bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrooxidative Polymerization of Aniline in Phosphonium Ionic Liquids and Characterization of the Polyaniline Films
Authors: Tsunashima Katsuhiko , Ito Daiki , Matsumiya Masahiko , Ono Yasushi
Published: February 2020

Room-temperature ionic liquids (RTILs), i.e. organic molten salts with melting points below 100 ◦C, have been intensively developed for electrolytic media in various electrochemical systems due to the fact that RTILs have unique physicochemical properties such as favorable solubility of organic and inorganic compounds, relatively high ionic conductivity, no measurable vapor pressure, high thermal stability, low flammability, etc. Particularly, RTILs have been regarded as potential electrolytic media for electropolymerization processes.1 Many kinds of RTILs have been investigated for the electropolymerizations; however, highly conductive and stable RTILs based on quaternary phosphonium cations2 have been rarely employed for this application. In this work, we report the electrooxidative polymerization of aniline in triethylpentylphosphonium bis(trifluoromethylsulfonly)amide (P2225-TFSA) and tributylmethylphosphonium bis(trifluoromethylsulfonly)amide (P4441-TFSA) in comparison with the other type of RTILs, characterizing the obtained polyaniline films.

The preparation of the phosphonium RTILs was performed by aqueous ion exchange reaction of the precursor quaternary phosphonium halides with lithium TFSA. The electrooxidative polymerization of aniline in phosphonium RTILs containing 0.1 M H-TFSA was carried out by cyclic voltammetry (CV) method using a three-electrode cell equipped with a Pt disk working electrode. The electrochemical activity of the polyaniline films were evaluated by extended CV scanning technique.

Figure 1 shows typical cyclic voltammograms for the electrooxidative pocesses of aniline. As shown in Fig. 1, it was found that relatively large voltammetric response was observed in P2225-TFSA when compared to that in P4441-TFSA. This seems to be attributed to the relatively low viscosity and high conductivity of P2225-TFSA. In addition, the voltammetric responses were enhanced by cycling, which indicates that ionic species could be efficiently doped into the polyaniline film. The surface morphology based on SEM images of the polyaniline films will be also discussed.

References

1  K. Sekiguchi, et al, J. Electroanal. Chem.
,
557, 1 (2003).

2  K. Tsunashima, et al, Electrochem. Commun., 9, 2353 (2007).

Figure 1
(Invited) Sunlight-Driven Ionic Power Generation from Bipolar Ion-Exchange Membranes Functionalized with Photoacids
Authors: White William , Reiter Ronald S. , Ramirez Claudia P. , Sanborn Christopher D. , Ardo Shane
Published: February 2020

Bipolar membranes are a class of polymeric ion-exchange materials that consist of a cation-exchange membrane that is in intimate contact with an anion-exchange membrane. They are unique among the ion-exchange membranes in that they that separate and maintain pH differences across the membrane even during passage of ionic current. Moreover, the physics of ion equilibration processes within these membranes resembles that which occurs during equilibration of semiconductor pn-junctions.

In my presentation I will report on my research group’s recent results from measurements of the electrochemical behavior of bipolar membranes under conditions relevant to solar fuels devices. We identified a condition where the energy required to electrolyze water was seemingly less than 1.23 V, which we showed was due to transport of ions other than protons and hydroxide ions. This subtlety will be explained in great detail to clarify misunderstandings in the interpretation of current–voltage behavior of bipolar membranes.

My research group has also recently successfully demonstrated ionic power generation through solar light harvesting in dye-sensitized ion-exchange membranes. Visible light illumination of photoacid-functionalized Nafion membranes drove endergonic excited-state proton transfer and a photovoltage and photocurrent resulted. Photoacid molecules convert the energy in light into a change in the chemical potential of protons via a weakening of protic functional groups on the photoacid, i.e. a drop in its pK
a. Many photoacids absorb visible light poorly and so a secondary research thrust on this project is to develop new visible-light-absorbing photoacids. Toward this, we have developed the first Ir-based inorganic coordination compound photoacids and quantum dot photoacids. Visible-light excitation of these molecules resulted in clear observation of effective photoacid behavior. Calculation of the excited-state pK
a and ongoing work to comprehend the analysis of photoacid behavior in complex systems will be covered.

The applicability and practicality of bipolar membranes in solar fuels devices and as standalone ionic photoelectrochemical devices will also be discussed. As most of these materials, techniques, and analyses are new to the artificial photosynthesis community, we plan to carefully present the results of our studies and provide ample explanations. Collectively, this body of work represents several new directions in artificial photosynthesis research and development that are being pioneered by my research group.
Is It Greener? Impact of Cathode Catalyst Performance on Life-Cycle Emissions of Producing Methanol By Electrocatalytic CO2 Reduction
Authors: Pellow Matthew , Benson Sally
Published: February 2020

Direct electrocatalytic reduction of carbon dioxide (deCO2rr) is being developed as a route to energy-dense liquid transportation fuels for a low-emissions future. This technology would reduce net emissions from fuel combustion, because these would be fully offset by upstream capture of the CO2 used to produce the fuel. However, it would produce some additional emissions from related processes, such as generating the process electricity and purifying the product stream. Although extensive basic-science catalysis research is underway in this area, the full life-cycle emissions of this technology platform have not been quantified.

In this prospective technology analysis, we apply systematic life cycle assessment (LCA) to estimate the total life cycle emissions associated with producing methanol from low-temperature electrocatalytic reduction of CO2. This analysis framework (1) quantifies the emissions impact of using deCO2rr to provide drop-in liquid hydrocarbon fuels, and (2) provides catalyst performance targets (faradic efficiency, overpotential, and yield) for this technology to provide net emissions reductions. The framework provides a long-term emissions impact perspective to guide priorities in catalysis research for sustainability.

The hypothetical reference case deCO2rr system in this analysis features a cathode electrocatalyst that reduces CO2 to methanol with 15% faradaic efficiency, 0.8 V overpotential, and 25% conversion of CO2 to product. Water is oxidized at the anode. The methanol production system is coupled to CO2 capture from a coal-fired power plant. In a preliminary analysis of this integrated methanol-electricity system, the products (1 g MeOH plus 6.1 Wh of electricity) have a total emissions intensity of 3.8 g CO2. This is approximately half the emissions produced when using conventional processes to produce the same electricity (without carbon capture) and methanol (using a natural gas-based process).

In addition, we quantify the emissions impact of improving the performance of the CO2 reduction catalyst from present values. We identify technology performance thresholds for this renewable methanol process to provide a net emissions reduction compared to conventional processes. For instance, we estimate that using present-day CO2 capture technology, the integrated electricity-methanol production system would provide a net reduction in emissions if the cathode catalyst has 20% faradaic efficiency and 20% molar conversion of CO2 to methanol.
Catalytic Activities of Sulfur Atoms in Amorphous Molybdenum Sulfide (MoSx) for the Electrochemical Hydrogen Evolution Reaction
Authors: Yeo Boon Siang
Published: February 2020

In-situ Raman spectroscopy during cyclic voltammetry was used for the first time to investigate the hydrogen evolution reaction (HER) occurring on electrodeposited amorphous MoSx films, which consist of Mo3-based motiffs. A Raman peak at 2530 cm-1 was observed on these films during HER in aqueous HClO4 electrolyte. This peak was assigned as a MoS-H stretching vibration. This identification was corroborated by H/D isotopic exchange experiments. Hence, we could directly establish that sulfur atoms are the catalytic active sites in amorphous MoSx for proton reduction.

We further distinguish the activities of the S atoms present in these amorphous films. Using X-ray photoelectron spectroscopy as a means to identity the types of S atoms present, we found that the turnover frequency for H2 production increases linearly with the percentage of S atoms with higher electron binding energies. These S atoms could be apical S2- and/or bridging S2
2-. Quantum chemical simulations using density functional theory rule out the apical S2- atoms as reaction sites for HER. In situ Raman spectroscopy of the model [Mo3S13]2- cluster further demonstrate the higher catalytic reactivity of the bridging S2
2- over terminal S2
2- (which have lower electron binding energy) for proton reduction.
Hierarchically Structured Zinc Oxide Gas Sensors with Silver Catalyst
Authors: Chung Yoonsung , Park Hyejin , Lee Eunji , Kim Dong-Joo
Published: February 2020

During the last few years, interest in wearable devices including a portable and wearable gas sensor system has increased. Since integration of fabric and gas sensors for a wearable breath monitoring system would allow continuous monitoring patients’ breathing gases such as acetone gas for diabetes (1), ammonia for renal disease (2), and ethanol for hepatic steatosis (3), realization of a miniaturized wearable gas sensor operating at daily environment is in demand.

Zinc oxide has definite advantages over other semiconducting nano-scale metal oxides because of its electric properties such as wide bandgap and high electron mobility (4). ZnO nanostructures have been investigated such as nanorods, nanotubes, and nanowires. Recently, hollow micro/nanosphere ZnO has been attracting attention. It may be able to apply for dye-sensitized solar cells, photocatalts, high performance electrodes, and gas sensors due to its large surface-to-volume ratio and reduced transport lengths for both mass and charge transport (5).

The researches about the catalytic decoration of ZnO gas sensors by metallic nanoparticles or layers have been also investigated to improve selectivity (6, 7). Especially, ZnO with silver is considered to exhibit relatively high sensitivity to ethanol (7). 

In this study, the hollow microsphere ZnO particles were prepared by a simple but new precipitation method and then Ag sputter coated. Electrophoretic deposition (EPD) of the hollow particles with Ag was then used to construct ZnO-Ag layers on flexible polyimide films. The structural properties of the deposited ZnO layers were analyzed by using SEM, TEM, and XRD.  Then, gas sensing behaviors to detect ethanol, acetone, and ammonia by thickness of Ag are discussed in detail.

This research was partially supported by the Korea Institute of Energy Technology Evaluation and Planning (20158520000210) grant funded by the Korea Government Ministry of Trade, Industry and Energy, a grant from a Strategic Research Project (2013-0132) funded by the Korea Institute of Construction Technology, and Auburn University IGP.

(1) Zhang, Q., Wang, P., Li, J., and Gao, X. (2000) Biosens. Bioelectron.
15, 249-256

(2) Moorhead, K. T., Lee, D., Chase, J. G., Moot, A., Ledingham, K., Scotter, J., Allardyce, R., Senthilmohan, S., and Endre, Z. (2008) Computer methods and programs in biomedicine
89, 226-238

(3) de Lacy Costello, B., Ewen, R., Ratcliffe, N. M., and Richards, M. (2008) J. Breath Res.
2, 037017

(4) Ahn, H., Park, J.-H., Kim, S.-B., Jee, S. H., Yoon, Y. S., and Kim, D.-J. (2010) Electrochemical and Solid-State Letters
13, J125-J128

(5) Xie, Q., Li, J., Tian, Q., and Shi, R. (2012) Journal of Materials Chemistry 22, 13541-13547

(6) Lupan, O., Chow, L., Ono, L. K. Ono, Cuenya, B. R., Chai, G., Khallaf, H., Park, S., and Schulte, A. (2010) The Journal of Physical Chemistry C
114, 12401-12408

(7) Lyashkov, A. Yu, Tonkoshkur, A. S., Aguilar-Martinez, J. A. and Glot, A. B. (2013) Ceramics International
39, 2323-2330
Real-Time Monitoring of Superoxide Anion Radical and Hydrogen Peroxide Generation in Higher Plants in Response to Wounding: In-Vivo Electrochemical Study
Authors: Prasad A. , Takahashi A. , Fujii R. , Matsuoka R. , Kikuchi H. , Aoyagi S. , Aikawa T. , Kondo T. , Yuasa M. , Tada M. , Kobayashi M. , Pospíšil P. , Kasai S.
Published: February 2020

The growth and development in plants are deleteriously affected by various biotic and abiotic stress factors. Wounding in plants occurs with exposure to environmental mechanical stresses or via herbivory. The response of plants towards wounding have been categorized based on the response time; the fast response includes oxidative burst accompanied by generation of reactive oxygen species (ROS) or delayed response which includes transcriptional activation of wound-induced genes, deposition of callose, accumulation of proteinase inhibitors and hydrolytic enzymes etc. The oxidative burst in response to wounding is known to be associated with the formation of various ROS such superoxide anion radical (O2
•−), singlet oxygen and hydrogen peroxide (H2O2). In the current study, we provide experimental evidences and real time monitoring of O2
•−
and H2O2 generation following wounding in leaves of spinach (Spinacia oleracea).

Real-time monitoring of ROS generation was achieved using amperometric method utilizing different electrodes. Non-specific real-time measurements of ROS were done by monitoring the changes in reduction current using carbon electrode while qualitative and quantitative measurement of O2
•−
and H2O2 generationwere done using newly developed iron-porphyrin based modified carbon electrodes and osmium-horseradish peroxidase (Os-HRP) based modified carbon electrodes, respectively. The results obtained showed continuous generation of O2
•− and H2O2 for minutes after injury followed by a decline. The activation of lipoxygenase after wounding; its involvements in the production of H2O2 and the contribution of H2O2 in generation of local response in injured plant tissue besides the initiation of systemic response caused by hormones such as jasmonic acid, ethylene, salicylic acid, and abscisic acid will be disscussed.
Detection of Cortisol in Pbs Buffer and Fish Blood Plasma By Electrochemical Impedance Spectroscopy
Authors: Pali Madhavi L , Suni Ian Ivar
Published: February 2020

Cortisol (MW = 362.5) is a steroid hormone produced in the human body by the adrenal gland in response to elevated levels of stress. Normal levels of cortisol in the human body range from 6-23 microgram per deciliter. Cortisol has also been widely studied in order to better understand fish physiology, with applications to fish ecology and fish farming, since cortisol levels can also be employed as a biomarker for reproductive activity. 

Following immobilization of the polyclonal antibody to cortisol atop an Au electrode, we have detected cortisol in both PBS buffer solution and fish blood plasma, with a detection range up to 0.5 microgram/ml.  Binding of cortisol approximately follows the Langmuir adsorption isotherm, and the detection range is limited at high concentrations by saturation of the antibody film.  This allows the use of sample dilution to reduce the physiological concentration of cortisol down to the range in which it can be detected by impedance biosensing.  The advantage of this approach is that non-specific adsorption is also dramatically reduced by sample dilution.  Non-specific adsorption in this system is unmeasurable, due to both the use of sample dilution and the use of BSA for surface blocking.
Rapid Detection of Live Versus Dead Bacteria
Authors: Horikawa Shin , Liu Yuzhe , Du Songtao , Chen I-Hsuan , Wikle Howard Clyde , Chin Bryan A.
Published: February 2020

This paper presents a rapid method of detecting live versus dead pathogenic bacteria. The method combines phage-coated magnetoelastic (ME) biosensors and a wireless planar coil detector, enabling real-time monitoring of the growth and viability of specific bacteria in a nutrient broth. The ME biosensor used in this investigation is composed of a strip-shaped ME resonator (1 mm x 0.2 mm x 30 um) upon which a landscape phage is coated to capture specific bacteria. E2 phage with high binding affinity for Salmonella Typhimurium was used as a model study. The specificity of E2 phage has been reported to be 200 in 108 background bacteria. When the binding of Salmonella occurs, the mass of the biosensor increases, which simultaneously results in a decrease in the biosensor's resonant frequency. Monitoring of this mass-induced resonant frequency change allows for the instantaneous detection and quantification of Salmonella. ME biosensors with a pre-determined resonant frequency were first exposed to a low-concentration Salmonella suspension to capture a small but detectable amount of the bacteria on the sensor surface. The wireless coil detector was then used to measure the resonant frequency changes of the biosensors as a function of time in a nutrient broth. Live cells can grow, while dead ones can't, which leads to distinct differences in the resonant frequency changes over time. Hence, this methodology offers direct, real-time detection, quantification, and viability determination of specific bacteria.
Nanostructured Sensors for Biomedical Diagnosis and Environmental Monitoring
Authors: Gao Xuefei , Wu Nianqiang
Published: February 2020

Integration of nanostructured materials into sensors is an effective strategy to improve the performance of sensors, in terms of selectivity, sensitivity, response time and reliability. Herein, we present the design and fabrication of various nanostructured sensors and their applications in biomedical diagnosis and environmental detection. The nanostructured sensors can be integrated with plastic microfluidics and paper-based test strips to enable point-of-care tests. Several types of sensors including surface-enhanced Raman scattering sensors, colorimetric sensors, surface plasmon resonance-enhanced fluorescent sensors and electrochemical sensors are demonstrated for biomolecule and environmental pollutant detection.
(Invited) Recent Density Functional Theory Investigations in Electrode Materials for Rechargeable Batteries
Authors: Arroyo-de Dompablo Elena
Published: February 2020

First-principles computation is recognized as an invaluable tool in designing new electrode materials for lithium ion batteries (LIBs). Numerous achievements in predicting relevant properties (including voltage, structure stability, electronic property and ionic mobility) of electrode materials for LIBs using Density Functional Theory has been reported in the last two decades (see, for instance, reference 1). Beyond the LIB technology, computational tools are critically important to enable the development of alternative energy storage technologies. In the last years, concerns on Li availability have prompted the search for suitable alternatives to rechargeable LIBs.  Batteries based on multivalent charge carriers (Mn+) can exhibit advantages in terms of energy density since for a certain amount of M carriers the capacity is doubled (n=2) or tripled (n=3) when compared to single valent carriers like Li+ or Na+. Calcium is an attractive candidate due to its low cost, natural abundance and low reduction potential. The feasibility and reversibility of calcium plating in conventional alkyl carbonate electrolytes at moderate temperatures has been recently reported [2]. Such finding opens the way to the development of a new rechargeable battery technology using calcium anodes.  The identification of potential cathode and anode materials is a must to open the research avenues for the new calcium based battery technology (CIBs). In this contribution, we will show recent progress in first principles computation in predicting, understanding and improving the electrochemical properties of selected electrode materials for Li, Na, Mg and Ca ion batteries. 

Acknowledgments: The author thanks P. Tartaj (LIBs), F. Bardé (CIBs) and M.R. Palacin for the experimental work. Financial support from Ministerio de Ciencia e Innovación (grant MAT-2011-24757) and Toyota Battery Research division at Higashi Fuji (M6) is acknowledged.

[1] Y.S. Meng and M.E. Arroyo-de Dompablo, Energy and Environ. Science 2, 589, 2009

[2] A. Ponrouch, C. Frontera, F. Barde, M. R. Palacin. Nature Materials, DOI:10.1038/NMAT4461
(Invited) Critical Roles of Interface Engineering in All-Solid-State Li-Ion Batteries: Insights from First Principles Calculations
Authors: Mo Yifei
Published: February 2020

All-solid-state Li-ion battery based on solid electrolyte materials is a promising next-generation Li-ion battery technology with intrinsic safety, high energy density, and enhanced cyclability. The key problem in enabling this new battery technology is the high interfacial resistance and interfacial degradation at the solid electrolyte-electrode interfaces. In this presentation, I will show how we use computational modeling to provide unique insights into the fundamental mechanisms at these buried interfaces, which are difficult to access in experiments. I will first demonstrate using first principles computation to predict various materials properties of the solid electrolyte materials with little experimental input. In addition, we systematically investigate and compare the electrochemical stability and chemical stability of the solid electrolyte-electrode interfaces, and study how these interfaces affect the interfacial resistance, low cyclability, and mechanical failure in all-solid-state Li-ion batteries. Our computation results suggest the formation of decomposition interphase layers in all-solid-state Li-ion batteries and the significant effects of the interphase layers on the electrochemical performance of the all-solid-state Li-ion batteries. Different interfaces between solid electrolyte and electrode materials may have different problems at the interfaces, which require different interfacial engineering strategies to resolve. The mechanisms of artificial layers to improve the interfacial properties are revealed by our computation. This computational study provides novel insights and general guidance for interfacial engineering in all-solid-state Li-ion batteries.
Lithium Ion Solvation and Intercalation at Anode-Electrolyte Interface from First Principles
Authors: Ong Mitchell T. , Lordi Vincenzo , Draeger Erik W. , Pask John E.
Published: February 2020

Lithium-ion batteries are commonly used to power many consumer devices such as handheld phones, laptops, portable music players, and even electric vehicles. The interface between the anode and the electrolyte plays a key role in the operation and performance of lithium-ion batteries. In this work, we use first principles molecular dynamics (FPMD) to examine the solvation of the Li ion at different distances from the graphite anode. We find that as Li+ approaches the anode, the coordination number of solvent molecules decreases suggesting that the Li ion must shed its solvation shell entirely to enter the anode. In addition, we estimate the energy required for intercalation of the Li ion into the graphite anode in the presence of the electrolyte. We find that the energy required for intercalation is dependent on the edge termination of the graphite due to electrostatic interactions between Li+ and the terminating species. We further verify the intercalation energy from our FPMD simulations using the nudged elastic band (NEB) method to find the minimum energy paths for entry as a function of different edge terminations. Our results can be utilized to design improved battery systems that optimize Li-ion transport into the anode material.
Multiscale Computational Approaches for the Simulation of Battery Electrodes Fabrication
Authors: Franco Alejandro A. , Shukla Garima , Morcrette Mathieu , Cavalaglio Sebastien
Published: February 2020

The automotive lithium ion battery (LIB) industry has reached a point where optimization studies are vital to achieve high performance at low environmental and economic cost. Significant progress has been made in linking structural properties to ionic transport and cell capacity response using either computer-aided reconstruction of real electrode structure or modeling on built artificial structures [1-2]. However a more holistic approach by combining electrode composition with fabrication parameters is crucial to produce results coherent with experiment. Computational modeling constitutes a powerful tool to establish such an approach, but until now only very few theoretical efforts on this topic have been reported so far [3-4].

In this contribution we aim to mimic standard LIB electrode fabrication techniques through innovative multiscale modelling and numerical simulation [5]. With electrode composition as a control parameter [4,6], respective interactions at the mesoscale level between the active material, conductive material, solvent, binders and dispersants are being considered within an in house three-dimensional Monte Carlo (MC) simulation approach describing the slurry preparation and the solvent evaporation (Figure). The simulations provide insights into the self-organization mechanisms of materials during fabrication as function of the composition, particles size distribution and polymer binder lenght. More specifically, we discuss here the efficiency, advantages and disavantages of using two types of MC methods, namely Metropolis MC and Kinetic MC through the Variables Step Size Method [7-8], on predicting the pore size distributions, porosity and effective electronic conductivity of LIB electrodes.  

The potential of these simulations to lead to proposals of new and highly efficient fabrication techniques is discussed in view of the wide diversity of active material chemistries now emerging for LIB applications.              

[1] A. A. Franco, RSC Adv., 3(2013) 13027.

[2] Stephen E. Trask, Yan Li, Joseph J. Kubal, Martin Bettge, Bryant J. Polzin, Ye Zhu, Andrew N. Jansen, Daniel P. Abraham, J. Power Sources, 259(2014) 233.

[3] Z. Liu, P.P. Mukherjee,  Journal of The Electrochemical Society, 161 
(8) (2014) E3248.

[4] Z. Liu, V. Battaglia, P.P. Mukherjee, Langmuir, 30 
(50) (2014) 15102.

[5] Physical Multiscale Modeling and Numerical Simulation of Electrochemical Devices for Energy Conversion and Storage: From Theory to Engineering to Practice. A.A. Franco, M.L. Doublet, W.G. Bessler (Eds.), Springer (2015). 

[6] G. Liu, H. Zheng, X. Song, V. S. Battaglia J. Electrochem Soc., 159(3) (2012) A214. 

[7] M.A. Quiroga,  A.A. Franco,  J. Electrochem. Soc., 162 (7) (2015) E73.

[8] G. Blanquer, Y. Yin, M.A. Quiroga, A.A. Franco,  J. Electrochem. Soc., 163 (3) (2016) A329.

Figure 1
Image-Based Reconstruction and Statistical Characterization of Li-Ion Battery Electrode Microstructures
Authors: Mukherjee Rajib , Mistry Aashutosh , Mukherjee Partha P.
Published: February 2020

Lithium-ion battery electrodes are composite structures that contain multiple phases including electroactive material, conductive additive and polymer binder. The stochastic microstructure thus formed consists of particulate materials and pore network. The pore scale characteristics of the electrode determine the properties of battery. An accurate estimation of microstructural characteristics is essential for structure property relation that will enable use to design and develop batteries with enhanced properties. With the advancement in X-ray micro-/nano-tomography, details of the electrode microstructure can be probed. Tomographic images of porous electrode microstructures can be obtained at various depths or from different angles. The stack of images needs to be processed for accurate segmentation of pore and particle distribution in the matrix for statistically significant microstructure reconstruction. In the present work, image-based reconstruction of Li-ion battery electrode microstructures and subsequent statistical and transport characterization is presented. In image-based microstructure reconstruction, the segmentation is a critical step that determines the transport networks in the porous matrix. Various algorithms can be employed for segmentation including watershed transform, region merging, graph partitioning. Segmentation methods can be manual, computer assisted or hybrid. In this work, a novel segmentation algorithm has been developed based on region merging method.  The segmentation parameter is determined by the fractal nature of the segments, which in the present case is the pore and active particle interface. This enables the segmentation process to be more accurate and automated. The reconstructed electrode microstructures are characterized by its fractal dimension, which is further linked to the transport properties.
Modeling Battery Performance Due to Intercalation Driven Volume Change in Porous Electrodes
Authors: Garrick Taylor Reed , Dai Yiling , Higa Kenneth , Srinivasan Venkat , Weidner John W.
Published: February 2020

In order to accurately predict the behavior of electrochemical devices, it is necessary to develop sophisticated models that take into consideration transport processes, electrochemical phenomena, mechanical stresses, and structural deformations (i.e. strain) on the operation of an electrochemical system. There are many different models in use that can predict the electrochemical performance of these devices under a variety of operating and design conditions. However, many of these models assume a constant porosity and do not take into consideration the effects of a variable porosity on the porous electrode during cycling and what effects that may have on performance. In recent years, electrodes have been developed that show significant volume changes during intercalation and deintercalation, which are unable to be accurately predicted using these constant porosity models.

Here, a mathematical battery model is presented that incorporates the dimensional and porosity changes in porous electrodes caused by volume changes in the active material during intercalation (e.g., lithium into carbon or silicon). Porosity and dimensional changes in an electrode can significantly affect the resistance of the battery during cycling. In addition, volume changes generate stresses in the electrode, which can lead to premature failure of the battery. Here, material conservation equations were coupled with the mechanical properties of porous electrodes to link dimensional and porosity changes to stresses and the resulting resistances that occur during the intercalation process. The stress-strain relationships used in this model are from previous works, which are used to predict porosity and dimensional changes, and were established by comparing thermal rock expansion and electrode expansion due to intercalation. Several different cases modeled after new battery electrode technologies are examined and operating curves are predicted based off of standard equilibrium potentials.
3D Simulation on the Internal Distributed Properties of Lithium-Ionbattery with Planar Tabbed Configuration
Authors: Cheng Yun , Li Jie , Jia Ming , Du Shuanglong
Published: February 2020

Lithium-ion batteries have promoted the rapid developments of hybrid and electric vehicles due to their high energy, power density, and long lifetime [1]. Meanwhile, advanced hybrid and electric vehicles accelerate lithium-ion cells to be large sized [2].With the increase of battery cell size, the inhomogeneity of battery also increases, which exists not only between the batteries, but also inside a single battery. The inhomogeneity between batteries mainly refers to the difference in the battery pack. The main indicators are inconsistent battery voltage, internal resistance, capacity, and state of charge [3]. This inhomogeneity will lead certain cells to be the state of long-term over-charged or over-discharged, thus not only shortening the battery life, but also even leading to the combustion or explosion of batteries. The inhomogeneity inside a single battery mainly refers to the non-uniform distribution of the electrochemical reaction rate, current density, active material utilization ratio, and the electrolyte concentration in the electrode plate. The main damage of this inhomogeneity is the inhomogeneity of physicochemical properties such as stress gradient on the electrode plate [4]. In long cycling process, large gradient may lead to high diffusion induced stress (DIS), cause particle fracture and reduce battery capacity [5]. The inhomogeneity between batteries can be reduced or eliminated by the automatic production of battery and equalization module of battery management system (BMS). However, the inhomogeneity inside a single battery is difficult to be characterized or measured because of the sealed battery packaging.

In this paper, a validated three-dimensional (3D) model on the electrode plate level of a lithium-ion battery was developed for a commercial type LP12100115 prismatic power LiFePO4/graphite battery (10 Ah) by coupling mass, charge, and energy conservations, as well as electrochemical kinetics. This model can intuitively show the space and time distribution characteristics of the internal electrochemical properties of the lithium-ion battery such as the transient distribution of electric potential, over-potential, state of charge, current density and lithium-ion concentration. The extraction of these distribution characteristics can significantly affect the design and optimization of large lithium-ion batteries.

References

[1] B. Scrosati, J. Garche, J. Power Sources. 2010, 195, 2419-2430.

[2] L. Lu, X. Han, J. Li, J. Hua, M. Ouyang, J. Power Sources. 2013, 226, 272-288.

[3] E. Gallardo-Lozano, M.I. Romero-Cadaval, M.A. Milanes-Montero, J. Guerrero- Martinez, Power Sources. 2014, 246, 934-949.

[4] S. Renganathan, G. Sikha, S. Santhanagopalan, R.E. White, J. Electrochem. Soc.

2010, 157, A155-A163.

[5] C. Lim, B. Yan, L. Yin, L. Zhu, Electrochimica Acta. 2012, 75, 279-287.

Figure 1
First Principles Investigation of the Delithiation Process in Li2s
Authors: Postlewaite Jack , Wawrzyniakowski Zachary , Ma Ying
Published: February 2020

Lithium ion batteries are among the most widely used energy storage devices in consumer electronics. However, limited capacity is still a major problem that hinders their application in a few key markets including electric vehicles. Many different materials are currently under intensive investigation, and lithium sulfide (Li2S) is a promising high capacity cathode material with a theoretical capacity of 1,166 mAh/g that is almost four times higher than what is offered by current commercially available cathodes. The Li2S cathode is also attractive since it can be used with a lithium metal free anode. Unfortunately, the delithiation of Li2S is usually sluggish, and a high charge voltage is required as a result. To understand the associated microscopic mechanism of the delithiation process in Li2S, first principles calculations based on the density function theory are performed using the Vienna Ab initio Simulation Package (VASP). A few low energy Li2S surfaces are created, and the delithiation processes on these surfaces are simulated by extracting a lithium ion on the surface. The resulting energy barriers are recorded and compared, and it is found that different surfaces lead to very different diffusion barriers, suggesting a possible route to minimize the diffusion barrier through the control of the equilibrium shape of the Li2S particles. The structural evolutions for systems with different amount of lithium vacancies that correspond to different percent of delithiation are simulated using ab initio molecular dynamics. To study the possible effects of the electrolyte, these simulations are also performed in the presence of electrolyte. The equilibrium structure of the electrolyte is first determined by ab initio molecular dynamics using a melt-quench process. The Li2S/electrolyte interfaces are then formed and the diffusion barriers are calculated. Three different electrolytes are studied and compared. These calculations provide an atomistic understanding of the delithiation process in Li2S, and help to develop new methods that can be used to minimize the activation barrier of Li2S particles.
Web Based Nano-Materials Design Platform for Li Ion Battery
Authors: Lee Kwang-Ryeol , Lee Min-Ho , Han Sang Soo
Published: February 2020

Owing to the rapid increase in computing power and successful development of the computation methodology, molecular level simulation has driven new paradigm of materials research. We developed web-based materials design platform for Li ion battery, which would significantly reduce the entrance barrier for the multiscale simulation. The platform provides the virtual experiment environment based on the multi-scale simulation technologies ranging from ab initio calculation, molecular dynamics, phase field modeling to continuum simulation. We made the platform to mimic the experimental work flow as closely as possible, which can be distinguished from the existing material design platforms. The platform is composed of 5 modules for the virtual experiments of anode, cathode, electrolyte, solid-electrolyte interface (SEI) and reliability of the materials. In the present talk, the basic concept of platform will be introduced with brief demonstration of the platform. Challenging issues for the progress of the platform will be discussed.

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Simple Design Disposable Non-Enzymatic Glucose Sensor Based on Flexible Ni/PET Electrode
Authors: Molazemhosseini Alireza , Vena Pasquale , Magagnin Luca
Published: February 2020

Since Clark and Lyons explained the basic concepts of glucose enzymatic electrodes, there have been significant efforts on development of reliable devices for diabetes control. This metabolic disorder rooted in insulin deficiency which results in blood glucose concentrations lower or higher than normal range of 4.4 to 6.6 mM. The primary approach to develop electrochemical glucose sensors is to exploit enzymes to oxidize glucose and monitor hydrogen peroxide production. The complications associated with enzyme immobilization and the necessity for maintaining certain operating and storage condition (controlling temperature, pH and humidity) along with the enzymes high cost lead to the development of non-enzymatic glucose sensors (NEG). In NEG sensors, glucose is oxidized directly on electrode surface. In this study, a simple design disposable NEG sensor with high sensitivity and acceptable interference rejection was developed based on NiP/PET electrode. An activation-free Ni electroless metallization was performed using (3-Aminopropyl)trimethoxysilane (APTMS) and (3-Mercaptopropyl)trimethoxysilane (MPTMS) self-assembled monolayers (SAM). The affinity of –HS functional groups on MPTMS-SAM to Ni resulted in a thin film with excellent adhesion. A PMMA mask was used during Ni electroless deposition to obtain a 3-electrode configuration pattern on plastic substrate. Pt electrodeposition was carried out on two of the three Ni electrodes to serve as reference and counter electrodes. Nafion solution was drop-casted on Ni working electrode to reject interference. Electrochemical measurements were carried out in 0.1M KOH solution. 0.5 V was selected as the sensor working potential base on cyclic voltammetry characterizations in presence of glucose. Chronoamperometric measurements presented a wide linear range with high sensitivity of 230 µA.mM-1.cm-2. Results of interference studies proved the accuracy of sensor response in presence of ascorbic acid, uric acid and lactate (less than 15% error which is considered as clinically accurate). The study suggests a low-cost and high performance nonenzymatic glucose sensor compatible with roll to roll manufacturing and mass production.
Pore-Effective Ion Diffusion of Polymer Gel Electrolytes in Sub-Micrometer Porous Electrode
Authors: Ha Su-Jin , Moon Jun Hyuk
Published: February 2020

We estimated the ion diffusion constant of polymer gel electrolytes in sub-micrometer porous electrode. The ion diffusion constant is an important factor which could determine the cell performance. The porous electrode was fabricated by using sub-micrometer polymer colloid crystals as a template. We evaluated the effective diffusion constant in iodine based PGEs and cobalt based PGEs penetrated into the sub-micrometer porous electrodes and compared to that of the nanoporous conventional electrode which was obtained by cyclic voltammetry. The pore-effective diffusion constant of iodine-based polymer gel electrolyte was 6.81 x 10-5 for sub-micrometer porous electrode and 4.78 x 10-6 for the nanoporous electrode. The pore-effective diffusion constant for sub-micrometer porous electrode was enhanced 16% compared to conventional electrode. From this result, the enhancement in pore-effective diffusion was attributed by the sub-micrometer pores. In case of cobalt based electrolytes, the pore-effective diffusion constant was improved 19% by sub-micrometer porous structures as well. In the respect of these results, the pores are demonstrated to assist ion diffusion of polymer gel electrolytes through electrode regardless of redox complex. In particular, the pores are more effective to increase pore-effective diffusion constant under the bulky redox complex electrolytes condition.
Electrochemical Performance and Chemical Stability of Architecturally Designed La2-XPrxNiO4+D IT-SOFC Cathodes
Authors: Sharma Rakesh Kumar , Celikbilek Ozden , Burriel Mónica , Dessemond Laurent , Bassat Jean-Marc , Djurado Elisabeth
Published: February 2020

Solid oxide fuel cells (SOFCs) have attracted widespread attention due to their high energy conversion efficiency and low emissions [1]. The main objective of current research on SOFC is to improve the performance of these devices while operating at Intermediate Temperatures (IT-SOFCs). Both the cathode composition [2] and the microstructural design of the electrode film play an important role in obtaining optimal performances [3, 4]. Porous microstructures with small particle size enhance the catalytic properties by improving the gas distribution and by enlarging the reactive surface area. In this work, architecturally designedLa2-xPrxNiO4+δ films (with x=0.0, 0.5, 1 and 2) have been prepared for the first time by Electrostatic Spray Deposition (ESD) and screen printing (SP). The X-ray diffraction patterns confirm the formation of the pure orthorhombic La2-xPrxNiO4+δ phase in all cases. These novel cathodes consist of an original porous 3D tree-like microstructure sandwiched between a thin dense ESD layer at the electrolyte side and topped by a porous SP layer. The polarization resistance (Rpol) of these La2-xPrxNiO4+δ cathodes was found equal to 0.42, 0.21, 0.11 (Figure 1) and 0.07 W.cm2 at 600°C for x = 0, 0.5, 1 and 2, respectively. These values corresponding to this solid solution are the lowest ones available in the literature to the best of our knowledge. The chemical stability decreases by increasing the Pr content while the Rpol improves. LaPrNiO4+δ is chemically stable up to 30 days at 700°C in air. To conclude, among the La2-xPrxNiO4+δ (0 ≤ x ≤ 2) solid solution, LaPrNiO4+δ shows the best compromise between electrochemical and chemical stability.

Figure 1: Nyquist plot for LaPrNiO4+δ at 600°C in air.                                                                          

References

[1] D. Ding, X. Li, S. Y. Lai, K. Gerdes, M. Liu, Energy Environ. Sci., 2014, (7), 552.

[2] V. Vibhu, A. Rougier, C. Nicollet, A. Flura, J.C. Grenier, J.M. Bassat,
Solid State Ionics, 2015, (278), 32.

[3] D. Marinha, L. Dessemond, E. Djurado, J. Power Sources, 2012, (197), 80.

[4] R. K. Sharma,   M. Burriel    E. Djurado, J. Mater. Chem. A, 2015, (3), 23833.

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In Situ Raman Studies on Electrochemically Deposited Manganese Oxide on Gold
Authors: Pavlovic Zoran Miroslav , Ranjan Chinmoy , Gao Qiang , Schloegl Robert
Published: February 2020

Water oxidation is one of the biggest challenges towards establishing a sustainable energy economy based on renewable energy. Non noble metal electrocatalysts can significantly reduce the costs and make usage of electrochemical water splitting on a large scale possible. Those metal oxide catalysts can be an effective replacement even if their electrochemical activities are a fraction of noble metal oxide catalysts. If these catalysts can be developed on such a way that their operational lifetime would become comparable to noble metal materials, problem of electrochemical water splitting would be partially solved.

MnO2-x naturally exists in various polymorphs with various amounts of defects. Each of them has different electrocatalytic performance. Poor electronic conductivity, which is very important for good water splitting catalysts, is also one of the issues with these materials. These catalysts remain a long way from successful implementation within electrolysers, even with enormous potential of usage. It is important that these materials are studied in situ in order to understand performance and limitations under the operando conditions.  

In situ Surface Enhanced Raman Spectroscopy is used to track the structural changes of the lattice of hydrous MnOx, while sweeping the potential in the range of 0 - 2.2 V vs RHE. MnOx catalyst is prepared by electrochemical deposition on the surface of roughened gold. It was done by passing an anodic current of 50 mC/cm2 at 1.6 V vs RHE in 0.5 M MnSO4 solution. By following the Mn-O-Mn stretching at various potentials in various electrolytes, the structural conformation of the catalyst was studied. For each electrolyte a unique catalyst structure was finally established. Various electrolytes (alkaline, neutral and acidic)  containing alkali metal ions (Li, Na, K, Cs), alkaline earth metal ions (Ca, Sr, Ba) and anions such as borates, phosphates and sulphates were used to study OER under in situ Raman conditions. Catalysts were also studied under conditions of duteration of the electrolytes.

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Quantification of Phase Evolution in Praseodymium Nickelates
Authors: Dogdibegovic Emir , Wright Christopher J. , Zhou Xiao-Dong
Published: February 2020

A new method to quantify the phase evolution in nickelates is developed using sintered metal grids as cathode current collectors. The metal grids not only enable us to carry out phase quantification studies in cathodes, but also retaining the cell’s performance and stability. Moreover, they are chemically compatible with the cathode and allow XRD analysis of the surface and bulk of the cathode after cell operation. Multiple cells were tested to study the reproducibility of measurements. High performance was observed in cells with metal grids, extending the application of this method to cathode durability studies in state-of-the-art SOFCs.  Respective advantages and challenges of the method are discussed with an emphasis on phase quantification, and the effects of different noble metals in cells regarding their thermal, electrical, chemical, and mechanical stability. Au was found to be the most suitable current collector due to its low chemical reactivity with the cathode and mechanical compatibility at operating conditions.