bluuebunny/crossref_metadata_2025 huggingface dataset:
Citrate Effect on Reaction Kinetics of Pt Deposition on Pd(hkl) Via Surface Limited Redox Replacement of Cu UPD Monolayer
Authors: Brankovic Stanko , Yuan Qiuyi , Shao Minhua
Published: February 2020

The effect of citrate ions in reaction solution on reaction kinetics of Pt deposition on Pd via SLRR of Cu UPD monolayer has been studied[i]. Experiments involving both, single crystal Pd and Pd-nanoparticle substrates were performed. The results suggest that citrate has a suppressive role on Pt deposition kinetics which is manifested through the zero order reaction kinetics during red-ox process[ii]. The citrate adsorbed phase on Pd surface has mainly transport hindering role for upcoming Pt ions. The IR data suggest that Pt monolayers produced from citrate containing electrolyte have weaker electrosorption ability for CO than bulk Pt and Pd. This information should be useful in further application of citrates as reactant and additive for Pt deposition via SLRR which can be used to fine tune Pt monolayer reactivity on different substrates[iii]. The reaction kinetics model was developed to analyze our kinetics data where the citrate effect was described as an extra barrier for the Pt ion transport. The model is capable of predicting the reaction rate constants from known concentrations of the citrate and platinum ions in the solution using only two model parameters, X and B3. Both parameters have the real physical meaning which could be directly visualized as the additional diffusion path for Pt ions due to the presence of adsorbed citrate layer on CuUPD/Pd-NP surface. The analytical work could be further applied in design and development of more sophisticated apparatus for Pt-shell Pd-core catalyst synthesis. This aspects will be discuss in the conclusion of the talk.

The authors acknowledge the private funding of this work and the support from NSF Chemistry division under the contract # 0955922.

References:

[i]) S. R. Brankovic, J. X. Wang and R.R. Adzic, Surface Science, 474, L173 (2001).

[ii]D. Gokcen, S.-E. Bae, S.R. Brankovic, Electrochimica Acta,
56, 5545 (2011).  

[iii] S. R. Brankovic et al, submitted.
Coatings Based on Conducting Polymers and Functionalized Carbon Nanotubes with Anionic Surfactants Obtained By Electropolymerization
Authors: Branzoi Florina , Branzoi Viorel , Pahom Zoia
Published: February 2020

Nanocomposite films based on 3,4 ethylen-dioxythiophene, 2-aminophenol with functionalized single-walled carbon nanotubes (SWANTs- polyaminobenzene sulfonic acid - CNT-PABS, SWANTs- with carboxylic acids functionalized - CNT-COOH) and different anionic surfactants as dopants (sodium dioctyl sulfosuccinate - AOT, sodium dodecylbenzenesulfonate - SDBS) were studied. It was fabricated by a simple oxidative electropolimerization method.

All the obtained composites showed improved mechanical integrity, higher electronic and ionic conductivity and exhibited larger electrode specific capacitance than the polymer alone. These nanoporous composite films were grown electrochemically from aqueous solutions such that constituents were deposited simultaneously onto substrate electrode.

The synthetic, morphological and electrical properties of the obtained nanocomposite films were compared. Scanning electron microscopy (SEM) revealed that the composite films consisted of nanoporous networks of SWCNTS (single-walled carbon nanotubes) coated with polymeric film. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated that these composite films had similar electrochemical response rates to pure polymeric films but a lower resistance and much improved mechanical integrity. The negatively charged functionalized carbon nanotubes (CNTSF) served as anionic dopant during the electropolymerization to synthesize polymer/CNTSF composite films. The electrochemical and physical properties of the resulting composites were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and FT-IR spectroscopy techniques.The specific electrochemical capacitance of the composite films is a significantly greater value than that for pure polymer films prepared similarly. Using these composite films doped with anionic surfactants, the modified electrodes with improved properties were obtained.

Figure 1
Electrodeposition of PbO2 on Reticulated Vitreous Carbon for Organic Electrooxidation
Authors: Ruotolo Luis Augusto Martins , Farinos Rosimeire Martins
Published: February 2020

The problems caused by the growing of the environmental contamination by organics have been calling the attention of researches, authorities, and population in general since their effects have been more present in our lives. Environmental contamination can be avoided by using, in most cases, biological treatments; however, some classes of compounds are refractory to this kind of treatment and require different technologies to oxidize the organic compound.

In this context, the electrochemical technology emerged as an alternative environmentally, technically, and economically viable. Advantages of electrochemical technology are elimination of transport and storage of hazardous chemicals, reduction of the workmanship, and ease to automatization. Despite these advantages, for the effective use of the electrochemical technology for effluent treatment some drawbacks must be overcome, mainly mass transfer limitations resulting of the low concentrations in industrial effluents, which affect the current efficiency and the energy consumption.  As an attempt to improve mass transfer, in this work we address the electrochemical oxidation using three-dimensional electrodes of reticulated vitreous carbon (RVC) covered by PbO2film as the electroactive material.

The RVC/PbO2 electrode was prepared in a flow electrochemical reactor. The PbO2 film was electrodeposited on RVC applying different charges by varying the current density and electrolysis time. The porosities (in pores per inch) of the RVC substrates were 45, 60, and 80 ppi. The electrode was characterized by electrochemical techniques and scanning electronic microscopy. The decolorization reaction of the reactive blue 19 dye was used to evaluate the electrocatalytic power of the RVC/PbO2and compared to the flat plate electrode.

The results for the 45 ppi RVC showed that the PbO2electrodeposition was not uniform within RVC due to non-uniform current penetration (Fig. 1 and 2). The best electrodeposit morphology and uniformity was obtained applying low current densities for longer electrolysis time (Fig 1c).  Contrary, fast decolorization rate was obtained using the films deposited applying high current density (Fig. 2).

A comparison between the flat plate and RVC/PbO2electrodes in Fig. 3 shows that the three-dimensional electrode was very effect to remove color.

In order to increase the electrode specific surface area, PbO2 films were electrodeposited on RVC with 60 ppi and 80 ppi. After current density optimization, the PbO2 film was successfully deposited on the 60 ppi RVC.  On the other hand, an optimum current density cannot be found in order to obtain a uniform deposit on the 80 ppi RVC.  Moreover, the low porosity of this electrode and the high hydrophobic nature of RVC led to low surface wettability, thus contributing for the uneven PbO2 film.

Figure 1
Electrochemical Nuclear Waste Management Using Ionic Liquids: Controlled Electrodeposition of Fission Platinoids
Authors: Biddinger Elizabeth J , Shrestha Sujan
Published: February 2020

Ionic liquids (ILs) have low flammability, wide liquidus range, metal complexing ability, moderate-to-high conductivity, and wide electrochemical window (1, 2). Utilizing these properties of ILs, processes for nuclear waste management could be developed which are safer, more tunable and more streamlined than existing processes based on extracting agents such as tri-n-butyl phosphate (TPB) and volatile organic compounds such as kerosene or dodecane (3). In such IL-based processes, electrodeposition of metals will follow their extraction from aqueous sludge of nuclear wastes (4). Hence, understanding electrodeposition behavior of metals in ILs is of critical importance to the IL-based nuclear waste management processes.

In this work electrodeposition of fission platinoids (Pd, Rh and Ru) in ILs is investigated using their non-radioactive counterparts. The recovery of fission platinoids is important not only from the nuclear waste management perspective, but also from economic viewpoint as these metals are expensive and highly utilizable (5).

First, electrochemical behaviors of Pd, Rh and Ru were studied in suitable ILs. The objective of the studies was to understand how the electrochemical behavior of Pd in candidate ILs changes in the presence of Rh and Ru. Similar studies were also done with Rh and Ru to find out how their electrochemical behavior changes in the presence of other fission platinoids. Then, electrodeposition behaviors of the metals were examined on Ni substrates. Pd was found to electrodeposit on Ni substrate in 1-butyl-1-methylpyrrolidinium dicyanamide ([Bmpyrr][DCA]) forming an uniform film as shown in Figure 1. Similarly, electrodeposition of Rh and Ru were carried out. The goal was to do selective electrodeposition of these metals guided by the knowledge gained from the electrochemical behavior studies.

References

1.         S. Z. E. Abedin, M. Polleth, S. A. Meiss, J. Janek and F. Endres, Green Chemistry, 9, 549 (2007).

2.         A. P. Abbott, G. Frisch and K. S. Ryder, Annual Review of Materials Research, 43, 335 (2013).

3.         S. Ha, R. Menchavez and Y.-M. Koo, Korean Journal of Chemical Engineering, 27, 1360 (2010).

4.         X. Sun, H. Luo and S. Dai, Chemical Reviews, 112, 2100 (2011).

5.         Z. Kolarik and E. V. Renard, Platinum Metals Review, 49, 79 (2005).

Figure 1. SEM image of Pd deposits on Ni substrate after potential hold of -0.524 V vs Fc/Fc+ for 1 h in a solution of 25 mM PdCl2 in 1-butyl-1-methylpyrrolidinium dicyanamide ([Bmpyrr][DCA]) at room-temperature.

Figure 1
Effect of Bath Composition on the Composition and Morphology of Electrodeposited Ag-Cu Alloys
Authors: Karakaya Ishak , Ulu Fulya , Demirci Gökhan , Erdogan Metehan
Published: February 2020

One of the common brazing alloys, CusilTM, has eutectic composition of 72 % silver and 28 % copper. The electrochemical codeposition of Ag and Cu is difficult due to the large difference between the standard reduction potentials of silver (0.799 V) and copper (0.337 V). A complex ion bath containing KAg(CN)2, CuCN, KCN and K4P2O7 was used to overcome this difficulty and bring the reduction potentials closer to each other.

The effects of KAg(CN)2, KCN and K4P2O7 concentrations on the composition and microstructure of electrodeposited Ag-Cu films was investigated in this study. The effect of K4P2O7 addition to the electrolyte was examined in a set of experiments by employing a three-level full-factorial statistical design. The concentrations of bath ingredients: KCN, KAg(CN)2 and K4P2O7 were the factors that were investigated. The levels of the design were chosen at the minimum, mean and maximum amounts of the three factors. Therefore, (33) 27 experiments were designed to investigate the effects of changes in bath concentration on composition and morphology of deposits. All the other plating parameters were fixed during the experiments.

The increase in K4P2O7 concentration caused a minor decrease in Ag content of the film where the increase in KCN and KAg(CN)2 concentrations caused major increases in Ag contents. The microstructures of deposits were found to be globular clusters when high KAg(CN)2 concentrations were used. K4P2O7 addition to the electrolyte suppressed cluster formation and produced more compact microstructures. Increasing the KCN concentration resulted in deposits having finer microstructures and higher Ag contents.
New High Conductivity Membranes for Alkaline Electrolyzers
Authors: Chen Qingmei , Liu Zengcai , Kutz Robert , Yang Hongzhou , Masel Richard I , Lewinski Krzysztof A. , Kaplun Marina , Matthews Tyler Scott
Published: February 2020

This talk will describe the properties of a new DX series of high conductivity membranes for alkaline electrolyzers.  These membranes were originally developed for use in alkaline carbon dioxide electrolyzers and have recently been tested in alkaline water electrolyzers.   Table 1 compares the membrane conductivity of these membranes to others.  Notice that the conductivity is higher than many of the other membranes that have been used in alkaline electrolyzers. 

Table 1 A comparison of the conductivity of the new membranes to a selection of previously published membranes

Membrane             Conductivity

Tokuyama A201    0.04 S/cm at 24 °C1

Selemion AMV      0.005 S/cm at 24 °C2

qPVB/Cl                0.016 S/cm at 25 °C3

QA-ETFE               0.03 S/cm at 24 °C4

DX4-13                 0.07 S/cm at 24 °C

We have tested the membranes in both alkaline CO2 and alkaline H2O elecctrolyzers.  Results are shown in Tables 2 and 3.  Notice that the performance is quite good. 

Table 2  Performance of a variety of membranes in an alkaline CO2 electrolyzer at room temperature.  All of the results were measured with a ruthenium oxide anode catalyst and a silver cathode catalyst under identical conditions.

Membrane             CO current

Nafion                   0 ma/cm2

Neosepta                8 mA/cm2

AMI-7001 (qPVB/Cl)              3.5 mA/cm2

DX4-13                 110 mA/cm2

DX5-13                 270 mA/cm2

Table 3 Performance of a variety of membranes in an alkaline water electrolyzer  near room temperature

Selemion AMV      90 mA/cm2 at 2V at 30 °C2

qPVB/Cl                50 mA/cm2 at 2V at 25 °C3

QA-ETFE               120 mA/cm2 at 2V at 25 °C4

DX4-13                 400 mA/cm2 at 23 °C

These and other results will be discussed. 

References

1.            Duan, Q., S. Ge, and C.-Y. Wang, Water Uptake, Ionic Conductivity and Swelling Properties of Anion-Exchange Membrane. Journal of Power Sources, 2013. 243(0): p. 773-778.

2.            Seetharaman, S., R. Balaji, K. Ramya, K.S. Dhathathreyan, and M. Velan, Graphene Oxide Modified Non-Noble Metal Electrode for Alkaline Anion Exchange Membrane Water Electrolyzers. International Journal of Hydrogen Energy, 2013. 38(35): p. 14934-14942.

3.            Cao, Y.-C., X. Wu, and K. Scott, A Quaternary Ammonium Grafted Poly Vinyl Benzyl Chloride Membrane for Alkaline Anion Exchange Membrane Water Electrolysers with No-Noble-Metal Catalysts. International Journal of Hydrogen Energy, 2012. 37(12): p. 9524-9528.

4.            Wu, X. and K. Scott, A Polymethacrylate-Based Quaternary Ammonium Oh− Ionomer Binder for Non-Precious Metal Alkaline Anion Exchange Membrane Water Electrolysers. Journal of Power Sources, 2012. 214(0): p. 124-129.
The Importance of Surface OXIDE FILMS in Metal Dissolution Processes - a 20-Year Update
Authors: MacDougall Barry R.
Published: February 2020

The presenter will update his 1995 presentation [ECS Vol. 95-19], which he presented in accepting the 1995 Carl Wagner Award of the ECS. A lot has happened since 1995, but the basics of high-rate EC dissolution processes are still there. As in 1995, I will try to show that these fundamental processes are not only important for High Rate Dissolution, but to many other areas of electrochemical science and technology as well [corrosion, semiconductors, electro-deposition, electro-synthesis and industrial elecrolytics, organic-electrochemistry, etc.]. I will draw upon my 45+ years in the field to highlight what I think are the parallels between the different areas, and how the potentially significant benefits of "cross-fertilization of knowledge" from different EC disciplines needs to be considered at least a bit seriously for maximum benefit.
(Invited) Development of Tailor Made Donor-Acceptor Pairs for Fullerene-Free Organic Solar Cells
Authors: Welch Gregory Charles
Published: February 2020

Organic solar cells (OCS) are now an established clean energy technology.1 These photovoltaic devices can be printed at low temperatures onto large area, flexible substrates, and can be made semi-transparent, making them a low-cost alternative to traditional inorganic devices, and can be utilized in many niche applications.  Current state-of-the art relies on a polymer-fullerene bulk-heterojunction active layer, with power conversion efficiencies reaching 10%.2 While promising, certain limitations have prevented large scale commercialization. In an effort to advance OCS, the development of low-cost and sustainable active layer materials that can be mass-produced and yield high performance devices is essential. One area of our research at Dalhouise University centers on the development of small molecue based organic p-conjugated materials to replace the common fullerene acceptors.3 This talk will highlight our materials design strategy and discuss key thin-film characterization data and solar cell performance.

(1)          Su, Y.-W.; Lan, S.-C.; Wei, K.-H. Mater. Today
2012, 15, 554.

(2)          Li, G.; Zhu, R.; Yang, Y. Nat. Photonics
2012, 6, 153.

(3)          Eftaiha, A. F.; Hill, I. G.; Sun, J.-P.; Welch, G. C. J. Mater. Chem. A
2014, 2, 1201.
(Invited) Conducting Polymer Transistors Making Use of Activated Carbon Gate Electrodes
Authors: Tang Hao , Kumar Prajwal , Zhang Shiming , Santato Clara , Soavi Francesca , Cicoira Fabio
Published: February 2020

The characteristics of the gate electrode have significant effects on the behaviour of organic electrochemical transistors (OECTs), which are intensively investigated for applications in the booming field of organic bioelectronics. In this work, high specific surface area activated carbon (AC) was used as gate electrode material in OECTs based on the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS).1 We found that the high specific capacitance of the AC gate electrodes leads to high drain-source current modulation in OECTs.

Cyclic voltammetry studies, where PEDOT:PSS is used as the working electrode (WE) and AC is used as the reference electrode (RE) and counter electrode (CE), show that high double-layer capacitance and absence of Faradaic processes permit the development of stable OECTs where the channel potential is uniquely determined by the applied gate bias. The intrinsic quasi-reference characteristics of AC electrodes make unnecessary the presence of an additional reference electrode to monitor the OECT channel potential.

The ease of process of AC electrodes for in plane, flexible device architectures constitutes a step forward in the search of new electrode materials for OECTs to be used in iontronics, printed electronics, bio analytical sensing, and other organic bioelectronic devices.
(Invited) Innovations in Organic Printed Optoelectronics
Authors: Kippelen Bernard
Published: February 2020

Printed organic electronics, a technology based on organic semiconductors that can be processed into thin films using vacuum processing or conventional printing and coating techniques, has been the subject of active research and development over the past decades. A range of solid-state devices, including organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), photodiodes, sensors, and solar cells, have been demonstrated with this new class of materials. However, despite a steady progress in performance, many challenges remain and further scientific and technological advances are required before this emerging technology can unleash its full potential.

In this talk, we will review recent advances in materials, devices, and processing for organic printed optoelectronics. In a first part, we will review the electronic properties of organic semiconductors with an emphasis on their differences with conventional inorganic semiconductors and oxides. We will discuss progress in various device platforms, including organic light-emitting diodes, organic solar cells, photodetectors, sensors, and organic field-effect transistors. New materials, unconventional device architectures and new processing techniques illustrate the versatility of organic photonics and electronics, and the potential of this field to lead to disruptive innovations. We will show that recent progress in device performance, stability, and packaging are likely to accelerate the deployment of these technologies. Strategies to reduce the overall environmental impact of the new products enabled by this emerging technology during their life-cycle will also be presented. Finally, we will discuss how organic semiconductors can be used to design devices with a performance level that exceeds that of inorganic device platforms. 

The talk is intended for scientists and engineers who want to learn the state-of-the-art in organic semiconductors for optoelectronics and energy. It is also intended for innovators, investors and industry analysts who want to understand the evolutionary trends of the emerging markets associated with organic printed optoelectronics.
(Invited) Measurement of the Energy-Band Relations of Stabilized Si Photoanodes Using Operando Ambient Pressure X-ray Photoelectron Spectroscopy
Authors: Richter Matthias Hermann , Lichterman Michael Frankston , Hu Shu , Crumlin Ethan J , Mayer Thomas , Axnanda S , Favaro Marco , Drisdell Walter , Hussain Z , Brunschwig Bruce , Lewis Nathan S. , Liu Z , Lewerenz Hans Joachim
Published: February 2020

Amorphous TiO2 coatings can stabilize semiconductor photoanodes such as Si, GaAs, and GaP that are otherwise unstable in aqueous media 1-3. We employ Ambient Pressure Photoelectron Spectroscopy 4,5 and standard X-Ray Photoelectron Spectroscopy to analyze light-absorber/protection-layer/catalyst stacks. The photoelectrochemistry coupled with AP-PES investigations have been performed at the Advanced Light Source, Berkeley at Beamline 9.3.1.

We show that the holographic information contained in the shape and width of core level peaks allows for determination of the electrostatic potential of semiconductor junctions by X-Ray photoelectron spectroscopy. Results for transition metal oxide protected light absorbers for photoelectrochemical energy conversion are shown. Energy band alignments at the light absorber/protection layer interface and for light-absorber/protection-layer/catalyst stacks with and without contact with aqueous electrolytes are investigated; evaluations with respect to semiconductor band bending and interfacial dipole shifts are presented.

1. S. Hu et al., Science, 344, 1005–1009 (2014).

2. M. F. Lichterman et al., Energy Environ. Sci., 7, 3334–3337 (2014).

3. H. J. Lewerenz, in Photoelectrochemical Materials and Energy Conversion Processes, R. C. Alkire, D. M. Kolb, J. Lipkowski, and P. N. Ross, Editors, vol. 12, p. 61–181, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany (2010).

4. S. Axnanda et al., Meet. Abstr., MA2013-02, 921–921 (2013).

5. S. Axnanda et al., (2014), submitted.
Molecular Structure and Ion Transport Near Graphite-Electrolyte Interfaces in Lithium-Ion Batteries
Authors: Lordi Vincenzo , Ong Mitchell T. , Draeger Erik W. , Pask John E. , Verners Osvalds , van Duin Adri
Published: February 2020

The performance of lithium-ion secondary batteries is strongly tied to ionic transport through electrode-electrolyte interfaces. Ion solvation structures near the interface as well as the chemistry of the electrode surface, in particular the edge termination of graphite electrodes, can impact Li ion transport into and out of the electrode. Understanding these effects is critical to optimizing battery performance. We have performed molecular dynamics simulations of organic liquid electrolytes in contact with graphite electrodes, with and without electric field, to understand the relationship between ion solvation structure and transport near the interface. Prototypical electrolytes consisting of ethylene carbonate (EC) or ethyl methyl carbonate (EMC) organic solvent containing dissolved LiPF6 salt were studied, in contact with armchair-edge oriented graphite electrodes. Various surface terminations of the graphite, including H and OH, were compared. We find that Li+ maintains a well-structured solvation shell even when an electric field is present. The bulkier PF6
– anion does not present a strong solvation structure and exhibits much higher mobility in an electric field. We further observe an energy barrier for Li+ insertion into graphite, particularly when the surface is hydroxyl terminated. Lithium extraction, however, is facile even against an applied electric field. The energetics of Li+ insertion and extraction were analyzed using density functional theory to sample the free energy surfaces.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Support for this work was provided through Scientific Discovery through Advanced Computing (SciDAC) program funded by U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences.
Graphene-Coated Separators As Effective Polysulfide Traps in Lithium-Sulfur Batteries
Authors: G Kannan Aravindaraj , Shin Won-Kyung , Kim Dong-Won
Published: February 2020

The increasing demand for rechargeable lithium batteries with higher energy densities for applications such as electric vehicles and grid-scale energy storage systems has led to the intensive search for advanced energy storage systems beyond the current lithium-ion battery technology.  Lithium-sulfur (Li-S) batteries have become the preferable choice among the next-generation energy storage systems due to their high theoretical capacity (1675 mAh g-1), high specific energy density (2600 Wh kg-1) and abundant availability in the earth’s crust. In addition, the elemental sulfur is non-toxic and cheap.  However, the inherent disadvantages of Li-S batteries such as the highly insulating (both ionically and electronically) nature of sulfur that requires a large of amount of inactive conductive additives, dissolution of lithium polysulfides into the electrolyte solution and the migration of lithium polysulfides to the anode side, need to be overcome to realize their practical applications.  These problems result in low utilization of sulfur and rapid capacity fading during cycling. Various strategies such as encapsulating sulfur using conductive matrices (carbon, conducting polymers and metal oxides), using polysulfide traps on the cathode side and covering the anode with a protective layer have been adopted to mitigate these problems.  In our study, graphene-coated separators have been prepared and investigated as effective lithium polysulfide traps to prevent the migration of polysulfides to the anode side. Detailed characterization of the graphene-coated separator and its performance as a polysulfide trap in Li-S cells will be presented.  Also, the effect of coating thickness and the surface functional groups on the Li-S cell performance will be discussed.
Sustainable Performance of Li-S Battery Using Ultramicroporous Carbon-Sulphur Composite Electrode in Carbonate Based Electrolyte
Authors: Maria Joseph Helen , Munnangi Anji Reddy , Diemant Thomas , Jürgen Behm Rolf , Fichtner Maximilian
Published: February 2020

Lithium-sulphur (Li-S) batteries are being considered for high-energy storage applications due to the high theoretical specific capacity (1672 mAh g-1) and energy density (2600 Wh kg-1) of sulphur.1-3 However, the Li-S battery technology suffers from poor cycle life.4,5 The electrochemical reaction of lithium with cyclic octa sulphur (S8) leads to the formation of higher order polysulphides (Li2Sx, x=4-8). These higher order polysulphides are highly soluble in liquid electrolytes and lead to the continuous depletion of the active material and trigger unwanted side reactions. Development of a sustainable cathode is the key factor for the advancement of Li-S batteries. Many efforts were put into the improvement of the Li-S batteries. One promising approach is microporous carbon confined sulphur, which eliminates the formation of higher order polysulphides.6

Herein, we report an easily scalable, inexpensive ultramicroporous carbon confined sulphur composite cathode and its sustainable performance in Li-S cell using commercial carbonate based electrolyte. The ultramicroporous carbon sulphur (UC-S) composite with a sulphur loading of 46 % exhibits a reversible capacity of 700 mAh g-1 at C/5 (335 mA g-1) even after 100 cycles (Figure 1). The observed cycling stability was attributed to the direct formation of low order polysulphides (Li2S2/ Li2S) during the discharge process of UC-S cathode. For the first time we have examined and validated the lithiation/delithiation mechanism and the mechanism of capacity fading over cycling for sulphur confined in microporous carbon cathode by analysing the subsurface using XPS.

References

B.C. Melot and J.-M. Tarascon, Acc. Chem. Res., 2013, 46 (5), 1226–1238.

X. Ji, and L.F. Nazar, J. Mater. Chem., 2010, 20, 9821–9826.

A. Manthiram, Y. Fu, Y.S. Su, Acc.
Chem. Res.
2013, 46, 1125–1134.

J. Shim, K.A. Striebel, E.J. Cairns, J. Electrochem. Soc.
2002, 149 (10), A1321–A1325.

B. Scrosati, J. Hassoun and Y.-K. Sun, Energy Environ. Sci.
2011, 4, 3287–3295.

S. Xin, L. Gu, N-H. Zhao, Y-X. Yin, L-J. Zhou, Y-G. Guo and L-J. Wan, J. Am. Chem. Soc.
2012, 134, 18510−18513.

Figure 1
Synthesis and Characterization of Li2FeSiO4 As Candidate High-Capacity Li-Ion Battery Cathode Material
Authors: Wei Huijing , Lu Xia , Chiu Hsien-Chieh , Arthur Zachary , Chen Ning , Zhou Jigang , Gauvin Raynald , Reid Joel , Jiang De-Tong , Hovington Pierre , Guerfi Abdelbast , Zaghib Karim , Demopoulos George P.
Published: February 2020

Due to the emerging needs of electrical and hybrid electrical vehicle applications, more research effort has been directed towards the next generation Li-ion storage materials, especially on high-capacity cathode materials. In this context, lithium transition metal silicates Li2

M
SiO4 (
M
= Fe, Mn, Co, etc.) 1-5 are drawing increasingly more attention thanks to their high theoretical capacity due to the two lithium-ion extraction per formula unit. However lack of phase purity control during synthesis and phase transition reactions during delithiation/lithiation have imposed obstacles to their study and further development. Hereby, we investigate a novel dual step organic-assisted hydrothermal-annealing approach to obtain different lithium iron silicate polymorphs (monoclinic, orthorhombic, and mixed) for subsequent electrochemical evaluation and probing of their phase transition behavior. During the hydrothermal synthesis step, organic additives are used to control nanocrystal growth, which upon annealing lead to in-situ coating with nitrogen-doped carbon. The silicates are characterized by various techniques including XRD, FE-SEM, TEM, XPS, Raman spectroscopy, and XANES and demonstrate different structures and morphologies with various synthesis conditions, including annealing temperature, pH etc., which critically impact on their electrochemical properties.

References

1. Nyten, A., Abouimrane, A., Armand, M., Gustafsson, T. & Thomas, J. O. Electrochemical performance of Li2FeSiO4 as a new Li-battery cathode material. Electrochem Commun
7, 156-160, (2005).

2. Nishimura, S. I. et al. Structure of Li2FeSiO4. J Am Chem Soc
130, 13212-13213, (2008).

3.Boulineau, A. et al. Polymorphism and structural defects in Li2FeSiO4. Dalton Trans
39, 6310-6316, (2010).

4. Eames, C., Armstrong, A. R., Bruce, P. G. & Islam, M. S. Insights into Changes in Voltage and Structure of Li2FeSiO4 Polymorphs for Lithium-Ion Batteries. Chem Mater
24, 2155-2161, (2012)

5. R.J. Gummow, Y. He / Journal of Power Sources 253 (2014) 315-331, Recent progress in the development of Li2MnSiO4 cathode materials
Enhanced Electrochemical Characteristics of the Pani-Coated Sulfur Cathode
Authors: Hyun Jung Eun , Um Jaeeun , Lee Suk-Hyun , Jung Myung-Jo , Ishihara Tatsumi
Published: February 2020

The dissolution of polysulfides from the cathode remains a key roadblock in the advancement of Li-S batteries. To prevent polysulfide dissolution and improve the performance of Li-S battery, PANi-coated sulfur cathode is prepared using 2L reaction vessel. Using the different sulfur ratio, the performance test is conducted, which results that 33 wt% sulfur PANi composite shows best performance.

The PANi-coated sulfur composite cathode was composed of 70 wt% of the PANi-coated sulfur composite, 20 wt% of vapor grown carbon fiber, and 10 wt% of binder (kynar 761). The bare sulfur cathode also had a similar composition (70 wt% of sulfur, 20 wt% of vapor-grown carbon fiber, and 10 wt% of binder (kynar 761)). The sulfur loading of the electrodes was about 4.5 mg cm-2. The electrode slurry was coated on an aluminum sheet (15 µm).
Designing High Voltage Electrolytes Based on Boron Clusters for Magnesium Batteries
Authors: Tutusaus Oscar , Mohtadi Rana , Arthur Timothy S. , Mizuno Fuminori
Published: February 2020

Multivalent battery systems such as rechargeable magnesium (Mg) batteries have been proposed as candidates for post-lithium battery systems. In particular, Mg anode allows for a higher volumetric capacity (3833 mAh cm-3 vs 2046 mAh cm-3 for Li metal), while providing safer energy storage due to the formation of a protective film on the metal surface upon exposure to air or moisture. The feasibility of Mg battery technology was demonstrated in 2000, with the report of the one and only prototype to date.[1] Despite the progress achieved to date, the main challenge in Mg battery development is the identification of a suitable electrolyte. The electrolyte should offer a large electrochemical window, and be compatible with battery components, such as Mg metal, high voltage cathodes and non-noble current collectors. While the vast majority of the available electrolytes contain halides in their structure, rendering them corrosive to non-noble metals,[2] our group recently introduced magnesium borohydride as an alternative chloride-free electrolyte system.[3] We are currently focusing on increasing the oxidative stability of borohydride anion by exploring larger boron hydride species such as polyhedral boron clusters.[4] To that regard, we recently reported a magnesium carborane Grignard complex as the first proof-of-concept of a highly stable magnesium electrolyte of the B-H based family.[5] This presentation will provide our latest results on the use of boron clusters in the design of magnesium electrolytes stable in contact with Mg metal, display an electrochemical window limited solely by solvent decomposition, and are compatible with non-noble metal electrodes.

References:

[1] D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich, E. Levi, Nature
2000, 407, 724-727.

[2] J. Muldoon, C. B. Bucur, A. G. Oliver, J. Zajicek, G. D. Allred, W. C. Boggess, Energy Environ. Sci.
2013, 6, 482-487.

[3] R. Mohtadi, M. Matsui, T. S. Arthur, S.-J. Hwang, Angew. Chem. Int. Ed.
2012, 51, 9780 –9783.

[4] O. Tutusaus, R. Mohtadi, ChemElectrochem 2014, DOI:10.1002/celc.201402207

[5] T. J. Carter, R. Mohtadi, T. S. Arthur, F. Mizuno, R. Zhang, S. Shirai, J. W. Kampf, Angew. Chem. Int. Ed.
2014, 53, 3173 –3177.
Compatibility Studies of New Hückel-Type-Based Electrolytes with Electrode Materials
Authors: Bitner-Michalska Anna , Nolis Gene M , Trzeciak Tomasz , Zukowska Grazyna Zofia , Niedzicki Leszek , Wieczorek Wladyslaw , Marcinek Marek
Published: February 2020

Sodium has emerged as a major contender to lithium for rechargeable battery applications. Owing to its strengths are its high abundance, low production costs and suitable redox potential (Na/Na+, Eo = -2.71 V, not much less than Li/Li+, E˚=-3.05 V vs. standard hydrogen electrode). However, much like the lithium-ion battery industry, researchers are aware of how critical the electrolyte plays into cell performance. The novel imidazolate sodium salts: sodium 4,5-dicyano-2 (trifluoromethyl)imidazolate (NaTDI), sodium 4,5-dicyano-2-(pentafluoroethyl)imidazolate (NaPDI) and sodium pentacyanopropenide  (NaPCPI)  are presented [1]. Novel salts present interesting properties for electrolytes with applications in sodium and sodium-ion batteries.

These salts may be synthesized easily and have low cost of production on the industrial scale, but also possess very interesting ionic conductivity in solution containing EC/DMC (Graph 1.). Moreover, the salts studied exhibit electrochemical stability against anode (Graph 2.) and cathode. Electrode materials have been produced by two techniques: tape casting (cathode and anode) and Microwave Plasma Chemical Vapor Deposition (anode) [2]. Presented anodes are based on germanium and antimony.

References:

[1] L. Niedzicki, E. Karpierz, A. Bitner, M. Kasprzyk, G.Z. Zukowska, M. Marcinek, W. Wieczorek, Optimization of the lithium-ion cell electrolyte composition through the use of the LiTDI saltElectrochim. Acta 117C (2014) 224-229

[2] M. Marcinek, L. Hardwick, G. Żukowska, R. Kostecki, Microwave Plasma Chemical Vapor Deposition of Graphitic Carbon Thin Films, Carbon 48 (2010) 1552-1557

Figure 1
Effect of Drying in Electrode Processing for Energy Storage
Authors: Stein Malcolm , Mukherjee Partha P.
Published: February 2020

Despite the wide range of ideal applications for LIBs, there is still room for improvement in their performance. The effects of varying the composition and chemistry of LIBs are well documented [1-2], however a critical aspect that is often overlooked is the processing steps during fabrication. Typical processing parameters such as film thickness or evaporation have a large impact on critical parameters such as porosity of the electrodes, and thus can affect the electrochemical performance. During the solvent evaporation stage, a non-uniform distribution of electrode constituents can develop in cases where the solvent evaporation rate exceeds that of the diffusion rate of the mobile electrode constituents [3]. An even distribution of carbon black and binder throughout the electrode is crucial to ensuring the minimization of internal cell resistance, and therefore the maximum performance for a given electrode composition. 

In this work, we evaluate the impact of evaporation rate on the distribution of binder and carbon black in the electrode microstructure and the subsequent electrochemical performance. Both single-stage and two-stage evaporation was considered, where the two-stage process consisted of a slow rate followed by  oven-drying, and the single-stage consisted solely of immediate oven drying, with two different rates. Figure 1 shows the evaporation rate as a function of overall electrode sheet weight percent. Here the first stage for the two-stage sheet occurs over approximately 16 hours, with a loss of roughly 20% by weight. 

SEM images of the resulting microstructures indicate the vertical accumulation of carbon and binder on the surface of electrodes, with the increased carbon content in the case of the fast rate cases leading to the formation of a binder/carbon black composite that does not coat the active material particle surface, as shown in Figure 2. This through-plane (along the thickness) accumulation has been shown to decrease the rate performance, as shown in Figure 3.

The experimental results combined with theoretical analysis is expected to shed insight into the optimal drying conditions that may yield an optimum distribution of electrode constituents. 

References:

1.  M. Armand and J.M. Tarascon, Issues and Challenges  facing Rechargable Lithium Batteries. Nature, 414,      359 (2001).

2.  Handbook of Battery Materials, Second Edition. Edited by Claus Daniel and Jurgen O. Besenhard. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.

3.  A.F. Routh, Drying of Thin Colloidal Films. Rep. Prog.Phys., 76 (2013)

Figure 1
Fabrication and Characterization of All-Solid-state3D Li-Ion Microbatteries Based on TiO2 Nanotubes
Authors: Vacandio Florence , Knauth Philippe , Djenizian Thierry
Published: February 2020

The spectacular development of autonomous mobile systems has enhanced the race for the miniaturization of micropower sources. However, the storage performances of devices are seriously compromised when decreasing the size of the components down to the micrometer scale. This is particularly true for the development of all-solid-state microbatteries which are rapidly reaching performance limit in terms of energy and power densities. To overcome these issues, 3D microbatteries have attracted interest while remaining a technological challenge since it requires the marriage between materials science, electrochemistry, and microfabrication processes. In 2009, we proposed to use self-organized TiO2 nanotubes (ntTiO2) as a 3D negative electrode (Figure) for Li-ion microbatteries (Chem. Mater., 2009). This particular geometry is achieved by a simple electrochemical process (anodization) which improves significantly the electrochemical performance of the system. In this study will be proposed an all-solid-state 3D microbattery composed of a polymer electrolyte and a cathode material (LiFePO4) successively deposited at the surface of the nanotubes. While the nanotubes and polymer layers are obtained by electrodeposition process, the cathode material is achieved by cathodic sputtering. We will present in this work, the influence of morphology, structure and chemical composition of the cathode material on the electrochemical performance of the microbatteries in terms of areal capacity, rate capability, and capacity fading.

 References :

[1] B. Ellis, P. Knauth, and T. Djenizian, “Three-dimensional Self-supported Metal Oxides for Advanced Energy Storage”, Adv. Mater., DOI 10.1002/adma.201306126(2014). In press (IF : 14,829)

[2] N. Plylahan, M. Letiche, M. Barr, and T. Djenizian, “All-solid-state lithium-ion batteries based on self-supported titania nanotubes”, Electrochem. Commun., 43, 121, 2014 (IF : 4,425)

[3] N. Plylahan, N. A. Kyeremateng, M. Eyraud, F. Dumur, H. Martinez, L. Santinacci, P. Knauth, and T. Djenizian, “Highly conformal electrodeposition of copolymer electrolytes into titania nanotubes for 3D Li-ion batteries”, Nanoscale Res. Lett., 7, 349 (2012). (IF : 2,726)

[4] F. Vacandio, M. Eyraud, P. Knauth, and T. Djenizian, “Tunable electrical properties of self-organized zirconia nanotubes”, Electrochem. Commun., 13, 1060 (2011). (IF : 4,859)

[5] G. Ortiz, I. Hanzu, T. Djenizian, P. Lavela, J. L. Tirado, and P. Knauth, “Alternative Li-ion battery electrode based on self-organized titania nanotubes”, Chem. Mater., 21, 63 (2009).(IF : 7,286)

Figure 1
Improvement of Transport Properties in Li-Conducting Ceramic Oxides
Authors: Aguadero Ainara , Aguesse Frederic , Bernuy-López Carlos , Manalastas William Wang , López del Amo Juan Miguel , Kilner John A.
Published: February 2020

Li-conducting ceramic electrolytes can be used as ion-selective ceramic membranes adding chemical, thermal and electrochemical stability and preventing capacity fading with time. To date there has been low control of the processing conditions of these materials, however Li-ceramic conductors with high alkaline mobilities, have shown to react with moisture (Li-H exchange) and CO2 even at room temperature1. In recent works we have proven that this corrosion with moisture can promote a huge degradation of the phase purity, microstructure and transport properties and that the control of moisture during processing can improve Li-conductivity in ceramic oxides from 1 to 3 orders of magnitude1
,3.

In this work, we provide a better understanding of the importance of moisture control during the processing of Li-conducting ceramics as it is a limiting factor for their use as solid state electrolytes. For this purpose, we have studied two families of ceramic electrolytes: Li3xLa2/3-xTiO3 (LLTO) and Ga-doped Li7La3Zr2O12. Our approach in the Ga-doped garnet has been to dope in the tetrahedral Li-positions trying to optimize the Li-vacancy content and favour a higher Li-mobility in an octahedral-octahedral path. Impedance spectroscopy combined with 1H and 7Li solid state NMR and neutron power diffraction were used to analyse the cation environments and the effect of moisture on the Li-mobility while electron microscopy was used to evaluate the effect the local structure and microstructure of the dense samples.

We have proven a great effect of moisture on the miscrostructure and transport properties of ceramic oxides. We observed a substantial increase of the densification with densities around 92-95% when sintering under low moisture and CO2 content (< 2ppm). Furthermore, avoiding the corrosion process that leads to the Li-H exchange with the concomitant decrease of Li charge carriers and the formation of secondary phases in the grain surface (Fig. 1), we have increased by 5 times the total conductivity in LLTO2. Moreover, we have achieved a conductivity of 1.3x10-3 S/cm at 24oC for La3Zr2Li6.55Ga0.15□0.3O12which is amongst the highest Li ion conductivities reported for garnet-structured materials to date3.

References

1 a) Boulant, J. F. Bardeau,  A. Jouanneaux, J. Emery, J.-Y. Buzare,  O. Bohnke, Dalton Transactions 39, 3968, 2010 b) G. Larraz, A. Orera, M.L.  Sanjuan, J. Mater.
Chem. A., 1, 11419, 2013.

2 F. Aguesse, J. M. Lopez del Amo, V. Roddatis, A. Aguadero, John Kilner Advance Materials: Interfaces, 1300143, 2014

3 C. Bernuy-Lopez, W. Manalastas, A. Aguadero, J. M. Lopez del Amo, F. Aguesse, J. A. Kilner, Chemistry of Materials, 26, 3610, 2014

Figure 1
A Study on the Catalytic Activity of Noble Metal Nanoparticles on Reduced Graphene Oxide for Oxygen Evolution Reactions in Lithium-Air Batteries
Authors: Jeong Yo Sub , Jung Hun-Gi , Park Jin-Bum , Kim Jooho , Lu Jun , Amine Khalil , Sun Yang-Kook , Scrosati Bruno , Lee Yun Jung
Published: February 2020

Among many challenges present in Li-air batteries, one of the main reasons of low efficiency is the high charge overpotential due to the slow oxygen evolution reaction (OER). Here we present systematic evaluation of Pt, Pd, and Ru nanoparticles supported on rGO as OER electrocatalysts in Li-air cell cathodes with LiCF3SO3-TEGDME salt-electrolyte system. All of the noble metals explored could lower the charge overpotentials, and among them, Ru-rGO hybrids exhibited the most stable cycling performance and the lowest charge overpotentials. Role of Ru nanoparticles in boosting oxidation kinetics of the discharge products were investigated. Apparent behavior of Ru nanoparticles was different from the conventional electrocatalysts that lower activation barrier through electron transfer, since the major contribution of Ru nanoparticles in lowering charge overpotential is to control the nature of the discharge products. Ru nanoparticles facilitated thin film-like or nanoparticulate Li2O2 formation during oxygen reduction reaction (ORR), which decomposes at lower potentials during charge, although the conventional role as electrocatalysts during OER cannot be ruled out. Pt-and Pd-rGO hybrids showed fluctuating potential profiles during the cycling. While Pt- and Pd-rGO decomposed the electrolyte after electrochemical cycling, no electrolyte instability was observed with Ru-rGO hybrids. This study provides the possibility of screening selective electrocatalysts for Li-air cells while maintaining electrolyte stability.