bluuebunny/crossref_metadata_2025_split huggingface dataset:
Group IV Graphane Analogues As Electronic Materials
Authors: Cultrara Nicholas , Goldberger Joshua E. 
Published: February 2020

Here, we will describe our recent development of the electronic properties, a new family of two-dimensional (2D) materials based on honeycomb, sp3-hybridized Group IV elements. These ligand-terminated Si, Ge, and Sn “graphane analogues” are an intriguing class of 2D materials that offer the potential to tailor the structure, stability, and properties via covalent chemistry. The electronic structure of these materials can be systematically controlled by attaching different surface terminating ligands, and even bestowing properties that don’t exist in the normal three-dimensional structure. For example, with the appropriate surface functionalizing ligand, these 2D materials feature direct band gaps, enhancing silicon and germanium’s performance in photovoltaics, photodetectors, light-emitting diodes, and lasers. These materials can be synthesized in gram-scale quantities, exfoliated as single-layers, and prepared as thin layers directly on Si and Ge wafers. Additionally, we will describe our recent studies on controlling the electronic behavior by doping the lattice with Group III and Group V elements. This class of two-dimensional materials are not only promising building blocks for a variety of conventional semiconductor applications, but also provides a pioneering platform to systematically and rationally control material properties using covalent chemistry.
Evaluating the Electrocatalytic Stability of N-Doped Graphene Nanosheets Used As a Counter Electrode for [Co(bpy)3]3+/2+ Based Porphyrin-Sensitized Solar Cells
Authors: Zhai Peng 
Published: February 2020

A significant improvement in efficiency is achieved for porphyrin (YD2-o-C8) based dye sensitized solar cells, coupled with [Co(bpy)3]3+/2+ mediator electrolyte.However, the poison of
the counter electrode (CE) by the [Co(bpy)3]3+/2+ mediator remains a significant barrier to producing a reliable high-performance device. In this paper, nitrogen-doped graphene
nanosheets (NG) are produced using a low cost solution-based process and used as the CE for [Co(bpy)3]3+/2+ based porphyrin-sensitized solar cell. These produce significantly
better electrocatalytic activity than the commonly used Pt CE. The superior performance is a result of the increased number of catalytic sites and the wettable surface that is caused
by the substitution of pyridinic and pyrrolic N into the carbon conjugated lattice. To the authors’ best knowledge, the significantly improved cycling stability (>1000 times) of NG CE
for [Co(bpy)3]3+/2+ redox complexes is demonstrated for the first time.
Modulation of the Electrostatic and Quantum Capacitance of Few Layered Graphene through Plasma Processing
Authors: Narayanan Rajaram , Yamada Hidenori , Karakaya Mehmet , Podila Ramakrishna , Rao Apparao M , Bandaru Prabhakar R 
Published: February 2020

A comprehensive understanding of the characteristics of graphene1, with regard to its unique electrical2, optical, and structural attributes would be incomplete unless the inevitable presence of defects have been considered. While such imperfections may limit3 the realization of theoretically predicted attributes, they may also be vital for uncovering new fundamental phenomena and their related applications. Here, we show that the charged defect generation, through argon ion based plasma processing, in few layer graphene (FLG) could be integral to the substantial enhancement of the electrical capacitance, and of potential use4 in electrochemical (EC) energy storage5. By combining EC characterization techniques with detailed Raman spectroscopic analysis, we elucidate the contributions of plasma-induced defects to electrostatic and quantum capacitance.
References:
1. Kastnelson, M. I. Graphene: Carbon in Two Dimensions. (Cambridge University press, 2012).
2. Das Sharma, S., Adam, S., Hwang, E. H. & Rossi, E. Electronic transport in two-dimensional graphene. Rev. Mod. Phys.
83,407 (2011).
3. Banhart, F., Kotakoski, J. & Krasheninnikov, A. V. Structural Defects in Graphene. ACS Nano
5,26–41 (2011).
4. Stoller, M. D., Park, S., Zhu, Y., An, J. & Ruoff, R. S. Graphene-based ultracapacitors. Nano Lett.
8,3498–502 (2008).
5. Simon, P. & Gogotsi, Y. Materials for electrochemical capacitors. Nat. Mater.
7, 845–854 (2008).

Figure 1
Fabrication and Properties of Graphene/Polymer Transparent Conductive Composite Film
Authors: Pang Beili , Yu Liyan , Dong Hongzhou , Dong Lifeng 
Published: February 2020

Graphene shows many exceptional properties, such as electrical, thermal, optical, and mechanical properties. When it was used as nanofiller in the preparation of polymer nanocomposites, the properties of the polymer matrix could not be fully exhibited due to easy agglomeration of graphene and bad compatibility between polymer matrix and graphene.[1,2] Polyurethane (PU) is a material characterized by excellent flexibility, high resilience, and durability. PU has been applied in a wide range of industrial applications including coatings, adhesives, foams, and elastomers.
In our study, the surfactant was first introduced to improve the dispersion of graphene in distilled water. The PU copolymer was synthesized with 2, 4-toluene diisocyanate, polyethylene glycol (PEG400) and 2-hydroxyethyl methacrylate. The triethylamine and ethylene diamine reacted with the copolymer as the neutralizing agent and chain extander, respectively. The graphene/PU polymer composite film was cast on glass substrate and cured under UV irradiation. Dispersion of graphene in the polymer matrix strongly depended on the type of surfactant agent, which was confirmed by scanning electron microscopy measurements and thermogravimetric analysis. Decomposition temperatures and residues of the samples increased with the increasing of graphene content. The conductivity of the films was evidently improved due to the introduction of graphene, which was investigated by using a four probe tester. The composite films were bright and transparent. The graphene/PU polymer composite film showed satisfactory conductivity, transparency and thermal resistance properties because the graphene was well dispersed in the polymer matrix. These polymer composite thin films are good candidates that can be applied in various electronic devices such as counter electrode in solar cells, anode materials in rechargeable batteries and light emitting diodes, and so on.
Reference:
[1] H. B. Zhang, W. G. Zheng, Q. Yan, Z. G. Jiang, Z. Z. Yu, Carbon, 50, 5117 (2012).
[2] J. H. Du, H. M. Cheng, Macromol. Chem. Phys. 213, 1060 (2012).
Formulation and Micro-Extrusion of High Graphene or Activated Carbon Loaded Slurries
Authors: Li Ling , Imran Shaik Mohamed , Shaw Leon 
Published: February 2020

Our study is focusing on how the dispersion of solid ingredients in solvent affects the micro-extrusion performance. The slurries comprising high loading of graphene (GN) and carbon black (CB) in solvent N-methyl-2-pyrrolidone (NMP) or DI water with SDS are prepared. In addition the capability of the extrudate to maintain its shape right after extrusion of the slurries will influence the micro-extrusion performance. Six key parameters will be studied, including (a) the pH value, (b) the salt concentration, (c) the solid loading, (d) the extrusion rate (cm3/sec), and (e) drying speeds (static air drying or flowing air drying). To avoid phase separation, we will design the orifice size according to the GN size. For the activated carbon slurries, we also investigated the aqueous system and the micro-extrusion performance.
Eta6 chemical Modification of Epitaxial Graphene: An Avenue for Non Destructive Surface Functionalization and Atomic Layer Deposition
Authors: Che Songwei , Sreeprasad Theruvakkattil Sreenivasan , Nguyen Phong , Berry Vikas 
Published: February 2020

Graphene is one atom thick planar sheet and has been applied in many fields due to its distinct properties, such as high carrier density, ballistic transport and high thermal conductivity. Its superior properties are expected to further expand its electronic application by functionalizing graphene with other moieties. However, in most cases functionalization leads to the conversion of planar hybridized sp2 state to tetrahedral sp3 state. This conversion results in the increased carrier scattering and reduced carrier density. In this talk, we demonstrate a novel η6 functionalization route, where epitaxial graphene can react with Chromium hexacarbonyl solution at low temperature. Raman spectroscopy and X-ray photoelectron spectroscopy are employed for surface characterization. Two Chromium peaks exist in XPS confirming (a) the grafting of chromium tri-carbonyl on the graphenic aromatic rings, and (b) interaction between the pi-cloud of graphene and the d-orbital of Chromium. The Raman 2D-peak blue shifts indicating back donation between Chromium and carbon rings. There is no D-band in Raman spectroscopy showing the sp2 carbon character in the lattice is preserved. Besides, the electrical properties of functionalized graphenes and their application in sensing will also be discussed. The results clearly show that its superior properties including high carrier density, low carrier scattering and high sensitivity are maintained.
Fundamental Studies of Iron Redox Flow Battery Electrochemistry in a Deep Eutectic Solvent
Authors: Miller Mallory A. , Wainright Jesse S. , Thompson Levi T , Savinell Robert F. 
Published: February 2020

Current redox flow battery (RFB) technologies are limited by low energy and power densities; thus, a recent focus has been on non-aqueous electrolytes. Although organic solvents allow for increased voltage windows, they possess a sensitivity to moisture, low active species solubilities, high flammability and toxicity, and limited availability. Another class of non-aqueous solvents, ionic liquids (IL) or more specifically, deep eutectic solvents (DES) offer promise for future non-aqueous RFBs. These “designer solvents” can be created using a number of combinations of bulky asymmetric cations and weakly coordinating anions, allowing for the ability to tailor different solvent properties, presenting an opportunity to generate optimized solvents. DES are advantageous in that they have large electrochemical windows similar to organic solvents, and they have low volatilities, high thermal stabilities, high polarities, and high conductivities without the need for a supporting electrolyte [1-4]. They offer a “greener” alternative to volatile organic solvents and are non-toxic and nonflammable [5, 6]. Two different deep eutectic systems, reline (1:2 molar ratio choline chloride and urea) and ethaline (1:2 molar ratio choline chloride and ethylene glycol), have been investigated as well as an iron eutectic (1:3 molar ratio iron chloride and ethylene glycol). Wide potential windows of 2.6V and 2.0V are achieved using reline and ethaline respectively (compared to 1.23V for aqueous). Electrolyte properties such as conductivities and viscosities as a function of temperature are reported. Iron plating efficiencies are reported; higher coulombic efficiencies compared to the aqueous system are attributed to elimination of the side reaction of hydrogen evolution (due to the expanded voltage window). Characterization of the electrokinetics, diffusion coefficients, and solubility of the iron chemistry at 50°C have been determined using voltammetric measurements and electrochemical impedance spectroscopy at platinum, glassy carbon, and carbon fiber microelectrodes. Iron was chosen as proof of concept chemistry; higher potential couples are currently under investigation.
[1] S.-H. Wu, Thermochimica Acta, vol. 544, pp. 1-5, 2012.
[2] G. A. Baker, S. N. Baker, S. Pandey, and F. V. Bright, Analyst, p. 800, 2005.
[3] T. Welton, Chem Rev., p. 2071, 1999.
[4] S. A. Forsyth, J. M. Pringle, and D. R. MacFarlane, Aust J. Chem, vol. 57, 2004.
[5] M. J. Earle and R. K. Seddon, Pure Appl. Chem., vol. 72, p. 1391, 2000.
[6] K. N. Marsh, A. Deev, A. C.-T. Wu, T. E., and A. Klamt, Korean J Chem. Eng. , vol. 19, 2002.

Figure 1
Lithium Ion Dynamics in Amorphous Li-Si Electrochemically Prepared from Semiconductor Grade, Monocrystalline Silicon - an NMR Study about Local Structures and Li+ Self-Diffusivity
Authors: Dunst Andreas , Sternad Michael , Epp Viktor , Wilkening Martin 
Published: February 2020

Silicon is one of the most promising anode materials for lithium-based rechargeable batteries. Provided the volume changes during Li uptake can be brought under control, Li ion diffusivity is expected to crucially determine the performance of such energy storage systems. Therefore, studying diffusion properties in amorphous Li-Si underpins applied research that is being directed towards the development of powerful storage devices. So far, only little information is available on Li self-diffusion in amorphous Si. Here, we used 7Li NMR spectroscopy [1] to precisely quantify microscopic activation energies and Li jump rates in amorphous Li-Si which is primarily formed if monocrystalline Si is lithiated electrochemically. Our results reveal relatively fast Li diffusivity with an average activation energy for long-range ion transport as high as ca. 0.65 eV; jump rates turn out to be in the order of 2.5 × 105 1/s at 246 K, see also ref. [2]. Comparisons with data from laboratory frame NMR relaxometry, which is sensitive to more localized ion hopping, points to complex dynamics that is most likely governed by non-exponential motional correlation functions originating from a large distribution of activation energies. Noteworthy, a second sample, which is a mixture of amorphous Li-Si and metastable, crystalline Li15Si4 that forms at lower discharge potentials, points to slightly enhanced Li diffusivity (0.51 eV). Interestingly, ﬁrst high-resolution 6Li MAS NMR experiments on X-ray amorphous Li-Si, which have been carried out using isotope enriched samples, indicate the presence of structural motifs that resemble those of Li12Si7. The data obtained might help optimizing Li-based silicon batteries whose performance critically depend on fast Li-ion transport.

Acknowledgement Financial support by the Federal Ministry of Science, Research and
Economy and the National Foundation for Research, Technology and Development is gratefully acknowledged.

References

[1] V. Epp, M. Wilkening, Phys. Rev. B 82 (2010) 020301.
[2] A. Kuhn, P. Sreeraj, R. Pöttgen, H.-D. Wiemhöfer, M. Wilkening, P. Heitjans, J. Am. Chem. Soc. 113 (2011) 11018.
Characterization of Carbon Black Particles for Use in Aqueous Slurry Electrodes
Authors: Hoyt Nathaniel C , Agar Ertan , Nagelli Enoch A. , Savinell Robert F , Wainright Jesse S. 
Published: February 2020

Flowable slurry electrodes have received renewed interest in recent years for use in electrochemical systems. Applications include, but are not limited to, electrochemical energy storage (e.g. flow batteries1,2 and electrochemical flow capacitors3) and desalination (e.g. flow electrode capacitive desalination systems4). All of these applications share similar, but distinctly different, requirements for the solid constituent of the slurry. For example, some systems might favor high electronic conductivity while others could place more of a premium on possessing a high specific surface area.
Carbon particles are often used as the solid constituent in these slurries as they often possess high values of both of these desirable properties. Carbons slurries examined in past research have included activated carbons, carbon blacks, and other more exotic carbons (multi-walled carbon nanotubes, graphene, etc.)5. The selection of slurry constituents inevitably involves trade-offs, however. While activated carbons may possess high specific areas, slurries composed of these particles have low conductivities. Conversely, highly conductive carbons generally do not possess high specific areas. For any of these particles, if the surface chemistry does not permit high loadings, then both the specific area and the conductivity are likely to suffer.
In this presentation we will discuss how the optimal selection of slurry properties varies depending on the given application in which the slurry electrode is intended to be used. The slurry properties of a wide array of different carbon black particles in aqueous electrolytes will also be presented, and good candidates for use in specific electrochemical systems will be discussed.
[1] M. Duduta, B. Ho, V. Wood, P. Limthongkul, V.E. Brunini, W.C. Carter, Y.M. Chiang, Advanced Energy Materials, 1, 511-516 (2011)
[2] T. Petek, N. Hoyt, J. Wainright and R. Savinell, "Slurry Electrodes for Iron Plating in an All-Iron Flow Battery," submitted to J. Power Sources, 2015.
[3] V. Presser, C. Dennison, J. Campos, K. Knehr, E. Kumbur, Y. Gogotsi, Advanced Energy Materials, 2, 895-902 (2012)
[4] S. Jeon, H. Park, J. Yeo, S. Yang, C.H. Cho, M.H. Han, D.K. Kim, Energy Environ. Sci., 6, 1471 (2013)
[5] M. Youssry, L Madec, P. Soudan, M. Cerbelaud, D. Guyomard, B. Lestriez, Phys. Chem. Chem. Phys., 15, 14476 (2013)
Manganese-Based Redox Flow Batteries for Grid Energy Storage
Authors: Swartz Christopher R , Lipka Stephen M , Long Katelyn F. , Kodenkandath Thomas 
Published: February 2020

Redox flow batteries (RFBs) are secondary battery systems suitable for large-scale, stationary energy storage applications, and are capable of storing large quantities of energy (MWh) and power (MW).1 One principle advantage of flow batteries is the ability to decouple energy and power density, and scale both independently. The all-vanadium RFB represents the current state-of-the-art in flow battery technology, but uses expensive ion exchange membranes including Nafion®, and the relatively high cost of vanadium leads to expensive electrolytes.2

The development of manganese-based anolytes as a suitable alternative to vanadium anolytes for redox flow batteries is attractive for various reasons, including a higher reversible potential for Mn2+/Mn3+ than VO2+/VO2
+, higher natural abundance, and lower cost than vanadium. Flow battery anolytes based on the Mn2+/Mn3+ redox couple have been reported in the literature, and the high standard electrode potential of Mn2+/Mn3+ (1.51 V) has been utilized in manganese anolyte (Mn2+/Mn3+)/vanadium catholyte (V2+/V3+) redox flow batteries, featuring a theoretical open circuit voltage of 1.77 V.2,3 The usage of manganese anolytes can lead to a higher cell voltage, yet the disproportionation reaction of Mn3+ is a technical hurdle that needs to be resolved in order for manganese-based anolytes to find widespread utility in redox flow batteries.2,4

This presentation will disclose investigations on the development of manganese-anolyte based redox flow batteries, and will show results from two different systems, including Ti/Mn, and V/Mn. Half–cell and full cell performance metrics, including cycle life testing, will be presented for each system.
References
1) Wang, W. et al. J. Power Sources.
2012, 216, 99.
2) Xue, F.-Q. et al. Electrochimica Acta.
2008, 53, 6636.
3) Hong, T.; Xue, F. “Investigation on manganese (Mn2+/Mn3+)-vanadium (V2+/V3+) redox flow battery.” 2009 Asia-Pacific Power and Energy Engineering Conference (APPEEC).
4) Swartz, C. R.; Lipka, S. M.; Rogers, F. III; Chen, R.; Kodenkandath, T. “Aqueous Manganese-Based Electrolytes for Redox Flow Batteries.” ECS abstract MA2014-02, 616.
Model-Based Techno-Economic Analysis of Battery Function for Energy Storage of Solar Energy
Authors: Lawder Matthew T , Subramanian Venkat 
Published: February 2020

By its nature solar power is intermittent. Because the amount of solar power generation cannot be controlled the economic value energy from a solar array is devalued. Adding energy storage can remove the intermittent nature of solar power (see figure 1), but will increase the overall cost of electricity supplied from the system. The model developed for this study analyzes the operational characteristics and economics of adding a battery system to solar arrays in different regions around the country. The technologic and economic benefits of battery systems are assessed on an individual site basis.
A system level model includes a battery component based on electrochemical and transport principles, a solar array that accounts for site-based irradiance patterns, and a dispatch and control structure that controls the flow of power between generation and demand [1]. The battery component is the focus of the system level model and is studied to understand how the battery will function under dynamic application cycling. The irradiance data for US sites was obtained from the NREL MIDC database which contains minute resolution irradiance data for all the sites studied [2]. The battery model includes a study of how variation in irradiance will affect capacity fade by including fade side reactions into the model.
Metrics studied include battery sizing, battery utilization, battery degradation, system autonomy, solar energy utilization. Additionally, the economic value of systems were studied based on time-of-use pricing scenarios to determine break-even points for adding battery to solar arrays for non-utility customers. The economic analysis is informed by the battery utilization and system autonomy studied in the model. Comparisons of individual sites and solar+battery systems were studied. These model-based studies are important for determining the utility of batteries in conjunction with renewable applications.

Acknowledgements

The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS), as well as, Washington University in St. Louis’ McDonnell Academy Global Energy and Environmental Partnership (MAGEEP).

References

1. S. Santhanagopalan, Q. Z. Guo, P. Ramadass, and R. E. White, Journal of Power Sources,
156, 620(2006)
2. National Renewable Energy Laboratory. (2014, 2014). Measurement and Instrumentation Data Center (NREL). Available: http://www.nrel.gov/midc/

Figure 1