-Ion Battery and All-Phosphate Solid-State Lithium-Ion Battery
Authors: Yu Shicheng , Tempel Hermann , Schierholz Roland , Aslanbas Özgür , Mertens Josef , de Haart L.G.J. , Kungl Hans , Eichel Rüdiger-Albrecht
Published: February 2020

Lithium-ion batteries are in focus of research around the world, due to their high volumetric and gravimetric energy density. For inorganic all-solid-state batteries since many years considerable effort has been devoted to the development of thin film batteries for their application in microelectronics [1, 2]. Recent research activities are directed to develop high capacity all solid state batteries for automobile applications (Toyota) [3, 4]. These kinds of applications of all-solid-state lithium-ion batteries require high cycling performance, high thermal stability, high capacity and high rate capacity.

The main objective of the current work is to build up an all-solid-state battery system which meets the previously listed. Electroactive phosphate materials with different microstructures were synthesized. Based on several combinations of materials, three phosphate compounds were synthesized and used as electrolyte and electrode materials, respectively. The carbon coated cathode (Li3V2(PO4)3/C) and anode (LiTi2(PO4)3/C) materials were first investigated in half-cells that use metallic lithium foil as counter electrode and reference electrode, 1 M LiPF6 in a 1:1 solvent mixture of ethylene carbonate (EC)/dimethyl carbonate (DMC) (LP30) was used as electrolyte. Afterwards, the selected electrode materials were used to make full cells by using LP30 liquid electrolyte. The working voltage, capacity as well as high-rate performance of the full cells were characterized. The optimum ratio of Li3V2(PO4)3/C and LiTi2(PO4)3/C in the full cell was investigated based on the electrochemical performances. Finally, an all-phosphate solid-state lithium-ion battery was made by using the electrode materials and Li1.3Al0.3Ti1.7(PO4)3 solid state electrolyte. The electrochemical behavior of the all-phosphate solid-state lithium-ion battery was investigated and compared with a full cell using liquid LP30 electrolyte. The working voltage of the Li3V2(PO4)3/C-LiTi2(PO4)3/C battery is in the range of 0.2-2.2V, which well matched with the electrochemical window of the solid electrolyte Li1.3Al0.3Ti1.7(PO4)3. Applying materials with high Li-ion conductivities such as Li3V2(PO4)3 and LiTi2(PO4)3provides the advantage of high rate capability for all solid state batteries.

Reference

   [1]  M. Koo, K. Park, S. H. Lee, M. S. Duh, D. Y. Jeon, J. W. Choi, K. Kang and K. J. Lee, Nano Lett., 2012, 12, 4810–4816.

   [2]  Y. J. Nam, S. J. Cho, D. Y. Oh, J. M. Lim, S. Y. Kim, J. H. Song, Y. G. Lee, S. Y. Lee and Y. S. Jung, Nano Lett., 2015, 15, 3317–3323.

   [3]  M. S. Beal, B. E. Hayden, T. L. Gall, C. E. Lee, X. Lu, M. Mirsaneh, C. Mormiche, D. Pasero, D. C. A. Smith, A. Weld, C. Yada and S. Yokoishi, ACS Comb. Sci., 2011, 13, 375–381.

   [4]  C. Yada, C. E. Lee, D. Laughman, L. Hannah, H. Iba and B. E. Hayden, J. Electrochem. Soc., 2015, 162, A722–A726.
NaFe1-xMnxPO4 (0≤x≤1) as Positive Electrode Materials for Na-ion Batteries
Authors: Giner Morgane , Galceran Montse , Reynaud Marine , Saurel Damien , Casas-Cabanas Montse , Rojo Teófilo
Published: February 2020

Recent progress in the development of sodium insertion materials for Na-ion batteries show that they can be considered as interesting alternative to Li-ion batteries owing to more abundant and widespread sodium resources and lower cost as compared to lithium [1,2].

Olivine transition metal phosphates isostructural to the well-known LiFePO4are good positives electrode candidates for Na-ion batteries. Indeed, it has been shown that 1 Na per formula unit can be reversibly deintercalated from olivine NaFePO4 at a potential of 2.8 V vs. Na/Na+ delivering a theoretical capacity of 154 mAh/g [3,4]. However, materials working at higher voltage and with higher cycling potential are highly desirable to increase the energy density. Following this approach, mixed Na[Fe,Mn]PO4compositions with olivine structure are very promising[5].

In this work, we describe the synthesis and characterisation of the solid solution NaMnxFe1-xPO4 (0≤x≤1) prepared from their lithium counterparts (LiMnxFe1-xPO4). We have analysed the structural evolution of these materials with varying Mn content and the electrochemical properties of carbon coated NaMnxFe1-xPO4(0≤x≤1) phosphate materials have been characterized in Na half-cells by galvanostatic cycling under various conditions. The results obtained will be here presented and discussed in terms of energy density and efficiency.

[1]B. L. Ellis, W. R. M. Makahnouk, Y. Makimura, K. Toghill and L. F. Nazar, Nat. Mater. (2007), 6, 749.

[2]V. Palomares, P. Serras, I. Villaluenga, K. B. Hueso, J. Carretero-Gonzalez and T. Rojo, Energy Environ. Sci., (2012), 5, 5884.

[3] P. Moreau, D. Guyomard, J. Gaubicher, F. Boucher. Chem Mater. (2010), 22, 4126-4128.

[4] M. Casas-Cabanas, V. Roddatis, D. Saurel, P. Kubiak, J. Carretero-Gonzalez, V. Palomares, P. Serras and T. Rojo, J. Mater. Chem. (2012), 22, 17421.

[5] K. T. Lee, T. N. Ramesh, F. Nan, G. Botton, L. F. Nazar. Chem. Mater. (2011), 23, 3593-3600.
Novel Electrode Materials for Rechargeable Magnesium Ion Batteries
Authors: Wang Lu , Vullum-Bruer Fride
Published: February 2020

Over the past few years, considerable effort has been devoted to the development of new energy storage devices with high power and energy density to substitute Lithium-based batteries, because the predicted high demand associated with many large-scale applications has generated serious concerns regarding the safety and sustainability of metallic Li.[1] In particular, Mg ion battery (MIB) has been regarded as the most promising candidate because of its ‘green’ character, high natural abundance in the Earth’s crust (13.9% as compared to 7*10-4 % for Li), and chemical stability.[2] In comparison with Li, Mg is inherently much safer due to its air stable and free of dendritic formation during electrochemical cycling,[3] the latter feature could enable Mg has a theoretical volumetric capacity of 3833 mAh/cm3, nearly twice as that of Li, 2061 mAh/cm3, indicating the good potential of MIB to reach a high volumetric energy density.[4,5] However, it is still in high demand to find the electrode materials that unites with metallic Mg and fulfills requirements such as high specific capacity, power density, rate performance and good recyclability.[2,6,7]

Here, we report two novel electrode materials, Mn3O4 nanoparticles with high specific surface area (102.4 m2/g) and graphene nanosheets. The studies of Mg-battery performances were carried out in a standard coin cell which the synthesized materials as cathode (or anode), magnesium ribbon as anode (or cathode), glass fiber as separator and (PhMgCl)2-AlCl3/THF as electrolyte. The electrochemical performance was evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge techniques.

References:

[1] L. G. Lu, X. B. Han, J. Q. Li, J. F. Hua and M. G. Ouyang, J. Power Sources, 2013, 226, 272.

[2] E. Levi, Y .Gofer and D. Aurbach, Chem. Mater., 2010, 22, 860.

[3] J. O. Besenhard and M. Winter, ChemPhysChem, 2002, 3, 155.

[4] M. Matsui, J. Power Sources, 2011, 196, 7048.

[5] C. Ling, D. Banerjee and M. Matsui, Electrochim. Acta, 2012, 76, 270.

[6] H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour and D. Aurbach, Energy Environ. Sci., 2013, 6, 2265.

[7] I. Shterenberg, M. Salama, Y. Gofer, E. Levi and D. Aurbach, MRS Bull., 2014, 39, 453.
High-Rate Sodium Storage in Anatase Mesoporous TiO2 Nanoparticles Embedded in Carbon Nanotubes
Authors: Hwang Jang-Yeon , Myung Seung-Taek , Abouimrane Ali , Belharouak Ilias , Sun Yang-Kook
Published: February 2020

Since sodium is substantially less expensive and more abundant than lithium, sodium-ion batteries (SIBs) are considered a desirable alternative to lithium-ion batteries. As for anode side, conversion and alloy electrode materials are attractive because of their high capacity when reacting with sodium ions, even at high rates. However, the deposition of metallic Na on the anode surface is an issue, which, in turn, jeopardizes the safety of the battery. Recently, several metal oxides have been introduced as anodes for SIBs, such as anatase TiO2, TiO2(B), Li4Ti5O12. The main disadvantage of using transition metal oxides for Na+-ion batteries is the sluggish kinetics of insertion of Na+ ions into the structure. Here, we introduce nanosized anatase TiO2 that is partially doped with fluorine (TiO2-
dFd) to form electro-conducting trivalent Ti3+ as an ultrafast Na+ insertion material for use as an anode for sodium-ion batteries. In addition, the F-doped TiO2-
dFd is modified by electro-conducting carbon nanotubes (CNTs) to further enhance the electric conductivity. The first discharge capacity of the F-doped TiO2 embedded in CNTs is approximately 250 mAh (g-oxide)-1, and is retained at 97% after 100 cycles. As expected, a high-rate performance was achieved even at the 100 C discharging rate (25 A g-1) where the composite material demonstrated a capacity of 118 mAh g-1 under the 0.1C-rate charge condition
Surface Reactivity of a Carbonaceous Cathode in Li-O2 CELLS
Authors: Brutti Sergio , Carboni Marco , Marrani Andrea Giacomo
Published: February 2020

Li-O2 batteries are currently one of the most advanced and challenging electrochemical systems with the potential to largely overcome the performances of any existing technology for energy storage and conversion. However, these optimistic expectations are frustrated by the still inadequate understanding of the fundaments of the electrochemical/chemical reactions occurring at the cathode side, as well as within the electrolyte and at the three-phase interface. In this work, we studied the evolution of the morphology and composition of a carbonaceous cathode in the first discharge/charge in a Li-O2 cell with LiCF3SO3/TEGDME electrolyte by X-ray photoemission spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. Experiments have been carried out ex situ on electrodes recuperated from electrochemical cells stopped at various stages of galvanostatic discharge and charge. Apparently, a reversible accumulation and decomposition of organic and inorganic precipitates occurs upon discharge and charge, respectively. These precipitations and decompositions are likely driven by electrochemical and chemical parasitic processes due to the reactivity of the cathode carbonaceous matrix.
Fabrication of Nano-Rod Structures By Cu Galvanic Displacement Reaction on Fe-Ni-Co Nanowires
Authors: Geng Xiaohua , Podlaha Elizabeth J
Published: February 2020

Introduction

The use of nanoscale, nanowires in microfluidic devices and sensors require the tip size to be of the order of molecules to be detected, while integrating them to micro and macro-scale connectors. The work presented here creates multiscale wires through galvanic displacement and subsequent etching techniques. Nanosized, rod-like structures were generated from electrodeposited Fe-Ni-Co nanowires, followed by displacement of a part of the Fe-Ni-Co by Cu. A second Fe-Ni-Co layer was then deposited onto the Cu layer.  Once the wires are released, a part of the Cu was selectively etched.

Experimental

Then Fe-Ni-Co nanowires were fabricated with a pulsed current electrodeposition method, 2 s on/2 s off1, in a polycarbonate membrane having pores of ~100 nm, from a boric acid-sulfate-sulfamate electrolyte. Displacement was carried out in a copper citrate solution and the etching step was completed in a citrate-boric acid electrolyte. The pH of the copper displacement solution was a variable. A commercial gold displacement solution was used to coat the resulting nanowire. A rotating cylinder electrode cell design was also used to characterize the deposition and displacement reactions. The resulting structure was characterized with Field Emission Scanning Electron Microscope (FESEM) and High-resolution transmission electron microscopy (HRTEM).

Results and Discussion

FESEM and TEM results indicate that rod-like regions occurred between two supporting Fe-Ni-Co regions in the nanowires (Figure 1), with the diameter of the rods on the order of 10 nm. Inner-rods was formed at low pH (pH=0, 1) however gaps were generated at high pH (pH=4). A complexation model predicted different Cu(II) species that govern the displacement reaction at low and high pH. SEM-EDS analysis show that there is indeed Fe and Ni remaining in the rod-like region. The results suggest that the copper ions are penetrating into the template and around the Fe-Ni-Co nanowires. A thin (~5 nm) Au layer was successfully coated on the rod-like nanowires.  

Conclusion

A new multistep method was developed to create nanowires with smaller, inner rod regions via electrodeposition, galvanic displacement and etching. The displacement reaction was affected by pH attributed to the type of complex Cu-citrate species. The resulting structure was then uniformly coated with gold by displacement.

Acknowledgement

The authors acknowledge and thank Roche Diagnostics for support of this project.

Reference

H. Kim, S.  A. Soper, E. J. Podlaha, ECS Trans.
53, 9 (2013).

Figure 1
Morphology and Electrical Properties of Copper Thin Films Electroplated on Ni/n+-Si(100) for Silicon Solar Contact
Authors: Mebarki Mourad , Moussi Abderrahmane , Azizi Amor , Khelladi Mohamed redha , Mahiou Linda
Published: February 2020

Cu thin films were electrodeposited on Ni/n+-Si(100) substrate from sulfuric solution with fixed pH at room temperature. The effect of deposition time of Cu coatings was studied by using the chronoamperometry method (CA), the atomic force microscopy (AFM), X-ray diffraction (XRD) and four- point probe to investigate surface topography , structure and electrical properties of Cu films. From electrochemical measurements, the Cu film thickness ranging from 63 nm to 8.9 µm was calculated using Faraday’s law. The AFM study showed a rugose surface of the Cu films and the variation of film morphology with deposition time were established. The XRD spectra revealed the formation of thin Cu films with a preferential orientation.  Sheet resistance and resistivity showed strong dependence on the deposition time of Cu films. Cu films being the future metal contact for silicon solar cells.

Keywords: Cu , Electrodeposition , Morphology , Structure , Thin films , resistivity.

Figure 1
Effects of Organic Additives on Formation of Copper Pillar during Electroplating Process
Authors: Lee Yu-Jin , Lee Woon-Young , Lee Dong-Ryul , Jin Sang-Hoon , Lee Min-Hyung
Published: February 2020

Cu electroplating process has been extensively used in the fabrication of on-chip interconnects such as Cu pillar, TSV, micro-bump of microelectronic devices for their further integration [1]. In general, the process is performed in a acid plating bath made up of inorganic components (copper sulfate, chloride ion, and sulfuric acid) and organic additives including suppressor, accelerator, and leveler. The organic additives play very critical roles in changing the shape, uniformity of deposits [2]. In the case of Cu pillar for flip chip packaging, a flat surface on the top of Cu pillar is required for implementation of the stacking materials like Sn-Ag solder [3].

In this study, Cu pillar with flat surface was successfully electroplated onto photoresist(PR) patterned Si wafer by controlling composition of the three organic additives. In order to understand the correlation between characteristics of additives (functional group, molar mass, N density and so on) and deposits,  electrochemical behavior, PR reactivity and shape of Cu pillar have been investigated by galvanostatic potential transient measurements, contact angle measurement and scanning electron microscopy, respectively. As a result of the investigation, we will identify effects of the additives on formation of Cu pillar during electroplating process, and apply electroplating technology to many part of electronic devices from wide pillar to fine-pitch micro-bump.

Fig. 1. SEM images of (a) cross-section view and (b) tilted view of Cu pillar (100 um in diameter and 40um in height) and (c) chronopotentiometry graph (inner image: confocal laser scanning microscopic graph and OM image of top view)

[1] P.C. Andricacos, The Electrochemical Society Interface, spring (1999) 32-37.

[2] W.C. Chen, T.T. Huang, C.H. Lai, S.W. Chou, C.H. Shih, ECS Transactions, 52 (2013) 453-460.

[3] S. Chung, E. Kuo, M. Tseng, IMPACT 2009. 4th International. IEEE, (2009) 432-435.

Figure 1
The Role of Electrolyte Composition on Codeposited Ag and Cu
Authors: Karakaya Ishak , Ulu Fulya , Demirci Gökhan , Erdogan Metehan
Published: February 2020

The eutectic Ag-Cu composition is a common brazing alloy. A complex ion bath containing KAg(CN)2, CuCN, KCN and K4P2O7 was used to codeposit Ag and Cu. The effects of KAg(CN)2, KCN and K4P2O7 concentrations on the composition and morphology of electrodeposited Ag-Cu films was investigated in this study. A constant CuCN concentration of 0.1 M was used. The increase in KCN and KAg(CN)2 concentrations caused major increases in Ag contents, but increase in K4P2O7 concentration caused a minor decrease in Ag content of the film. The results are summarized in the figure. The deposits were found to be globular clusters when high KAg(CN)2 concentrations were used. Finer microstructures and higher Ag contents were obseerved in deposits produced in electrolytes containing higher KCN concentrations.

Figure 1
Analysis of a Hydrogen Pump Driven Refrigeration Cycle
Authors: Darling Robert M.
Published: February 2020

Hydrogen oxidation and reduction are fast reactions in polymer-electrolyte cells with modest amounts of noble metal catalyst.  Hydrogen can be pumped and compressed in a cell that oxidizes hydrogen at the anode at low pressure and reduces protons at high pressure at the cathode.  A typical hydrogen cell resembles a polymer-electrolyte fuel cell or electrolyzer with gas-diffusion electrodes containing platinum or a platinum alloy catalyst surrounding a polymer-electrolyte membrane like Nafion.  Hydrogen pumps can be more efficient and durable than mechanical compressors. 

Conventional polymer-electrolyte membranes like Nafion need to be moist in order to have high ionic conductivity.  This water is a nuisance in most applications; however one exception is a refrigeration cycle.  The thermodynamics of a refrigeration cycle with water as the working fluid driven by an electrochemical hydrogen pump is studied in this work.  In particular, an expression for the work done by the reactor is derived that includes terms associated with the partial pressure changes of hydrogen and water and irreversible losses.

The coefficient-of-performance (COP) of the hydrogen-pump system approaches the Carnot limit when the mole fraction of hydrogen entering the reactor is small (< 0.01).  Unfortunately, the amount of water crossing the membrane under these conditions far exceeds what can be supplied by osmotic drag.  The calculated COP at a hydrogen mole fraction of 0.1 is approximately half of the Carnot limit, a promising result, when the hot and cold reservoirs are at 40oC and 20oC.  Unfortunately, replacing a mechanical compressor with a hydrogen pump does not address the main issue with using water as refrigerant which is low total gas pressure.  Water has low vapor pressures at typical hot and cold reservoir temperatures.  Therefore, the electrochemical reactor would need to operate under vacuum and be designed to simultaneously provide low pressure drop and high mass transport rates.
Black Liquor Electrolysis for Hydrogen and Lignin Extraction
Authors: Oliveira Raisa Costa Paes , Mateus Maria , Santos Diogo M.F.
Published: February 2020

Black liquor is a pulp mill effluent from wood cooking and has a solid content of 15-18% (weak black liquor), which is mostly lignin, an organic compound that finds wide applications in the market. Black liquor is currently used for steam generation purposes, by burning it, which is not an efficient process due to the undifferentiated combustion of the liquor, losing most of the lignin potential. Considering the world’s energy picture, it is essential to develop sustainable energy generation alternatives, including through waste recovery.

Having this in mind, the current work focuses on the electrolysis of black liquor for energy recovery. The process has several economic and environmental advantages, as it simultaneously generates a clean fuel (hydrogen) at the cathode and a precipitated material with economic value (lignin) at the anode surface [1]. The generated hydrogen can be eventually fed to a fuel cell that partially powers the electrolysis plant, thereby decreasing the electricity costs.

Herein, platinum (Pt), nickel (Ni), and AISI 304 stainless steel bulk electrodes are tested for black liquor electrolysis, both as anodes and as cathodes. Voltammetric methods are used to study the lignin anodic oxidation at the Pt, Ni and AISI 304 electrodes at temperatures ranging from 25 to 55 ºC. Kinetic and diffusional parameters are calculated (e.g., charge transfer and diffusion coefficients, number of exchanged electrons). The hydrogen evolution reaction in the black liquor is also evaluated at the same electrodes, with Pt and Ni showing the best performance. Activation energies are calculated for both electrochemical processes.

Finally, a small-scale laboratory black liquor electrolyzer using Ni plates, both for anode and for cathode, is assembled and its operation parameters are evaluated, specifically the applied cell voltage and the electrolysis duration. The produced lignin is characterized by MIR and reveals a high purity compared with typical lyophilized and Klason lignin.

[1] H.R. Ghatak, S. Kumar, P.P. Kundu, Int. J. Hydrogen Energy 33 (2008) 2904-2911.
Cobalt-Free Mixed Conducting Ba0.95La0.05FeO3-δ Thin Films As Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells
Authors: Ciucci Francesco
Published: February 2020

Solid oxide fuel cells (SOFCs) are devices that can convert chemical energy to electricity directly with high efficiency and fuel flexibility. Here, we fabricate perovskite single crystal thin films as cathodes with the composition of Ba0.95La 0.05FeO3-δ (BLF) by pulsed laser deposition (PLD) on yttria-stabilized zirconia (YSZ) substrates. Sm-doped Ceria (SDC) is deposited between YSZ and perovskite thin films in this study as an interlayer. The phase structure, surface morphology and roughness of the BLF thin films are characterized by X-ray diffraction and atomic force microscopy. X-ray photoelectron spectroscopy is used to analyze the elemental composition and chemical state of the deposited thin film [1-2]. Electrochemical impedance spectra measurements obtained from the symmetric cells with the configuration of BLF /SDC/YSZ/SDC/ BLF reveal that polarization resistance of BLF (001) thin films (100 nm) is as low as ~0.1 Ω cm2 at 700 °C and 0.21 atm oxygen pressure. The polarization resistances of BLF are lower than those of other perovskite electrodes, e.g., La0.6Sr0.4Co0.8Fe0.2O3-δ. Furthermore, our computational results, including density functional theory and molecular dynamics simulations, show that the BLF is characterized by low vacancy formation energy and fast oxygen transport [3-4].

References: 

[1] D. Chen, C. Chen, F. Dong, Z. Shao, F. Ciucci, J. Power Sources, 250, 188-195 (2014)

[2] C. Chen, D. Chen, Y. Gao, Z. Shao, & F. Ciucci. J. Materials Chemistry A, 2, 14154-14163 (2014) 

[3] Z.M. Baiyee, C. Chen, & F. Ciucci. Physical Chemistry Chemical Physics, 17, 23511-23520 (2015)

[4] C. Chen, Z.M. Baiyee, & F. Ciucci. Physical Chemistry Chemical Physics, 17, 24011-24019 (2015)
The Cathodic Behavior of Doped Pr2NiO4 Cathode for Solid Oxide Fuel Cell with Lsgm As Electrolyte
Authors: Xie Jing , Ban Shuai , Zhou Hongjun , Ishihara Tatsumi
Published: February 2020

Solid oxide fuel cells (SOFCs) is now expectative as its highly efficient and the environmental friendly electric power generator for the next generation and now expectative for its application to the stationary field, such as power plants and home electricity-heat simultaneous generating systems, because of its high operating temperature and the flexibility of fuels. Unfortunately, cathode properties will drop seriously as the operating temperature decreases. One of the main subjects to overcome this problem is the development of novel cathode materials with high electrical conductivity and stability in the SOFC operating conditions. As reported, Pr2Ni0.71Cu0.24Ga0.05O4(PNCG) showed very good oxygen diffusivity, lower polarization resistance [1~3] and appropriate thermal expansion coefficient [4]. Therefore PNCG is a good candidate for IT-SOFC.

In the present study, various oxides were prepared by using the conventional solid-state reaction methods. XRD was employed to check the crystal structure of the products. The cell tested consists of PNCG cathode, La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte and Ni-Fe bimetallic anode. For measuring power generating properties, pure O2 and humidified H2were used for oxidant and fuel, respectively. The temperature range is 773 K~1073 K, normal pressure, and 100 cc/min gas flow rate. The impedance spectra were measured to study the oxygen diffusivity and oxygen reduction reaction at cathode.

The XRD results indicate that the PNCG was obtained with K2NiO4 structure, no other oxides were found. When the cell voltage was 0.7 V, the cell power density was 484.2 mW/cm2 at 1073 K, 239.2 mW/cm2 at 973 K, 52.5 mW/cm2 at 873 K and 6.7 mW/cm2at 773 K, respectively. The cell with PNCG cathode exhibited reasonable cell performances among the operating temperature range. Figure 1 shows the power generation property of the cell using PNCG cathode.

The impedance spectra were measured too. The result was shown in figure 2. The impedance spectra were fitted with Zview software. Then theoretical calculation using the Adler-Lane-Steel and Dusty gas models were employed to analyze the oxygen diffusion and oxygen reduction reaction on PNCG.

Consequently, this study reveals that PNCG does function on improving catalytic property of cathode materials for its high surface exchange coefficient and oxygen diffusion coefficient. PNCG is a good candidate cathode for SOFC.

References

[1] X. Meng et al. Ceramics International B 41, (2015):  12107-12114

[2] J. Hyodo et al. Solid State Ionics 262, (2014): 889-892

[3] J. Hyodo et al. Solid State Ionics 220, (2013): 16-20

[4] J. Xie et al. Journal of Power Sources, 228, (2013): 229-236

 

Figure 1
High Temperature Electrical Properties of Barium Zirconate-Cerate Type Proton-Conducting Ceramics
Authors: Shimada Hiroyuki , Yamaguchi Toshiaki , Sumi Hirofumi , Fujishiro Yoshinobu
Published: February 2020

We have investigated electrochemical ceramic cells such as fuel cells and electrolysis cells using perovskite-type proton-conducting ceramics for electrolyte material. In particular, we focus on Barium zirconate-cerate (Ba(ZrCe)O3) type proton-conducting ceramics, which have high protonic conductivity and chemical stability. Many researchers have used these materials for proton-conducting solid oxide fuel cells (SOFCs) and have reported good performance. We have also obtained similar good performance in electrochemical measurements using anode-supported SOFCs. However, the bulk conductivity of Ba(ZrCe)O3 showed a significant change around 700°C. In this study, we discussed the change in the conductivity related to the transport number and the thermal expansion behaviors.
Synthesis and Characterization of Oxygen Evolution Reaction(OER) Catalysts for Anion Exchange Membrane Electrolyzer
Authors: Lee Kyu Hwan , Choi Sung Mook , Jang Myeong-Je
Published: February 2020

Hydrogen has recognized as a high energy density, efficient, and environmentally clean in a variety of renewable energy sources can be produced by an anion exchange membrane electrolyzer that has several advantages as use of non-precious metal oxide catalysts, high pressure operation, and high efficiency compared with other type electrolyzers.

The target of this study is the development of non-precious catalysts with high activity via simple and efficient synthesis method. The prepared OER electrocatalysts were characterized by various physicochemical analyses such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, to investigate electrocatalytic properties of prepared catalysts, we carried out electrooxidation activity measurements such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), long-term stability test, and electrochemical impedance spectroscopy (EIS). The synthesized CuCoO4 series catalysts show a different tendency in physicochemical properties and OER activity with synthesis conditions as pH, heat treatment temperature, and drying method.

Figure 1
Preliminary Study of a Hydrogen-Vanadium Flow Battery
Authors: Dowd Regis Paul , Ying Andrew , Nguyen Trung Van
Published: February 2020

Hydrogen-vanadium flow batteries offer a feasible solution for storing electrical energy from the grid or directly from renewable energy sources such as wind and solar. While charging, a hydrogen-vanadium flow battery stores energy in the form of hydrogen and vanadium (V). During discharge, hydrogen is consumed at the negative electrode and vanadium (V) is reduced to vanadium (IV) at the positive electrode. Vanadium systems demonstrate no issues with membrane fouling or metal dendrite formation.1 Additionally, vanadium solutions have low volatility, low corrosivity, and do not produce toxic vapors.1 Due to the relatively high cost of vanadium, the hydrogen-vanadium flow battery is attractive over the all-vanadium system due to the 50% reduction in the amount of vanadium solution required. Past research by Yufit et. al. has shown the feasibility of the hydrogen-vanadium flow battery and the importance of vanadium electrode wettability on fuel cell performance.1 Additionally, studies by Menictas et. al. also revealed crossover of vanadium species during operation of the vanadium-oxygen flow battery, sparking our interest in vanadium’s effect on the hydrogen electrode catalyst.2

In this study, we examine the performance of a hydrogen-vanadium flow battery when using interdigitated flow fields at both electrodes and a high surface area carbon nanotube electrode as the vanadium electrode. With a reference electrode placed in the vanadium side, we separate the cell performance into individual electrode performance.  Using the half-cell results and electrochemical impedance measurements we identify the components and processes that have the greatest influence on the performance of the flow cell during discharge and charge.  Additionally, we explore if crossover of vanadium through the polymer electrolyte membrane results in any negative effect on the platinum catalyst at the hydrogen electrode. This will be determined by employing electrochemical measurement techniques using a platinum rotating disc electrode and a 3-electrode arrangement. In turn, the effect of vanadium crossover to the hydrogen electrode will be investigated by measuring effective exchange current density and electrochemical active surface area (ECSA) of platinum when vanadium (IV) and vanadium (V) are present in the electrolyte.

References:

V. Yufit, B. Hale, M. Matian, P. Mazur and N. Brandon, “Development of Regenerative Hydrogen-Vanadium Fuel Cell for Energy Storage Applications,” Journal of the Electrochemical Society, 160(6), A856-A861 (2013).

C. Menictas and M. Skyllas-Kazacos, “Performance of vanadium-oxygen redox fuel cell,” Journal of Applied Electrochemistry,  41, 1223-1232 (2011).
(Invited) Revealing the Optimum Li-Mobility in Garnet Electrolytes
Authors: Brugge Rowena , Chater Richard John , Manalastas William Wang , Kilner John A. , Aguadero Ainara
Published: February 2020

“Li-stuffed” garnet electrolytes can deliver the adequate Li-conductivity, safety and cycle life required for the commercialisation of high-energy density batteries (i.e. high voltage Li-ion and Li-metal based batteries). However, these garnet electrolytes, if they are not processed properly, suffer from severe moisture-sensitivity that leads to drastic
degradation of their transport and microstructural properties – a problem that has not been universally recognised in the field and that is impeding the achievement of the optimum performance of garnet electrolytes in Li-batteries. This is partially due to the Li-H Exchange taking place during the atmospheric degradation process that not only leads to a decrease in the Li transport number but also to the formation of insulating secondary phases (i.e. Li2CO3, LiOH) in the grain boundaries and interfaces. In fact, the integration of garnet electrolytes in Li battery devices has been delayed due to the high interfacial resistances at the lithium metal anode side which limits the performance to low current density cycling[1]. Again, this high interfacial resistance has been related to the formation of a Li2CO3 layer between the garnet and the Li-metal when not enough care is taken with the control of moisture during processing of the ceramics[2].

  We have developed a unique setup that allows a strict control of the moisture during the processing and characterization of the garnets. The synthesis and processing of Li7-nxAx(n-1)xLa3Zr2O12 (A= Ga(III), Ge(IV), = lithium vacancy, VLiꞌ) garnets have been performed in a Ar-filled glove box with a high temperature furnace coupled to it.  This has result in a three-fold enhancement in the total lithium-ion conductivity, up to 1.3 mS/cm at 24
°
C[3] and the performance of garnets with highly controlled microstructure with densities up to 98%. The intrinsic Li-mobility in garnets has been characterised by means of impedance spectroscopy and 6Li-isotopic labelling. The effect of the moisture-degradation on the charge carriers concentration and mobilities has also been analysed using a controlled exchange in D2O. To achieve this, a focussed-ion beam, secondary ion spectrometer has been used to detect all elements and their isotopes and yields the distribution of species in three dimensions on a nanoscale resolution, allowing the evaluation of the independent contributions of each isotope (6Li+, 7Li+, H+, D+) to the conduction process.

[1] S. Ohta, et al., J. Power Sources, 2013, 238, 53

[2] L. Cheng, et al., PCCP, 2014, 16, 18294

[3] C. Bernuy-Lopez, et al. Chem. Mater., 2014, 26, 3610
Exploring the Critical Role of Binders for Silicon Electrodes in Lithium-Ion Batteries
Authors: Xu Jiagang , Wang Yikai , Cheng Yang-Tse
Published: February 2020

The commercialization of high capacity silicon (3579 mAh g-1, based on Li15Si4) is limited by the large volume change of silicon during lithiation and de-lithiation, resulting in poor cycling performance. The choice of polymeric binders is critical to the electrochemical performance of silicon based electrodes. It is known that the cyclability of silicon electrodes can be much enhanced when using carboxymethyl cellulose (CMC), sodium alginate, Nafion as binders, instead of the conventional polyvinylidene fluoride (PVDF) binder. This work focuses on a comprehensive study of the binding mechanisms of these binders for silicon electrodes. Instrumented nanoindentation is used to measure Young’s modulus, hardness, and viscoelastic behavior of these polymeric binders when the binders are either dry or immersed in the organic electrolyte. Together with characterization tools, such as Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), the role of the mechanical behavior of binders and the interaction between polymeric binders and silicon will be reported.
(Invited) The Role of Ionic Transport in Nuclear Waste Immobilization and Membrane Separations
Authors: Brinkman Kyle S
Published: February 2020

Durable ceramic waste forms that incorporate a wide range of radionuclides have the potential to broaden the available disposal options and to lower the storage and disposal costs associated with advanced nuclear fuel cycles.  Ceramic waste forms have also been studied because of their superior chemical durability and the ability to incorporate a broad spectrum of chemical species within the lattices. Recent work has shown that they can be produced from a melting and crystallization process similar to melter technology currently in use for High Level Waste (HLW) vitrification in several countries around the world.   Cesium (primarily Cs137) is one of the more problematic fission product radionuclides to immobilize because of its volatility at high temperature and its tendency to form water-soluble compounds.  Hollandite oxides of the form BaxCsyGa2x+yTi8-2x-yO16 (x=1.33, 1.04, 0.667, 0; y=0, 0.24, 0.667, 1.33), similar to materials used as Li battery cathodes are currently under evaluation for the immobilization of Cs.  The phase formation, experimentally determined ionic conductivity, and propensity for elemental release were determined for substituted hollandites containing different levels of Cs. Implications for controlling the ionic transport in diverse applications of ceramic-ceramic composites ranging from mixed ionic and electronic conducting separation membranes to nuclear waste immobilization will be discussed.
Quantitative Nanostructure Analysis of Silver Vanadium Phosphorus Oxide (Ag2VO2PO4) Battery Material Using X-Ray and Electron Microscopy
Authors: Ge Mingyuan , Yan Hanfei , Huang Xiaojing , Xin Huolin L. , Liu Wenjun , De Andrade Vincent , Marschilok Amy C , Takeuchi Esther S , Chu Yong S
Published: February 2020

With the state-of-art synchrotron-based X-ray and modern electron microscopy, the spatial resolution and measurement sensitivity have been significantly improved in analyzing materials’ nanostructure, by taking advantages of the high beam flux density or the source brightness. Associated with the ever brighter beam, it also brings the opportunity to investigate the beam effect to material structure modification, which is of significant interests in view of understanding the underlying physics, and it is also important to develop proper methodologies to use these state-of-the art probes to accurately characterize the intrinsic and extrinsic properties of materials.

In our work, we performed x-ray imaging experiment on single crystalline Ag2VO2PO4 battery material sample with a 15 nm resolution using the recently commissioned x-ray imaging capability at the Hard X-ray Nanoprobe Beamline at the National Synchrotron Light Source II.   Probe-induced electrochemical reaction was observed, which was revealed by the Ag reduction as well as diffusion and re-distribution of Ag.  In order to better understand the probe-induced electrochemical reactions, we also performed imaging experiments with other imaging methods: white-beam microdiffraction, transmission x-ray microscopy (TXM), and transmission electron microscopy (TEM). These probes deliver different levels of radiation does and provides different pathways for probe-induced structural modification.  This presentation will elaborate and quantify the probe-specific structural modifications.
Electrochemically Formed TiO2 Nanotube Arrays Site Selectively Decorated with Porous Au Particles By a Controlled Dewetting-Dealloying Approach - a Platform for Efficient Photocatalytic H2 Evolution
Authors: Nguyen Nhat Truong , Altomare Marco , Schmuki Patrik
Published: February 2020

In the last decades TiO2 has received large attention due to its ability to “photocatalytically” split H2O into H2 and O2. Under “open-circuit” conditions, noble metal-modified (mainly Pt, Au or Pd) TiO2 is needed for H2 photo-generation.1 Not only the presence but also the size, amount and distribution of the noble metal particles affect the photocatalytic efficiency of TiO2.2,3

In this contribution we show that a most effective way to control the size and distribution of co-catalytic nanoparticles deposited on ordered TiO2 nanotube arrays is a controlled sputter-dewetting process.4

For this, we first grow electrochemically highly-ordered arrays of short aspect-ratio TiO2 nanotube in a o-H3PO4/HF electrolyte.5 The tubes growth is based on a simple anodization of a Ti metal substrate in self-ordering electrochemical conditions, and the morphology of the formed tubular oxide structures can be simply adjusted by the experimental conditions. These arrays of TiO2 nanotubes are coated with sputtered Au and Ag films, and a following controlled thermal treatment is carried out that leads at the same time to Au-Ag alloying and thermal dewetting of the conformal metallic film, that is, the sputtered metals are converted into an array of orderly distributed alloyed Au-Ag nanoparticles.

By adjusting the sputtering conditions, we are able to selectively deposit the Au-Ag nanoparticles at the rim and/or within the cavity of the TiO2 nanotubes. Subsequently, we perform a dealloying process, consisting in the selective chemical dissolution of Ag in a HNO3 solution, this leaving behind nanoporous Au particles on/into the tubes. Compared to tubes decorated by conventional approaches, remarkably enhanced photocatalytic H2 production is obtained upon porousification of the embedded Au nanoparticles. These porous Au/TiO2 nanotube structures show a remarkable photocatalytic enhancement particularly when the Au porous particles are selectively formed at the rims of the tubes (“crown” position).

[1] K. Lee, A. Mazare, P. Schmuki, Chem. Rev.
2014, 114, 9385–9454.

[2] N. T. Nguyen, J. Yoo, M. Altomare, P. Schmuki, Chem. Commun.
2014, 50, 9653–9656.

[3] N. T. Nguyen, M. Altomare, J. E. Yoo, N. Taccardi, P. Schmuki, Adv. Energy Mater.
2015, doi: 10.1002/aenm.201501926.

[4] N. T. Nguyen, M. Altomare, J. Yoo, P. Schmuki, Adv. Mater.
2015, 27, 3208–3215.

[5] J. E. Yoo, K. Lee, M. Altomare, E. Selli, P. Schmuki, Angew.
Chem. Int. Ed.
2013, 52, 7514–7517.

Figure 1