bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Modeling of New Batteries
Authors: Wang Yun 
Published: February 2020

Flow batteries, capable of storing large quantity of energy, have great potential to increase the flexibility of power systems and improve dynamic response to energy demand. Flow batteries are a rechargeable electrochemical energy system, in which electrolytes contain one or more dissolved electroactive species, and the chemical energy in electrolytes is reversibly converted to electricity. The fuel electrolyte is stored externally in a tank, and delivered to the reactor. Batteries can be recharged by replacing electrolytes, similar to conventional vehicles, or by external electric power that is similar to secondary batteries. Flow battery technology offers advantages in energy storage and conversion, including: 1.) large capacity (determined by the external tank volume); 2.) negligible degradation when left completely discharged for long periods; 3.) charge/recharge through electrolyte replacement or external power source; and 4.) no permanent damage when electrolytes are accidentally mixed. Among the major types of flow batteries, the vanadium redox flow battery is a type of rechargeable flow battery that employs vanadium ions at different oxidation states to store chemical potential energy.
Lithium-based batteries have received a great deal of research attention in recent years owing to their relatively high efficiency and energy density. A major hurdle to their development, however, is the insufficient low energy capability as opposed to fossil fuels. The gasoline’s specific energy is about 13,000 Wh/kg, an order-of-magnitude higher than that of Li-ion batteries. Li-air batteries are an emerging area with a great promise of high specific energy storage. Their theoretical specific energy reaches around 11,680 Wh/kg, comparable to gasoline and higher than methanol. Their unique feature is that the cathode active material--oxygen is obtained from the ambient environment, and the anode uses lithium metal, rather than Li intercalated graphite (LiC6) as that in Li-ion batteries. Air cathodes are a major area of study in non-aqueous Li-air battery. In cathodes, Li compounds such as Li2O2 or Li2CO3 are produced during discharging. These substances in general have low solubility in major non-aqueous electrolytes, therefore precipitate at the reaction surface. They are also poor electric conductor, causing electrode passivation. As discharging proceeds, the precipitates accumulate inside the pore network, deteriorating voltage drop.
In this talk, I will discuss the ongoing work of modeling development on RFBs and Li-air batteries at UCI. The models are formulated by rigorously accounting for the conservation of mass, momentum, species, charges, and energy, in conjunction with the electrochemical reaction kinetics of vanadium RFBs and Li-air batteries. I will emphasize the similarity and difference in modeling the two types of new battery systems. The models are validated against experimental data.
(Invited) Luminescent Rare-Earth Doped Thin Film Nanostructures As Building Blocks for Nanophotonic and Lighting Applications
Authors: Camps Ivan , Mariscal Antonio , Serna Rosalia 
Published: February 2020

Active light emitting nanostructured materials are essential elements for the development of compact and efficient devices in applications such as photonics, lighting, safety, sensing and biotechnology. These nanostructured materials require a suitable design and specific choice of wavelength depending on the targeted application. Rare-earth(RE) ions are known for providing a robust and high purity light emission Within this context we aim to design and fabricate nanostructured efficient emitters that will be used as building blocks for the development of the next generation of complex photonic devices that will have integrated functionalities such as emission, switching, processing and detection of light, operating in a wide wavelength range covering the visible-infrared spectrum.
In this talk we will present the recent results obtained by our group using the methodology of embedding nanolayers of rare-earth ions into thin film oxides and oxinitrides with the aim to build efficient nanoemitters. By suitably choosing the nature, composition and crystallinity of the matrix, and the oxidation state of the RE-ion and its concentration and distribution in the nanolayers we will show several examples of functionalized emission. The examples will include the demonstration of narrow emission from pure europium oxide thin films in which fine tuning of the emission is shown by exploiting crystal field effects triggered by stress, the development of efficient wide band emitters in the visible based on Eu2+ doped oxide and oxinitride films, and the demonstration of RGB emission based on a combined doping of RE-ions.
(Invited) Ionophore-Doped Ion-Selective Electrode Membranes
Authors: Buhlmann Philippe , Zhen Xue V , Hu Jinbo 
Published: February 2020

Ion-selective electrodes with ionophore-doped sensing membranes are are highly sensitive and selective analytical tools that offer a variety of advantages, such as simplicity of measurement, high analysis throughput, rapid detection, and low cost of analysis. While such sensors are used in clinical laboratories for billions of measurements every year, applications in biomedical sciences, the food industry, and environmental monitoring are hindered by biofouling and the frequent need for recalibration. With prolonged exposure to biological samples, solid contact polymeric-membrane ISEs exhibit a breakdown of selectivity and response due to biofouling and changes in the phase boundary potential at the interface of the ion-selective membrane and the underlying electron conductor. Therefore, frequent recalibrations are needed for many clinical and biological applications. This talk will discuss experimental techniques such as impedance spectroscopy and hydrodynamic methods to characterize sensor aging, and it will address the use of hydrophobic redox buffers incorporated into the sensing membranes to stabilize the phase boundary potential at the interface to the underlying electron conductor. These redox buffers permit a high electrode-to-electrode reproducibility of the emf response, which is needed for the development of ion-selective potentiometric devices that can be used in a calibration-free manner [1].
[1] Calibration-Free Ionophore-Based Ion-Selective Electrodes With a Co(II)/Co(III) Redox Couple-Based Solid Contact, Zou, X. U.; Zhen, X. V.; Cheong, J. H.; Bühlmann, P. Anal. Chem.,
2014, 86, 8687–8692.
Modeling Standing Waves in a Thin Layer Sonoelectrochemical System
Authors: Landgren Jeffrey K , Strohmer Gerhard , Leddy Johna 
Published: February 2020

Recent experiments in thin layer sonoelectrochemistry demonstrate that sonication increases the rates of electrocatalysis. Heterogeneous electron transfer rates increase substantially upon ultrasound irradiation. A model is developed using Partial Differential Equations and the Finite Element Method to understand catalytic effects observed when sound waves are applied in a thin layer electrochemical cell.
The cell consists of a hollow Teflon cylinder with a transducer as the base, seen in Figure 1. A three electrode system is used with the electrodes spaced equally apart and parallel to the cylinder base. The cylinder is filled with a redox probe and electrolyte solution such that a meniscus forms at the top. The transducer propagates sound waves through the solution (i.e., sonication). A comparison of cyclic voltammograms before, during, and after sonication reveals enhancement effects from the sound waves. For redox probes with slow kinetics, sonication simultaneously increases currents and appears to shift the reaction to more reversible. Data indicate that a combination of the height and shape of the meniscus play a vital role in this enhancement effect.
Partial differential equations is used in conjunction with numerical analysis to develop and solve the model, respectively. The model takes into account the shape and height of the meniscus as well as the pressure, density, elasticity, mass, and surface tension of the fluid near the meniscus. Then the Finite Element Method reveals the standing waves of the system. Standing waves occur in a stationary medium when waves are traveling in opposite directions and cause interference with one another. In general, if this scenario occurs with waves of approximately the same amplitude there is no net change in energy, another indication that the height of the meniscus is relevant.
To help quantify this phenomenon, four equations are used, seen in Figure 2. Following this basis functions in the finite element space are used to convert our continuous problem to a discrete one via the weak formulation. A reduction of the wave equation to an eigenvalue problem gives way to our standing waves in the form of an eigenfunction expansion. The wave interference taking place in the cell can be seen in Figure 1.
This model is important for prediction of behavior of the sound waves before and after they contact the top boundary and the role of the meniscus convexity. This will lead to advances in understanding the experimental system for applications in electrocatalysis.

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(Invited) Application of Density Functional Theory in the Design of Materials for Fuel Cell Applications
Authors: Matanovic Ivana , Atanassov Plamen 
Published: February 2020

Rational design of novel materials for energy applications demands a deeper understanding at the atomic level of the origin of relevant properties of materials and associated processes. The use of Density Functional Theory (DFT) has resulted in major breakthroughs in those efforts and has had an enormous impact both on fundamental and applied materials research. This paper will describe some of the efficient computational tools, which can be used in concert with experimental approaches to explore various aspects in the design of both platinum group metal and non-platinum group matal based materials for fuel cell applications.
The first part will be a discussion of the capabilities of DFT to model the structure of, and catalytic processes on different catalytic materials. Examples include an explanation of the observed catalytic activity of CuCo2O4 ORR/OER bi-functional catalysts by DFT methods, and the structure-property relationships in novel 3D graphene hybrid materials synthetized at UNM [1]. This will be followed by a description of theoretical modeling of the catalyst-ionomer interface, which can identify some key ionomer features of crucial importance for their efficient implementation with the specific electro-catalyst in the anion and proton exchange membrane fuel cells. Examples in this part include the interaction of organic cations with an extended platinum surface and nafion with M-N-C type catalysts. DFT based approaches as a support for spectroscopic measurements of surface phenomena will be discussed in the last part of this talk, including the advantages and disadvantages of DFT in reproducing accurate vibrational spectra of surface bound species [2]. Finally, the use of core level shifts obtained from DFT calculations can facilitate the interpretation of X-ray Photoelectron Spectroscopy (XPS) experiments, and thereby support the effort to determine structure to reactivity relationships that are essential for reaching an understanding of M-N-C catalysts on the molecular level.
[1] A. Serov, N. I. Andersen, A. J. Roy, I. Matanovic, K. Artyushkova, P. Atanassov, CuCo2O4 ORR/OER Bi-Functional Catalyst: Influence of Synthetic Approach on Performance. J.Electrochem. Soc.162 (4) F449-F454 (2015).
[2]I. Matanović, P. Atanassov, B. Kiefer, F. H. Garzon and N. Henson, Applicability of Density Functional Theory in Reproducing Accurate Vibrational Spectra of Surface Bound Species. J. Comput. Chem., 35, 1921-1929 (2014).

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Design of Nanoporous Carbons As Anode Materials for Sodium (Na) Ion Batteries
Authors: Cai Qiong , Karatrantos Argyrios 
Published: February 2020

Sodium (Na) ion battery (NIB) has recently attracted increasing interest worldwide as a promising next-generation energy storage technology, because of the natural abundance, wide availability and low cost of Na resources. Operating at ambient temperature, NIBs provide a safer and sustainable energy storage solution [1,2]. These batteries could potentially approach the performance of Li-ion batteries if optimal electrode and electrolyte materials are identified.
In this project, we focus on the design of the negative electrode materials for Na ion batteries [2]. Nanoporous carbons are one of the materials that have been used as negative electrode materials, providing the necessary low cost, low voltage and good capacity. However, the intercalation mechanism of Na ions into the complicated 3D porous structure is still unknown; these carbons need to be designed and optimized for best performance in NIBs.
By means of atomistic molecular dynamics simulations [3], the diffusion of sodium (Na) ions is investigated for different carbon electrode geometries, such as slit nanopore and rough nanopore, and nanopore sizes. Slit and rough nanopores predict a different Na ion dynamics. Also, for sub-nanometer pore sizes the electrostatic surface charge decreases the Na ions diffusivity inside the nanopore. Our goal is to understand the fundamentals of adsorption and diffusion of Na ions in nanoporous carbons and develop an improved carbon model for the design of these materials.
Acknowledgement
The authors are grateful for funding support from EPSRC.
References
[1] H. Kang, Y. Liu, K. Cao, Y. Zhao, L. Jiao, Y. Wang, H. Yuan, J. Mater. Chem. A 3, 17899 (2015).
[2] V. L. Chevrier and G. Ceder, Journal of The Electrochemical Society, 158, A1011-A1014 (2011).
[3] G. Kamath, R. W. Cutler, S. A. Deshmukh, M. S. Fard, R. Parrish, J. Huether, D. P. Butt, H. Xiong, S. K. R. S. Sankaranarayanan, J. Phys. Chem. C, 118, 13406, (2014).
(Science for Solving Society’s Problems Challenge Grant Winner) eLatrines: Development of a Fully Cardboard based Microbial Fuel Cell for Pit Latrines
Authors: Kretzschmar Jörg , Riedl Sebastian , Brown Robert K. , Schröder Uwe , Harnisch Falk 
Published: February 2020

The aim of the project was to provide full experimental proof-of-concept that stand-alone power generation based on microbial fuel cells (MFCs) operated on human feces from pit latrines as substrate can be achieved. Thereby, the establishment of these eLatrines was based on MFC-technology and the components were to be gained from low-cost materials and through low-tech approaches. For the latter the system was to be developed so as to utilize as many components as possible that can be produced by non-trained persons in decentralized areas for example in developing countries, e.g. the cardboard based electrodes. This presentation summarizes achievements and the lessons learned for i) electrodes gained from corrugated cardboard to be used as anodes and cathodes; ii) anodes being operated using real human feces as substrate; iii) cathodes – with nitrogen functionalities derived from (artificial) urine and based on corrugated cardboard - for oxygen reduction reaction activity; iv) pre-tests on using vent-air from ovens/ fireplaces for allowing low-tech carbonization of corrugated cardboard, v) the operation of the described components in a combined approach under potentiostatic control as well as in fuel cell mode.
In summary, we will show that the overall concept of a stand-alone power generation from human feces in urine can become technically feasible as well as economically and societal relevant. However, the achieved current densities of less than 100 µA/ cm2 (geometric surface area) as well as challenges due to the operation with real, highly inhomogeneous substrates like clogging of electrodes’ pores, formation of insulating fat layers at cathodes, etc. highlight the need for a thorough process engineering.
(Invited) Carbon Nanotube Network As Stable and Efficient Electron Blocking Layer and Transparent Conductive Electrodes for Solar Cells
Authors: Maruyama Shigeo , Cui Kehang , Jeon Il , Chiba Takaaki , Xiang Rong , Chiashi Shohei , Kauppinen Esko , Matsuo Yutaka 
Published: February 2020

Films of single-walled carbon nanotubes (SWNTs) network are promising flexible transparent-conductive electrode for various types of solar cells. Furthermore, adequately p-doped SWNTs network can also act as a stable conductive electron blocking layer (EBL). We have demonstrated these characteristics in honeycomb-structured SWNTs-Si solar cells [1], dry-deposited SWNTs-Si solar cells [2], graphene-Si solar cells, organic solar cells (OSC) [3,4], and perovskite-type solar cells [5]. Millimeter-scale single crystal graphene [6] also exhibits similar properties as SWNTs networks. Air-stable power conversion efficiency (PCE) of about 11 % are demonstrated for SWNT-Si or graphene-Si solar cells without the intentional doping. PCE about 5 % can be obtained for inverted and normal organic solar cells. The EBL and electrode functions of SWNT network were also demonstrated in normal and inverted type perovskite solar cells with over 9% PCE.

References:
[1] K. Cui, T. Chiba, S. Omiya, T. Thurakitseree, P. Zhao, S. Fujii, H. Kataura, E. Einarsson, S. Chiashi, S. Maruyama, J. Phys. Chem. Lett., 4 (2013), 2571.
[2] K. Cui, A. S. Anisimov, T. Chiba, S. Fujii, H. Kataura, A. G. Nasibulin, S. Chiashi, E. I. Kauppinen, S. Maruyama, J. Mater. Chem. A, 2 (2014) 11311.
[3] I. Jeon, K. Cui, T. Chiba, A. S. Anisimov, A. G. Nasibulin, E. I. Kauppinen, S. Maruyama, Y. Matsuo, J. Am. Chem. Soc., 137 (2015) 7982.
[4] I. Jeon, C. Delacou, A. Kaskela, E. I. Kauppinen, S. Maruyama, Y. Matsuo, submitted (2015).
[5] I. Jeon, T. Chiba, C. Delacou, Y. Guo, A. Kaskela, O. Reynaud, E. I. Kauppinen, S. Maruyama, Y. Matsuo, Nano Lett., 15 (2015) 6665.
[6] X. Chen, P. Zhao, R. Xiang, S. Kim, J. Cha, S. Chiashi, S. Maruyama, Carbon, 94 (2015) 810.
(Invited) Regioselective Thiolation of Perchlorinated Graphene
Authors: Tan Yuanzhi 
Published: February 2020

Chemical and physical properties of graphenes are naturally determined by its edge structures. Chemical functionalization is one of promising strategy to modulate the peripheral structure of graphenes. As a molecular-level model system, large polycyclic aromatic hydrocarbons (PAHs), i.e. so-called nanographenes, can be chemically modified through edge functionalization. Although the synthetic protocols for edge substitution of nanographenes are well developed, the regioselective chemical functionalization of nanographenes remains an enormous challenge, most likely due to the lack of suitable synthetic protocols. Here we show a regioselective peripheral thiolation of nanographenes by selective thiolation of perchlorinated nanographene. Based on two model perchlorinated nanographenes C42Cl18 and C60Cl24, we found the chlorines at the vertex of nanographenes are regioselectively substituted by the thiophene-2-thiol, which shows the first case of selective functionalization of nanographenes. The rest chlorines at the bay positions provide the platform for further functionalization. It enables us to design and produce a series of edge functionalized nanographenes.
Figure 1. Regioselective thiolation of perchorinated graphene

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(Invited) Water-Dimer Encapsulations into C84
Authors: Slanina Zdenek , Nagase Shigeru , Akasaka Takeshi , Lu Xing 
Published: February 2020

The water-dimer formation and its encapsulation into D2(22)-C84 and D2d(23)-C84 fullerenes is computed, following similar evaluations [1] with C60. The water-dimer equilibrium populations are calculated using the potential-energy change from the ab initio G3 theory and anharmonic partition functions from the MP2/AUG-cc-pVQZ approach. The encapsulation energetics is treated at the M06-2X/6-31++G** level and it is found that the water-dimer storage in C84 is attractive, yielding an energy gain of more than 10kcal/mol. This substantial encapsulation energy together with the computed temperature increase of the water-dimer population in the saturated steam suggest that the (H2O)2@C84 endohedrals could be produced in a high-temperature/high-pressure approach similarly to encapsulation of rare gases in fullerenes.
[1] F. Uhlik, Z. Slanina, S.-L. Lee, B.-C. Wang, L. Adamowicz, S. Nagase, J. Comput. Theor. Nanosci. 12, 959 (2015); 12, 2622 (2015).
Effect of Antifreeze Additives on Low Temperature Performance of Lithium-Ion Aqueous Battery
Authors: Belgibayeva Ayaulym , Mentbayeva Almagul , Umirov Nurzhan , Molkenova Anara , Adi Akylbek , Kurmanbayeva Indira , Bakenov Zhumabay 
Published: February 2020

Poor low temperature performance of Li-ion batteries is considered as one of the major technical issues restricting their wide application in stationary energy storage systems and energy sources for transportation systems, including electric vehicles. The low temperature deactivates all main reaction steps, such as ionic diffusion/conduction in the electrolyte, Li+ transport through a solid electrolyte interface layer, interfacial charge transfer, and solid state lithium ion diffusion, leading to a remarkably lower kinetics [1]. These losses are even more manifested in case of aqueous rechargeable lithium-ion batteries (ARLBs) due to the higher freezing point of water, although, at room temperature the fast lithium diffusion in aqueous electrolyte media allows for the operations under high electric current conditions.
In this work, we report on investigation of low temperature performance of an aqueous rechargeable battery based on Zn/LiFePO4 system developed in our group [2]. At room temperature, this battery exhibits a superior rate capability with 72 mAh g-1 and 45 mAh g-1 at 30 and 60 C cycling rates, respectively. However, such excellent kinetics could be remarkably reduced at temperatures close and below the solvent (water) freezing temperature, as it can be seen from Fig. 1. Therefore, the effect of addition of antifreezes, such as ethylene glycol or propylene glycol, on the low temperature performance of Zn/LiFePO4 aqueous battery was investigated using galvanostatic charge discharge, ac impedance spectroscopy and other methods.
The further details of this work will be reported at the Meeting.

References

D.P. Abraham, J.R. Heaton, S.-H. Kang, D.W. Dees, A.N. Jansen, J. Electrochem. Soc. 155, A41, (2008).

N. Yesbolati, N. Umirov, A. Koishybay, M. Omarova, I. Kurmanbayeva, Y. Zhang, Y. Zhao, Z. Bakenov, Electrochimica Acta,
152 (2015) 505.

Acknowledgements

This research was supported by a Research Grant from Nazarbayev University.

Figure 1