bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(fluorene phenylene) Graft Copolymer As a Novel Binder with Polyvinylpyrrolidone for High-Capacity Silicon Anode in Lithium-Ion Batteries
Authors: Avci Ipek , Taskin Omer Suat , Yuca Neslihan , Cetintasoglu Mehmet Emre , Doğdu Murat Ferhat 
Published: February 2020

Rechargeable lithium ion batteries (LIB) have been vastly used in portable devices like cellular phones, laptops, tablets and also in electric vehicles because of their relatively high energy density, good power performance and cycle life. Carbonaceous negative electrode materials, especially graphitic carbons are conventionally used as anode materials at LIBs due to their good cycle-ability and low stable discharge voltage plateau. However, graphite has a low Li atomic density at full Li capacity in carbon intercalation compound (LiC6) which leads to lower theoretical capacity (372 mAh/g). Therefore, different types of anode active materials have been investigated as an alternative to graphite in order to achieve higher capacities. Among them, silicon (Si) is one of the most promising candidate as an anode active material because of its high theoretical capacity (more than 3500 mAh/g at room temperature) and low average discharge potential (∼0.5 V vs Li/Li+).Unfortunately, huge volume expansion (310% at full lithiation of Si) due to the lithium ion diffusion during the lithiation/delithiation process causes drastic capacity fade because of the high internal stresses, loss of electrical contact and the formation of non-electronic and ionic conductive passivation film between the anode surface and electrolyte. Low electrical conductivity of silicon is also another problem that remarkably hinders the rate performance.
In the present work, above mentioned shortcomings are overwhelmed by incorporating tri(ethylene glycol) (TEG) groups over phenylene base units as side chains on the framework of the PFP based conductive polymer. Polyvinylpyrrolidone (PVP) was also used as adhesive to enhance the property of binding, thus decreasing stress-induced cracks. The synthesis was achieved through Suzuki polycondensation reaction in the presence of Pd(PPh3)4 catalyst by using independently prepared TEG functionalized dibromo benzene in conjunction with dioctylfluorene-diboronic acid bis(1,3-propanediol) ester. The obtained conductive and flexible polymer was used as a binder for Si-anode with high performance. It was demonstrated that the designed and fabricated binder polymer with multi-functionality displays a high electronic conductivity, mechanical strength, high polarity, adhesion, and more importantly, the electrolyte uptake arising from its excellent ductility.

Figure 1
(Invited) Realizing 2D Materials Via MOCVD
Authors: Briggs Natalie , Subramanian Shruti , Lin Yu-Chuan , Eichfeld Sarah , Jariwala Bhakti , Bhimanapati Ganesh , Zhang Kehao , Robinson Joshua A 
Published: February 2020

The last decade has seen nearly exponential growth in the science and technology of two-dimensional materials. Beyond graphene, there is a huge variety of layered materials that range in properties from insulating to superconducting. Furthermore, heterogeneous stacking of 2D materials also allows for additional “dimensionality” for band structure engineering. In this talk, I will discuss recent breakthroughs in two-dimensional atomic layer synthesis and properties, including novel 2D heterostructures and novel 2D nitrides. Our recent works include development of an understanding of substrate impact on 2D layer growth and properties, doping of 2D materials with magentic elements, selective area synthesis of 2D materials, and the first demonstration of 2D gallium nitride (2D-GaN). Our work and the work of our collaborators has lead to a better understanding of how substrate not only impacts 2D crystal quality, but also doping efficiency in 2D materials, and stabalization of nitrides at their quantum limit.

Z.Y. Al Balushi, K.Wang, R.Krishna Ghosh, R.A. Vilá, S.M. Eichfeld, P.A. DeSario, D.F. Paul, J.D. Caldwell, S.Datta, J.M. Redwing, J.A. Robinson; Graphene stabilization of two-dimensional gallium nitride; arXiv preprint:1511.01871

Eichfeld, S. M.; Hossain, L.; Lin, Y.-C.; Piasecki, A. F.; Kupp, B.; Birdwell, A. G. G.; Burke, R. A.; Lu, N.; Peng, X.; Li, J.; et al. Highly Scalable, Atomically Thin WSe2 Grown via Metal-Organic Chemical Vapor Deposition. ACS Nano 2015.

Y.C. Lin, C.-Y. Chang, R. Ghosh,J.Li, H.Zhu, R.Addou, B.Diaconescu, T.Ohta, X.Peng, N.Lu, M.J. Kim, J.T. Robinson, R.M.Wallace, T.Mayer, S.Datta, L.J. Li, J.A. Robinson; Atomically Thin Heterostructures based on Single-Layer Tungsten Diselenide and Graphene; Nano Letters

M. S. Bresnehan, G. Bhimanapati, K. Wang, D.Snyder, J.A.Robinson; Impact of Copper Overpressure on the Synthesis of Hexagonal Boron Nitride Atomic Layers; ACS Appl. Mater. Interfaces, 6, 16755–16762 (2014)

S.M. Eichfeld, C.M. Eichfeld, Y.C. Lin, L. Hossain, J.A. Robinson; Rapid, non-destructive evaluation of ultrathin WSe2 using spectroscopic ellipsometry; APL Materials 2 (9), 092508

Y.C. Lin, N. Lu, N. Perea-Lopez, J. Li, C.H. Lee, Z.Lin, P.N. Browning, M.S. Bresnehan, L. Calderin, M.J. Kim, T.S. Mayer, M. Terrones, J.A. Robinson; Direct Synthesis of van der Waals Solids on Epitaxial Graphene; ACS Nano 8 (4), 3715-3723 (2014)
(Invited) The Structure-Dependent Properties of InAs Nanowires and Their Devices
Authors: Fu Mengqi , Shi Tuanwei , Li Xing , Chen Qing 
Published: February 2020

InAs nanowire is an important III-V group semiconducting nanomaterial with direct and narrow bandgap and small effective electron mass. It has great potential in high-performance electronic nanodevices and infrared detectors. In this talk, I will introduce our recent progresses on the structure-dependent properties of InAs nanowires and their devices.
Various properties of individual InAs nanowires are studied and correlated with their structures through a comprehensive in situ platform we have developed in a scanning electron microscope. Remarkable piezoelectric and piezoresistive effects are observed for the first time in single-crystalline <0001> WZ InAs nanowires, but negligible effect is found in WZ nanowires with other orientations and nanowires with ZB structures. An ultrafast and reversible electrochemical lithiation of InAs nanowires are observed for the first time.
Field effect transistors (FETs) based on MBE-grown InAs nanowires are studied. Importantly, based on nano-manipulation and microlithography, we develop a new method to characterize the same individual InAs nanowires in the FETs by transmission electron microscopy to obtain the atomic-level structures. Our study shows that not only the diameter, but also the crystal structure and the orientation of the InAs nanowires remarkably affect the electronic properties of the FETs, such as the threshold voltage, On/OFF current ratio, on-state current, subthreshold swing and electron mobility, etc. Ohmic contact are obtained for the nanowires with different diameters down to 7 nm.
RAMAN Characterization of Ge1-XSnX Allows By Using a SPACE Correlation MODEL
Authors: Pérez Ladrón de Guevara Héctor , Vidal Borbolla Miguel Angel , Rodriguez Vazquez Angel Gabriel , Navarro Contreras Hugo Ricardo 
Published: February 2020

Ge1-xSnx alloys present important optoelectronic properties due to the possibility for obtain a direct and tunable energy gap group IV semiconductor. Ge1-xSnx alloys were grown on different substrates by using a R. F. Magnetron Sputtering. Raman spectroscopy and HRXRD were used in order to determinate the structural properties of these alloys. We determined a linear shift of the Raman peak that depends directly on the Sn concentration of the alloy. We also find that the Raman peak has an asymmetrical shape attributed to a small crystal size. In this work we present the characterization of the Raman peaks by fitting a Space Correlation Model. We obtain a strong correlation among FWHM, asymmetrical shape and Sn concentration of the alloys.
Keywords: HRXRD, Raman.
(Invited) Finely Controlled Heterointerfaces between Ge(111) and Metallic Alloys or Insulators for Next Generation Ge-Based Devices
Authors: Hamaya Kohei , Yamada Shinya , Kasahara Kenji , Kanashima Takeshi 
Published: February 2020

For next generation Ge-based devices, we have developed epitaxial growth techniques of high-performance ferromagnetic alloys or high-k insulators on Ge(111). By using low-temperature MBE or PLD, high-quality heterointerfaces for source/drain or gate-stack structures can be achieved, respectively. We detect spin transport in n-Ge(111) and p-Ge(111) through the high-quality ferromagnetic alloys/Ge(111). In addition, the Fermi level pinning is markedly suppressed even for the metal/Ge contacts and the Schottky barrier height of the metal/p-Ge contacts can be controlled by the metal work function. Finally, we show a new approach for gate-stack structures with crystalline high-k La2O3 layers. We obtained atomically smooth heterointerfaces between La2O3 and Ge(111). These results will open a road to integrate finely controlled structures into next generation Ge devices.
Steps Towards Reactive Hydrogen Pumping
Authors: Fane Brian , Goenaga Gabriel A. , Zawodzinski Thomas A. 
Published: February 2020

Polymer electrolyte membrane (PEM) fuel cells are an attractive energy conversion device because of the potential for extremely high efficiency and low emissions. Pure hydrogen is an ideal fuel for PEM fuel cells but it is energy intensive to produce. Currently, the main method of producing hydrogen is steam reforming of natural gas. This is a break from the renewable energy future promised by hydrogen fuel cells. A greener approach to producing hydrogen is electrochemical reforming, the most obvious feedstock is water. Water electrolysis occurs at a relatively high potential (1.23 V), which makes it expensive both in terms of materials required and electricity. To fulfill the promise of fuel cells, more efficient methods of producing hydrogen must be found.
One way to reduce the energy required is to depolarize the PEM electrolyzer anode by using an alternate feed. This feed must have a lower oxidation potential than water and be generated renewably. Two alternative feeds we have looked at are methanol and phosphomolybdic acid.
Oxidation of methanol-water solutions to hydrogen takes place at a theoretical voltage of 0.03 V. Methanol fuel cells are a well-studied problem and the issues are known. The main issue is crossover of methanol to the cathode, lowering the total cell potential. We looked to see if this would be as problematic in a hydrogen pumping environment since there would be no oxygen at the cathode for the methanol to react with.
The other feed we examined was phosphomolybdic acid (PMA). PMA is a keggin ion which is readily reduced by biomass substrates in the presence of sunlight or heat.1Our idea was to apply the concept of a depolarized anode electrolyzer to a mediated electrochemical system. This system has the PMA in solution as a combination catalyst and charge carrier. The PMA is reduced by biomass and circulated to an anode where it is oxidized to release the hydrogen removed from the biomass. This gives many of the advantages of a flow battery, where power and capacity scale separately. Our focus has been on studying the anode performance characteristics of PMA.
References.
1. Liu W, Mu W, Liu M, Zhang X, Cai H, Deng Y. Solar-induced direct biomass-to-electricity hybrid fuel cell using polyoxometalates as photocatalyst and charge carrier. Nat Commun. 2014;5:3208. doi:10.1038/ncomms4208.
Spectrometric Quantification of the Rate of Carbon Corrosion on Oxygen Evolving Electrodes in Alkaline Media
Authors: Uddin Jasim , Tan Hongjin , Giordani Vincent , Chase Gregory V , Addison Dan 
Published: February 2020

Carbon-based electrodes are known to undergo corrosion in acidic and alkaline media during the oxygen evolution reaction (OER), yet studies on the efficacy of OER catalysts frequently employ carbon as catalyst support. Carbon remains a material of interest in the development of bifunctional air electrodes, particularly due to its utility in supporting efficient oxygen reduction reaction (ORR) catalysis. Methods to quantify carbon corrosion rates are needed in order to assess the practical utility of carbonaceous materials in bifunctional air electrodes and other OER electrodes. In-situ electrochemical mass spectrometry enables direct and precise assessment of carbon corrosion in acidic media by quantifying gaseous CO2 that is generated as a product of the corrosion reaction. For alkaline media, this in-situ approach is unsuitable since CO2 generated during corrosion reacts with and is sequestered within the alkaline electrolyte as carbonate.
In this presentation, we describe a method to precisely quantify carbon corrosion in alkaline media. The method is direct and sufficiently sensitive to provide rapid (1-2 days) characterization of carbon corrosion, whereas methods based on electrochemical characterization or mass measurement may yield ambiguous results and take months. We report on the use of this method to quantitatively compare the rate of corrosion using different types of carbon, including reduced graphene oxide, doped carbon and carbons with various coatings and catalysts. A critical assessment of the use of carbon in bifunctional air electrodes will be provided.
Effect of Bulky Cations on the Stability and Properties of Anion Exchange Membranes
Authors: Liu Ye , Yuan Haomiao , Wang Junhua , Zhang Bingzi , Coughlin Bryan E , Yan Yushan , Liberatore Matthew W , Herring Andrew M 
Published: February 2020

Alkaline anion exchange membrane fuel cells are widely investigated recently as promising alternative to well-established proton exchange membrane fuel cells. Anion exchange membranes, using as solid electrolytes, are required to be thermally, chemically and mechanically stable in base at the operation temperature and humidity, as well as have an efficient OH- transport along the membrane across two electrodes.
This study aims at studying AEMs functionalized with three different bulky cations. They are 1,4,5-trimethyl-2-(2,4,6-trimethoxyphenyl) imidazolium functionalized polyphenylene oxide (Figure 1(a)) [1], tris(2,4,6-trimethoxyphenyl) phosphonium functionalized PPO (Figure 1(b)) [2], and phenylene cobaltocenium functionalized norbornene (Figure 1(c)).
Degradation study on 1,4,5-trimethyl-2-(2,4,6-trimethoxyphenyl) imidazolium functionalize PPO and unsubstituted imidazolium PPO by soaking both two membranes into 1 M sodium hydroxide at 80°C indicates attachment of 2,4,6-trimethoxyphenyl group efficiently improve OH- stability due to the enhanced volumetric steric and basicity of the central cation. Super hydrophobic and bulky phosphonium cation attached by three 2,4,6-trimethoxyphenyl groups has the chemical stability surpassing benzyl trimethyl ammonium by 30% after degrading in 1 M KOH at 80°C for 20 days. The cobaltocenium cation, which has 18 valance electrons further improve the chemical stability by 60% higher than trimethyl ammonium after treating in 1 M NaOH/CH3OH at 80°C for 20 days (Figure 2).
Besides enhanced chemical properties from these bulky cations, their influence on the other polymer properties include thermal stability, water uptake, conductivity as well as transport property are also discussed.
Figure 1. Structure of 1,4,5-trimethyl-2-(2,4,6-trimethoxyphenyl) imidazolium functionalized PPO (a), tris(2,4,6-trimethoxyphenyl) phosphonium functionalized PPO (b) and phenylene cobaltocenium functionalized norbornene (c).
Figure 2. Degradation studies performed at 80°C on 1,4,5-trimethyl-2-(2,4,6-trimethoxyphenyl) imidazolium (solid diamond, 1 M KOH), tris(2,4,6-trimethoxyphenyl) phosphonium (solid square, 1 M KOH), phenylene cobaltocenium (solid triangle, 1 M NaOH/CH3OH) and benzyl trimethyl ammonium (open square, 1 M KOH; open triangle, 1 M NaOH/CH3OH).
Reference
[1] Y. Liu, J. Wang, Y. Yang, T.M. Brenner, S. Seifert, Y. Yan, M.W. Liberatore, A.M. Herring, J. Phys. Chem. C 118 (2014) 15136-15145.
[2] Y. Liu, B. Zhang, C.L. Kinsinger, Y. Yang, S. Seifert, Y. Yan, C.M. Maupin, M.W. Liberatore, A.M. Herring, J. Membr. Sci. 506 (2016) 50-59.

Figure 1
Preparation and Characterization of Cgo-Based Catalyst for Methanol Steam Reforming By Glycine-Nitrate Process
Authors: Lee Junghun , Choi Eunyeong , Ji Hyunjin 
Published: February 2020

Methanol is a liquid fuel which can be produced from renewable energy sources and has high energy density. It has a low boiling point, a high H:C ratio of 4:1 without any C-C bond, therefore can be reformated at a relatively low temperature. In this work, we investigated the application of CGO(Gd:CeO2)-based catalyst for hydrogen production via methanol steam reforming. CGO-based powder material for a catalyst of methanol steam reforming was synthesized by glycine-nitrate process(GNP). GNP is one of the solution combustion synthesis methods, Metal nitrate and glycine were mixed with deionized water and solution heated by hot plate. After evaporation of water, solution converted to a viscous gel. The gel ignited with gases and powders. The synthesized powders were calcined for 4 hours at 800°C to remove moisture and impurity. Their properties such as micro structure, surface morphology, surface area and composition were investigated with XRD(X-ray diffraction), SEM(Scanning electron microscopy), BET (N2 adsorption-desorption), EDS(Energy dispersive spectroscopy) and ICP-MS(Inductively coupled plasma mass spectrometry). The performance of catalysts was examined with reactor at 200 - 400°C range. The reactants and reaction products were analyzed by GC(Gas chromatography). The catalytic performance for hydrogen production was analyzed in terms of methanol conversion and selectivity of products.
Cathode Catalyst Layer Design and Optimization for Portable Power Applications Using Non-Precious Metal Catalysts
Authors: Kishimoto Takeaki , Sato Tetsutaro , Kobayashi Yoshikazu , Narizuka Kumi , Banham Dustin , Zhou Yingjie , Marquez Emil , Bai Kyoung , Ye Siyu 
Published: February 2020

In recent years, the inherent activity of M/N/C (M=Fe, Co, or Mn) non precious metal catalyst (NPMCs) has advanced to a stage where these catalysts can be considered as potential alternatives to Pt/Pt-alloy catalysts for certain applications(1-4), provided stability/durability can be improved(5). Due to these achievements, NPMCs have advanced beyond purely rotating disc electrode (RDE) studies, and are now ready to be thoroughly evaluated at the membrane electrode assembly (MEA) level. While previous work has looked at in-situ MEA evaluation of NPMCs, few of these studies have investigated maximizing performance through rational design of the cathode catalyst layer (CCL). However, recent work by Serov et al. (3) has highlighted the importance of CCL design parameters in maximizing the performance of NPMC-based CCLs.
The significant difference in CCL layer thickness of NPMC-based CCLs vs. conventional Pt/C CCLs means any optimization used for conventional Pt/C CCLs will likely not apply to these novel NPMC CCLs. This provides the research community with significant opportunity in this largely unexplored area.
In this work, we will present some of our recent findings on designing and optimizing NPMC-based CCLs for portable power and backup power applications. The NPMC used in this work is developed by Nisshinbo Holdings, and has demonstrated world-leading performance in laboratory scale (50 cm2) MEA testing. After a brief discussion on the synthesis of this NPMC, the results of optimizing the CCL design (e.g. ionomer type/content) will be shown. Performance data recently obtained under conditions relevant for portable power/backup power will be presented and compared against product requirements.

Acknowledgements

The authors thank Alan Young for many helpful discussions,

References

1. M. Lefèvre, E. Proietti, F. Jaouen and J.-P. Dodelet, Science, 324, 71 (2009).
2. F. J. Eric Proietti, Michel Lefèvre, Nicholas Larouche, Juan Tian, Juan Herranz, Jean-Pol Dodelet, Nature Communications, 2 (2011).
3. A. Serov, K. Artyushkova, E. Niangar, C. Wang, N. Dale, F. Jaouen, M.-T. Sougrati, Q. Jia, S. Mukerjee and P. Atanassov, Nano Energy, 16, 293 (2015).
4. A. Serov, M. H. Robson, B. Halevi, K. Artyushkova and P. Atanassov, Electrochemistry Communications, 22, 53 (2012).
5. D. Banham, S. Ye, K. Pei, J.-i. Ozaki, T. Kishimoto and Y. Imashiro, Journal of Power Sources, 285, 334 (2015).
Change in Surface Composition of La0.9Sr0.1Ga1-XMgxO3-
d Investigated with Low Energy Ion Scattering Analysis
Authors: Schraknepper Henning , Ishihara Tatsumi 
Published: February 2020

In oxide based energy conversion devices, e.g. fuel and electrolyser (SOFCS and SOECS), predominantly materials crystallizing in the perovskites structure are employed as both, electrodes and electrolyte. Being exposed to realistic operation conditions, however, both components suffer from various degradation phenomena. Here surface segregation and interface diffusion are of pivotal practical importance, as both phenomena are known to deteriorate device performance. Up to now, surface segregation was mainly studied on perovskite oxide cathode and it was found that A site is always segregated surface, in particular, alkaline earth cation is easily segregated on the surface.
In this study, change in surface composition by alkaline earth element in one of the most promising electrolyte material - La0.9Sr0.1Ga1-xMgxO3-
δ (LSGM)- were investigated. Samples of different Mg content x were subjected to anneals at high-(> 1000 K), intermediate ( 1000< T/K < 650) and low temperatures (>650 K). The composition of the very outermost surface layer was subsequently analyzed by means of low energy ion scattering (LEIS). In analyzing the results, the focus was set on differences in A and B side surface coverage and changes with temperature, time and composition.
Moreover, links between Ni diffusion at interfaces observed in devices employing LSGM and the here described surface segregation phenomena in the same material were established.
It was found that Mg2+ in B site was first segregated but after annealed for longer period, Sr2+ in A site was segregated and so the surface segregated cation was changed depending on the annealing period. Decreasing Mg content, Mg segregation is not observed and this is related with the Ni diffusion in LSGM film prepared by dip coating method.