bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Sputter Growth of Chalcogenide Superlattice Films for Future Phase Change Memory Application
Authors: Saito Yuta , Mitrofanov Kirill V , Makino Kotaro , Miyata Noriyuki , Fons Paul , Kolobov Alexander V. , Tominaga Junji 
Published: February 2020

Ge-Sb-Te ternary alloys are key materials for phase-change random access memory (PCRAM). In PCRAM, data recording relies on reversible switching between amorphous and crystalline phases by electrical pulse induced Joule heating. We have proposed and developed GeTe/Sb2Te3 superlattice phase change memory, which is known as interfacial phase change memory (iPCM), and have demonstrated a significant reduction in switching energy and much longer endurance compared to conventional alloy-type phase change memory.
Since this superlattice is composed of atomically aligned GeTe and Sb2Te3 multilayers, fabricating a highly-oriented film is crucial. Furthermore, in order to utilize such material for novel devices in an industrial setting, reliable processes that allow large area deposition of uniform films is critical. Sputtering is one of the most useful, technologically friendly, and reliable methods for thin film fabrication. In this work, the growth mechanism of layered chalcogenide films is discussed.
The superlattice films were grown on various substrate materials by radio-frequency magnetron sputtering. Ge-Te and Sb-Te alloy targets were used. Before the growth of the film, Ar sputter cleaning was carried out to remove a native oxide from the substrate surface. An Sb2Te3 seed layer was grown initially at room temperature followed by alternate deposition of GeTe and Sb2Te3 layers at high temperature.
The crystal structure of the films as well as the degree of orientation were evaluated by x-ray diffraction (XRD) while the microstructure was observed by transmission electron microscopy (TEM). We found there is a strong dependency on substrate materials in terms of out-of-plane orientation of the superlattice film. On the basis of the obtained results, we will discuss the growth mechanisms of layered chalcogenide films and propose optimal growth conditions for future phase change memory applications.
This work was supported by JST-CREST (JPMJCR14F1).
(Keynote) MnPO4-Coating for Improved Long-Term Performance of Li(Ni0.4Co0.2Mn0.4)O2 in Ionic Liquid-Based Electrolytes
Authors: Chen Zhen , Kim Guk-Tae , Bresser Dominic , Jeong Sangsik , Copley Mark , Lin Janyi , Shen Zexiang , Passerini Stefano 
Published: February 2020

MnPO4-coated LiNi0.4Co0.2Mn0.4O2 (MP-NCM) [1] is demonstrated to be a high performance lithium battery cathode material in combination with the room-temperature ionic liquid-based electrolyte consisting of LiTFSI-PYR14FSI (2:8 molar ratio). The MnPO4 coating acts as an ideal protective layer to physically prevent the contact between the NCM active material and the electrolyte, thus, successfully stabilizing the electrode/electrolyte interface and preventing detrimental side reactions even in conventional, carbonate-based electrolytes [2]. As a result, MP-NCM-based electrodes reveal greatly enhanced C rate capability and cycling stability – even under extreme conditions like extended operational potential windows, elevated temperature, and higher active material mass loadings. Employing an ionic liquid-based electrolyte allows for outstanding cycling stability of lab-scale pouch cells, offering a capacity retention of well above 85% after 2000 cycles. The superior electrochemical behavior of MP-NCM compared to as-synthesized NCM is assigned to the superior stability of the electrode/electrolyte interface and structural integrity when applying a MnPO4 coating, rendering this approach highly promising also for other state-of-the-art and next generation lithium battery cathodes.
References
[1] Z. Chen, D. Chao, J. Liu, M. Copley, J. Lin, Z. Shen, G.-T. Kim, S. Passerini, J. Mater. Chem. A, 5, 2017, 15669
[2] Z. Chen, G.-T. Kim, D. Bresser, T. Diemant, S. Jeong, M Copley, R. J. Behm, J. Lin, Z. Shen, Stefano Passerini, Energy & Environmental Science (2018) submitted
Development of Utility Friendly Olivine Based ESS in Esstalion Technologies – Part-2
Authors: Asakawa Yuichiro , Daigle Jean-Christophe , Zaghib Karim , Ueno Hiroshi 
Published: February 2020

One of the promising approaches for striking a balance of realizing sustainable society and maximizing utility’s profit is to apply energy storage system (ESS). There’re many use cases proposed (1), such as reserve, regulation, peak shaving, time shift, load following, and renewable integration. To answer these demands, the development of a battery with high rate of charging and discharging, a longer cycle life and safe is imperative.
Esstalion Technologies Inc. has developed LFP LTO technologies with outstanding long life and excellent low temperature performance. (2) It is well know that material stability of LFP and LTO is key to those properties (3), however highly reactive surface of LTO causes undesirable reactions such as gas evolution (4). Those degradation modes hold back the possibilities of full utilization of material stability of LFP and LTO. We investigated mechanisms of failure modes at cathode and anode interfaces. Based the mechanisms, we overcome the issues, and found unique interface structure realizes the properties of our LFP LTO technology.
We propose a brief review of our technologies and we will show an example of our efforts to enhance the key properties of the Li-ion battery.
References
(1) Pacific Northwest National Laboratory, Protocol for Uniformly Measuring and Expressing the Performance of Energy Storage Systems
(2) Y. Asakawa et al., ECS Abstract MA2017-02 112
(3) K. Zaghib, M. Dontigny, A. Guerfi, P. Charest, I. Rodrigues, A. Mauger,
C.M. Julien, J. Power Sources 196 (8) (2011) 3949e3954.
(4) I. Belharouak et al., J. Electrochem. Soc. 2012 volume 159, issue 8, A1165-A1170
(Keynote) Ionic Liquid Electrolytes and Ionogel Composites that Enable High Capacity Anodes for Lithium and Sodium Batteries
Authors: Forsyth Maria , Howlett Patrick C , MacFarlane Douglas R. , Mecerreyes David , Girard Gaetan , Yunis Ruhamah , Armand Michel , Wang Xiaoen 
Published: February 2020

With accelerating growth in demand for longer lasting, more durable and safer rechargeable energy storage technologies, it has become clear that we must find solutions to deliver these features while also using higher energy-density electrodes. As an anode material, graphite is limited in achieving high capacities due to its relatively low specific capacity of 372mAh/g. Li metal presents as an attractive alternative due to a ten-fold increase in specific capacity (3862mAh/g), while Na metal is nearly four times greater at 1166mAh/g. Electrolytes currently used for Li-ion and Na-ion devices are not compatible with these higher energy-density anodes. Instead we show that by using an ultra-high concentration of lithium or sodium salt in an ionic liquid we can facilitate stable cycling of Li metal and Na metal anodes, often at high rates and current densities, and even in the presence of water. These electrolytes indicate a decoupling of the alkali metal ion dynamics from the bulk with tLi+ or tNa+ transport numbers approaching 0.5. We will discuss the structure and transport in these superconcentrated IL systems and the importance of clustering and structural rearrangement in the transport mechanism of the alkali metal cation.
Polymerized ionic liquids, such as poly(diallyldimethylammonium) (PDADMA), with either TFSI or FSI counterions, are capable of dissolving even higher concentrations of lithium salt leading to highly conductive solid electrolytes. These materials have high tLi+ and improved mechanical properties and also enable stable Li metal cycling, thus offering exciting opportunities for all solid state lithium batteries. Interestingly, the nature of the counterion associated with the PIL has a significant impact on the compatibility with the IL electrolytes and on the resultant conductivity and mechanical properties. These materials will be discussed in terms of their phase behavior, conductivity and electrochemical behavior.
(Keynote) Redox-Active Polymeric Electrodes and Polymer Electrolytes
Authors: Sánchez Fontecoba Paula , Zhang Heng , Armand Michel , Rojo Teófilo 
Published: February 2020

Electrochemical energy storage is one of the main societal challenges to human kind in this century. Among the myriad of energy-storage technologies, rechargeable batteries play a pivotal role because of their high specific energy and energy density. [1]
The evolution and development of rechargeable batteries have been tightly bonded to the research of polymeric materials, such as polymeric electrodes, polymer electrolytes, separators, binders, and so on. In particular, polymeric redox-active electrodes and polymer electrolytes have been emerging as promising candidates to substitute inorganic electrode materials and liquid electrolytes, respectively. This is because of the low cost of the precursors and the sustainability of their synthetic methods. Moreover, for polymeric materials, the existence of such a vast range of possible structures enables the proper tuning of structure-related properties according to the different requirements.
In the last few years, we have devoted continuous efforts on the research of polymeric redox-active electrodes and polymer electrolytes. We have conceived several novel concepts in these fields. In this talk, we will present an overview the development and our latest results on the polymeric redox-active electrodes, especially the family of poly-Schiff base/oligoether terpolymers. [2-4] In addition, highly conductive polymer electrolyte comprised of Jeffamine-based polymer matrices, [5] single ion conducting polysalts, [6] composite/hybrid solid polymer electrolytes, [7,8] novel additives for solid polymer electrolytes [9] will be also presented.

References

[1] M. Armand, and J.-M. Tarascon. Nature, 2008, 451, 652.
[2] M. López-Herraiz, E. Castillo-Martínez, J. Carretero-González, J. Carrasco, T. Rojo and M. Armand, Energy Environ. Sci., 2015, 8, 3233.
[3] E. Castillo-Martínez, J. Carretero-González, and M. Armand, Angew. Chem Int. Ed.,
2014, 53, 5341.
[4] N. Fernández, P. Sánchez-Fontecoba, E. Castillo-Martínez, J. Carretero-González, T. Rojo and M. Armand, ChemSusChem,
2018, 11, 311-319.
[5] I. Aldalur, H. Zhang, M. Piszcz, U. Oteo, L.M. Rodriguez-Martinez, D. Shanmukaraj, T. Rojo, and M. Armand, J. Power Sources, 2017, 347, 37.
[6] H. Zhang, C. Li, M. Piszcz, E. Coya, T. Rojo, L.M. Rodriguez-Martinez, M. Armand, and Z. Zhou, Chem. Soc. Rev., 46, 2017, 797.
[7] X. Judez, H. Zhang, C. Li, G.G. Eshetu, Y. Zhang, J.A. González-Marcos, M. Armand, and L.M. Rodriguez-Martinez, J. Phys.
Chem. Lett.,
2017, 8, 3473.
[8] N. Lago, O. Garcia-Calvo, J.M. Lopez del Amo, T. Rojo, M. Armand, ChemSusChem, 2015, 8, 3039.
[9] G.G. Eshetu, X. Judez, C. Li, O. Bondarchuk, L.M. Rodriguez-Martinez, H. Zhang, and M. Armand, Angew. Chem Int. Ed.,
2017, 56, 15368.
(Keynote) Redox-Active Organic Species for Rechargeable Batteries, and Beyond!
Authors: Poizot Philippe , Jouhara Alia , Deunf Elise , Dupré Nicolas , Guyomard Dominique , Dolhem Franck 
Published: February 2020

Our entry into the Fourth industrial revolution since the turn of the century is set to revolutionize our daily life notably with the blooming of digital technologies such as communications, artificial intelligence, technologies related to the Internet of Things (IoT), 3-D printing or nano/bio-technologies. It is however hoped this new paradigm shift will integrate sustainable development goals and actions to address the critical damage caused by the previous industrial revolutions especially the threat of global warming. We have to be particularly aware there remains the urgent need for cleaner energy technologies which calls for a radical change in the energy mix to favour renewable energy and environmentally responsible energy storage solutions. To date, commercial batteries exclusively include inorganic electrode materials notably 3d transition-metals which are scarce, expensive and energy-greedy. In contrast, organic materials enable access to low cost and possibly greener compounds because composed of naturally abundant elements (i.e., C, H, O, N or S) moreover they are easier to recycle. In addition, they offer high structural designability through the well-established principles of organic chemistry and notably access to both n- and p-type electrochemical storage mechanisms making various cell or electrode configurations possible (Figure 1).
In 10 years, tremendous progress has been made to promote organic compounds in various rechargeable storage devices giving rise to nearly 15 published review articles especially for applications in non-aqueous (metallic) Li or Na-based batteries. However, several improvements are needed to further promote insertion organic electrode materials. For instance, only few studies have been reported in the literature regarding the assembly of full Li-ion organic cells while the literature is quite abundant in terms of Li metal-organic batteries; the main difficulty being to successfully synthesize robust lithiated cathode materials.
This contribution aims at reporting recent electrochemical data obtained with crystallized organic materials and explaining how it is possible to tune the electrochemical activity towards higher voltages depending on the molecular assembly and its electrostatic environment in Li enolate-based organic cathodes. In addition, a specific electrochemical study using soluble redox-active organic species will be reported providing to the Li battery community a supplementary proof concerning the high reactivity of the most popular supporting salt (i.e., LiPF6) versus any labile proton potentially present in a battery electrolyte.

Figure 1
A High-Voltage Aqueous Electrolyte for Sodium-Ion Batteries
Authors: Kühnel Ruben-Simon , Reber David , Battaglia Corsin 
Published: February 2020

Aqueous sodium-ion batteries promise increased operational safety and lower cost compared to current state-of-the-art lithium-ion batteries based on organic electrolytes. For large-scale stationary systems, which find increasing application in the grid integration of electricity generated from intermittent renewable sources, these advantages of aqueous electrolyte batteries could translate into lower total-cost-of-ownership compared to organic electrolyte batteries. The major disadvantage of water as electrolyte solvent for batteries is its intrinsically narrow electrochemical stability window (thermodynamically only 1.23 V) limiting maximum cell voltage and consequently the battery’s energy density. We recently discovered an aqueous sodium-ion electrolyte system with a much enhanced electrochemical stability window. The wide stability window of 2.6 V for 35m aqueous NaFSI solutions broadens the choice of suitable active materials for aqueous sodium-ion batteries. We demonstrate stable cycling of a NaTi2(PO4)3 anode and a Na3(VOPO4)2F cathode in this aqueous electrolyte enabling the fabrication of high-voltage rechargeable aqueous sodium-ion batteries and discuss route to further increase the cell voltage.
R.-S. Kühnel, D. Reber, C. Battaglia, ACS Energy Letters 2017, 2, 2005
(Invited) Design, Analysis and Understanding of Electrochemical Interfaces for Energy Storage and Conversion
Authors: Strasser Peter 
Published: February 2020

Electrochemistry and electrocatalysis play prominent roles in the science and technology of renewable electrical energy storage and conversion. Storage and conversion is put into effect via molecular bond making and breaking, catalyzed at electrified interfaces of an ion conductor and an electrocatalyst inside electrochemical reactors, such as Fuel Cells or Electrolyzers. For these reactions to occur with the smallest possible energy losses and the utmost atom efficiency, nanostructured multi-component electrode materials have proven indispensable, because they offer substantial advantages in atomic dispersion, often resulting in energy efficiency and performance benefits. What is more, electrocatalyst always undergo initial transient structural reorganization before their reactivity can fully unfold.
The successful development of novel nanostructured electrocatalyst materials requires molecular insights into their initial structural evolution (activation behaviour, active site/phase formation) as well as the relation between their atomic-scale structure and their catalytic performance. Unravelling these insights and relations is thus a scientific priority.
In this talk, I will highlight some of our recent work on the design and analysis of nanostructured electrocatalytic materials and their catalytically active liquid-solid interfaces. Examples will include new designs of and insights in noble and non-noble water splitting catalysts, oxygen reduction catalysts as well as CO2 reduction catalysts.
Electrochemical Synthesis of Cu-Cu2o-CNT/CNF Composite Coatings
Authors: Mech Krzysztof , Szacilowski Konrad 
Published: February 2020

The main scientific objective of performed studies was development of methodology for electrochemical synthesis of ternary composite materials in the Cu-Cu2O-CNT/CNF systems (CNT – carbon nanotubes, CNF – carbon nanofibers). Copper is the only metal that exhibits very high selectivity for electrochemical conversion of CO2 to ethylene (1). Ren et al. observed similar effect in case of p-type Cu2O (2). Reported effects allows on assumption that combination of both materials can be great solution in the frame of light supported electrochemical conversion of carbon dioxide to ethylene. Additionally application of carbon structures: CNT or CNF as charge transfer mediators can limit photodegradation of Cu2O, improving simultaneously its chemical stability (3) and catalytic activity as well as selectivity for electrochemical conversion of CO2 to ethylene (2). Presence of highly hydrophobic CNT/CNF phase in Cu matrix may significantly improve selectivity through limiting adsorption of polar water molecules favoring simultaneously adsorption of nonpolar CO2 molecules.
Present studies describing optimization of electrochemical synthesis process towards synthesis of composite coatings of wide composition range. Synthesis conditions were investigated starting from thermodynamic analysis of the electrolyte. In next step, based on zeta potentials values stability of colloidal electrolyte containing carbon nanotubes was analyzed. Current-voltage conditions allowing on deposition of Cu with Cu2O with simultaneous incorporation of CNT/CNF structures were determined based on voltammetric and elctrogravimetric tests. Synthesized coatings were characterized towards their composition, structure and morphology.
References

Y. Kwon, Y. Lum, E. L. Clark, J. W. Ager and A. T. Bell, ChemElectroChem, 3, 1012 (2016).

D. Ren, Y. Deng, A. D. Handoko, C. S. Chen, S. Malkhandi and B. S. Yeo, ACS Catalysis, 5, 2814 (2015).

P. D. Tran, S. K. Batabyal, S. S. Pramana, J. Barber, L. H. Wong and S. C. J. Loo, Nanoscale, 4, 3875 (2012).
Preparation of n-MoS2 for HER Using a High Voltage Electrochemical Deposition Method
Authors: Kim Seong-Hoon , Iqbal Muhammad Ibrahim , Abbas Syed Asad , Jung Kwang-Deog 
Published: February 2020

Recently, MoS2 has attracted attention as a HER (hydrogen evolution reaction) catalyst for replacing Pt, because it has similar hydrogen bonidng energy to Pt. Here, a HVER (high-voltage electrochemical reduction) method in a H-cell was attempted to prepare nanosized MoS2 on graphene. A Pt wire was used as a cathode to reduce (NH4)2MoS4 to MoS2 on the graphene particles dispersed in water and a potential of 60 V was applied to the cell and a varible resistor was adjusted to allow a current of 50 mA to flow. During the electrochemical reduction, no Mo deposition on the Pt cathode was observed and MoS2/graphene particles were simply obtained with a short preparation time of less than 15 min. Fig.1 shows LSV of MoS2/rGO synthesized at the diffierent reduction time with a RDE and EIS Nyquist plots corresponding to the LSV. The MoS2/rGO sample prepared at the reduction time of 10 min exhibited the highest current density of 37.6 mA/cm2 at the overpotential of 200 mV. EIS analysis showed that the MoS2/rGO sample (10 min) has the lowest charge transfer resistance of 25 Ω. Particle sizes of the prepared MoS2 were observed with TEM analysis. The particle size of MoS2 (10 min) was in the range of 4-10 nm. The particle size of MoS2 increased with increasing the electroreduction time. It was reported that the smaller the particle size of MoS2, the higher the HER activity.1) So, one reason for the decrease in the activity of the sample prepared at a reduction time of more than 10 minutes is because the particle size of MoS2 increases as the electrochemical reduction time increases. XRD diffraction patterns of the prepared samples showed that the prepared MoS2 samples had three phase of 1T (tegragonal), 2H (hexagonal) and 3R (rhombohedral) and the 3R phase was mainly observed. The MoS2 has been prepared in a hydrothermal method for HER, which shows mainly 2H phase. Recently, it was suggested that 3R phase of MoS2 outperformed the corresponding 2H phase for hydrogen evolution.2) In that aspect, it is proposed that the HVER method is a promising technique for producing high activity MoS2 catalysts.
References
[1] L. Lei, Z. Jie, B. Xiaojun, Z. Lina, D. Micheal, G.H. Scanlon, L. Baohong, Adv. Funct. Mater., 23, 5326 (2013). [2] T.J. Rou, S. Zdenek, L. Jan, S. David, P. Martin, ChemComm, 53, 3054 (2017)

Figure 1
Pulse Electrodeposition of Copper Octahedrons: Investigations into the CO2RR on These Surfaces
Authors: Rashid Nusrat , Ingole Pravin popinand 
Published: February 2020

A well-tamed energy conversion strategy for the valorization of CO2 is a necessity for maintaining a check on CO2 levels (~ 500ppm) and borrow enough time for the scientific community to perfect zero-emission fuel prospects. Mimicking photosynthetically fixed CO2 by plants in an electrochemical cell is both scientifically intriguing and sociologically promising- given more than half of world still runs on fossil fuel derived energy and standard of life are determined by the intake of energy. Catalysing CO2RR with economical, selective heterogeneous metal nano-structures proved a promising way to improve upon the status quo.
We synthesised copper octahedrons by two electrode electrodeposition, to selectively reduce CO2RR into CO2+H2 (synthesis gas) to use it as starting material in well known Fischer-tropsch reaction. In a representative experiment, copper was dissolved from a sacrificial copper anode and collected as micro-octahedrons on the surface of a platinum foil. The structures were simply tapped off the surface, cleaned, dried and used as catalyst ink to reduce CO2 into value-added fuels. A set of experimental parameters were varied to study the effect of them on morphology, size and activity of the obtained copper powders. A pulse method involving anodic and cathodic waves passed through the copper anode was found to have a determining capability - be it shape, topology or size of the crystallites.
In a catholyte composed of 0.2 M KHCO3, cyclo-voltammograms (CVs) were recorded in N2 saturated and CO2 catholyte in a 3-electrode, 2-chambered cell. From preliminary results, it was shown that CuOcta showed activity towards CO2RR as was evident in enhanced faradaic response in CO2 saturated catholyte. To confirm the path of fixing and valorization, a thorough gas chromatography (GC) analysis was done on the gases that were collected in a Tedlar bag. CO was found to be major reduction product in gaseous phase overcoming the inherit HER (hydrogen evolution reaction) competition on metal surfaces. A significant amount of CH4 was also measured. The array of obtained products signal role of morphology, the surface topography of catalytic structures on the mechanism and kinetics of CO2RR.

Figure 1