bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrolyte Solvent Mixtures for a Symmetric, Non-Aqueous Redox Flow Battery Based on [Fe(bpy)3][Fsi]2
Authors: Blesch Thomas , Cabral Diogo Moulin , Howlett Patrick C , MacFarlane Douglas R.
Published: February 2020

Redox flow batteries (RFBs) store energy in liquid redox-active electrolytes which are charged and discharged while flowing through an electrochemical cell. This separation of storage and reaction sites enables flexible scalability of power and energy density. [1] Research suggests that non-aqueous RFB systems offer a promising combination of cost and performance for stationary applications, such as storage of excess renewable energy from domestic- to grid-scale [2].

In this work, we investigate a RFB based on the iron(II)-tris(2,2’-bipyridine) bis(fluorosulfonyl)imide complex, which shows one metal-centred oxidation process and up to three ligand-centred reduction processes, providing 2.4 V cell potential [3]. Using the same active material on both positive and negative sides of the cell mitigates the detrimental effects of cross-over through the separator membrane.

These redox processes are solvent-dependent [3] and their electrochemistry was studied in a range of aprotic single and mixed solvents, some already used in lithium-ion batteries [4]. Since energy density is determined by the cell potential and the concentration of the active material, the solubility of the reduced and oxidated states of the complex was examined by UV/vis spectroscopy. Furthermore, conductivity and viscosity were measured over a range of temperatures. In RFBs, the dynamic viscosity of the electrolyte influences not just the conductivity but also affects the power required to pump the electrolyte. Cost, safety and environmental impact were considered as well.

References:

[1] L. F. Arenas, C. Ponce de León, F. C. Walsh, J. Energy Storage
2017, 11, 119-153.

[2] R. Dmello, J. D. Milshtein, F. R. Brushett, K. C. Smith, J. Power Sources
2016, 330, 261-272.

[3] D. M. Cabral, P. C. Howlett, D. R. MacFarlane, Electrochim. Acta
2016, 220, 347-353.

[4] K. Xu, Chem. Rev. 2004,
104, 4303-4417.

Figure 1
Neutron Imaging at the ILL for Li-Ion Battery and Fuel Cell Research
Authors: Atkins Duncan
Published: February 2020

NeXT-Grenoble is a Neutron and X-ray Tomography facility developed and now running in Grenoble, born from a collaboration between the University Grenoble Alpes and the European Neutron Source the Institut Laue-Langevin (ILL). This instrument combines the uniquely intense neutron flux offered by the ILL with laboratory X-ray tomography in order to obtain bi-modal imaging, thus taking advantage of the reciprocal benefits of each respective method.

As a preliminary step, a medium resolution neutron radiography/tomography instrument was implemented in 2016 allowing users to perform successful material characterisations in a wide range of applications such as Li-batteries, proton-exchange membrane fuel cells, porous/geomaterials and medical prosthetics. The specific transmission proprieties of neutrons (low attenuation of metals compared with relatively high absorption in light elements such as lithium and hydrogen, and isotopic differentiation, e.g., between 6Li and 7Li or 1H and 2H) and the high flux of ILL’s reactor is now enabling researchers to take this type of tomographic set-up to its limits in terms of the inherent compromise between temporal and spatial resolution.

In order to exploit the complimentarity of neutron and X-ray imaging, a laboratory X-ray ensemble has been integrated (see Figure 1) and is operational since 2018, along with an ensemble of high resolution neutron detectors. This has made possible for the first time full visualisation of in operando interactions between complex phenomena, notably in the domains of battery and hydrogen fuel cell research – examples of which will be shown here.

Figure 1
Improved Electrical Performance By Separating Enzymes By Agarose in Bi-Enzyme Electrode for Biofuel Cells
Authors: Wang Xue , Seo Yang Gon , Kim Hyug-Han , Kim Chang-Joon
Published: February 2020

Equipped with tiny sensors, insects can scout out buildings filled with noxious chemicals, check under rubble after an earthquake and go places no human spy over could. Power source is required to power the electronics attached to insects. Recently, insect-mountable enzyme fuel cells (EFCs) have been presented, which utilize trehalose, the main sugar of insect hemolymph. The anode system composes of two enzymes, glucose oxidase (GOD) and trehalase (THL), and enzyme mixture was used for fabrication of anode in reported EFCs. In this study, however, we demonstrated that THL prevented electron transfer from enzyme layer to electrodes and separating it from GOD can improve the performance of bi-enzyme electrode. Here, two enzymes were immobilized on gold electrode by physical adsorption and they were separated by agarose gel. Osmium-based polymers were used as electron transfer mediators. The optimal concentration of agarose was determined. The effects of GOD-Os layer and THL loading were examined. The performances were compared for electrodes with or without single walled carbon nanotubes (SWCNTs) in the GOD layers. The electrical properties were measured using electrochemical impedance spectroscopy and cyclic voltammetry. The cell performance was evaluated with optimized anode and cathode covered with bilirubin oxidase. The maximum power density was 1.23 ± 0.04 mW/cm2.
Investigating the Internal Processes of Thermo-Electrochemical Cells Using in-Situ Magnetic Resonance Imaging
Authors: Gunathilaka Isuru Eranda , Taheri Abuzar , Pringle Jennifer M , Forsyth Maria , O'Dell Luke
Published: February 2020

Thermo-electrochemical cells are emerging as a promising and efficient method to convert waste heat to electricity. In addition to developing novel redox electrolyte materials to increase the energy densities, it is crucial for future developments to understand the internal chemical and thermodynamical processes happening inside the thermo-electrochemical cell while it is under operating conditions. Although the temperature and concentration distributions between the electrodes and the variations of the convection currents with cell orientation have been modelled mathematically, it has been a challenge to study these internal processes using experimental techniques.

Magnetic resonance imaging (MRI) is a non-invasive and well-established diagnosis technique in medical research to investigate physiology, but it also has the capability to study spatial properties of materials, chemical and thermodynamic processes in energy storage devices using different image contrast options including spin density, relaxation time and velocity [1]. The goals of this study are to develop an MRI method to study the internal chemical and thermodynamic processes within a functioning thermo-electrochemical cell, and understanding how these are affected by the electrolyte, the cell geometry and the orientation of the thermal gradient. A cobalt redox couple based electrolyte, which has been shown to be a promising candidate for thermo-electrochemical cells [2], was used for the in-situ experiments inside specialised cells custom built for MRI experiments, and temperature and concentration dependent 1H nuclear magnetic resonance spin-lattice relaxation time (T1) measurements were used to interpret the 1H T1 weighted MRI images of the working cells.

References

[1] Britton M. M., MRI of chemical reactions and processes, Progress in Nuclear Magnetic Resonance Spectroscopy, 101 (2017) 51-70.

[2] Dupont M. F., MacFarlane D. R., Pringle J. M., Thermo-electrochemical cells for waste heat harvesting – progress and perspectives, Chem. Commun., 53 (2017) 6288-6302.
High Voltage Window of the Symmetrical Electrochemical Capacitor Made By Using Dual Redox Additives Enhanced Quasi-Solid like Electrolyte
Authors: Chiu Chun-Kai , Yang Chih-Chieh , Kumar Amit , Pattanayak Bhaskar , Tseng Tseung-Yuen
Published: February 2020

Recently, researchers have shown an increased interest in redox-active electrolyte because of its high performance and simple fabrication. However, most studies have only focused on aqueous electrolyte system, while suffering from limiting potential window of the electrochemical capacitor(EC) due to water decomposition voltage at 1.23 V. In addition, leakage problem results in safety concern in liquid system.

In the light of this, we introduce dual redox additives TEMPO and pBQ into PVDFHFP-BMIMTFSI-EC quasi-solid like polymer electrolyte (QSPE) as dual redox active electrolyte (RQSPE). The TEMPO and pBQ enable rapid charge transfer and highly solubility in ionic liquid, promoting the synergic effect of electric double layer capacitance(EDLC) and redox reaction. The coupling of battery-like reversible redox reaction and supercapacitor-like EDLC leads to provide high energy density and power density at the same time. The electrochemical properties of the fabricated EC involving RQSPE electrolyte and carbon electrodes are compared to those of the EC using QSPE without redox additives. The excellent specific energy of 61.12 Wh kg-1 is exhibited by the EC with RQSPE, which is over three times higher than the one without redox additives. In addition, the specific power density of the EC with RQSPE is up to 3.43 kW kg-1 at 17.10 Wh kg-1. Furthermore, the addition of redox additives can expand the voltage window of the EC to 3 V, while the EC without such additives has less value of 2.5 V. The ionic conductivity of the electrolyte is 8.85 mS cm-1, also indicating that adding redox additives have positive effect to the mobility of electrolyte. Finally, the EC with RQSPE exhibits stable cycling stability over 2000 charge/discharge cycles.

Figure 1
On Methanol Electrochemical Oxidation at Platinum-Bismuth Binary Catalyst
Authors: Alsaidi Walaa Saad , Awad Mohamed
Published: February 2020

The electrochemical behavior of methanol on a binary catalyst composed of platinum and bismuth nanoparticles electrodeposited consecutively onto a pre- electro-activated glassy carbon electrode has been investigated. Either platinum was deposited first followed by bismuth or the reverse. The modified electrodes were morphologically characterized using scanning electron microscopy and their composition were probed using energy dispersive x-ray. The crystallography of the thus deposited nanoparticles was explored using XRD. Modified electrodes, i.e., Pt/Bi/GC (Bi deposited first) and Bi/Pt/GC electrodes (Pt deposited first) were electrochemically characterized using cyclic voltammetry and chronoamperometry.

It has been found that the electrocatalytic activity critically depends on the order of the deposition of platinum and bismuth. The Pt/Bi/GC electrode showed a larger electrocatalytic activity towards methanol oxidation compared to Bi/Pt/GC electrode. The higher activity obtained at the former electrode is attributed to the cooperative effect of Pt and Bi towards methanol oxidation.

Keywords: Platinum nanoparticles, bismuth, Electrodeposition, Methanol electro-oxidation.
Rapid Lab Grown Biofilm As a Tool for Engineering Sensor Networks of Biofouling-Resistant Electrochemical Sensors
Authors: Raditya Aldyla , O'Hare Danny
Published: February 2020

Robust and rapid biofilm formation is not only a major interest in the development of microbial fuel cell, but it is also be of relevance to the development of indwelling environmental sensor networks. Sensor networks offer real-time, online and long-term monitoring which is an attractive monitoring strategy for water industry to prepare for increasing demand for clean water due to increased urbanisation and the pressures of climate change. Sensor networks support the development of robust and managed drinking water supply networks that are essential to human health.

Fouling of sensors due to biofilm formation is very common in indwelling situations and it is a major drawback in the development of sensor networks. Sensors will fail once it is fouled and it can happen in just a couple days or weeks. Engineering robust sensor networks begins with designing a biofouling resistant sensors. Electrochemical sensors are inexpensive and simple to construct and operate, and it is widely used in water industry. Understanding how biofilms affect electrochemical sensor performance is important to enable detection of malfunction in situ, and can inform the development of methodology to restore the performance in situ. Networks can consist of hundreds of sensors and automated restoration of function in biofouled sensors is thus essential.

Lab-based models play a vital role. However, it is not always possible to recreate the real conditions for biofilm formation in the lab and it can take too long for it to form. In a situation in which it is not possible to build a permanent testing setup, rapid lab grown biofilm is desirable.

Adhesion of pioneering bacterial cells to the surface is the most crucial step in biofilm formation. Adhesion of cells to surfaces can be accelerated by altering the surface chemistry of the surfaces. One way to do this is by plasma treatment of the surface. Formation of a lawn of biofilm is desirable to model early biofouling event. Polysaccharide production that forms the extrapolymeric substance (EPS) of biofilm can be induced by common biocidal substance such as triclosan. Electrochemically generated local concentration of hydrogen peroxide has similar consequences. In this work, we show that it is possible to form some coverage of biofilm on electrode surface in just two hours, which represents early biofouling event. It has a potential for the development of rapid lab grown biofilm that can be useful in developing fail-proof sensor networks.
High-Performance Micropore- and Mesopore-Rich Activated Carbon in Ionic-Liquid Electrolyte
Authors: Patra Jagabandhu , Lai Hong -Zheng , Chang Tseng -Lung , Chang Jeng-Kuei
Published: February 2020

Electrolyte optimization plays a key role in deciding energy density (ED) and power density (PD) of supercapacitors. Increasing cell voltage is an effective way to improve ED and PD. Therefore, an electrolyte with a large potential window is highly desired. Ionic liquid (IL) electrolytes, characterized by wide potential windows, excellent thermal stability, intrinsic ionic conductivity, non-volatility, non-flammability, and low environmental concerns, are potential electrolytes and are used for micropore-and mesopore-rich activated carbon (ACmicro and ACmeso) supercapacitors. IL electrolytes consisting of various cations of EMI+ (1-ethyl-3-methyl imidazolium), PMP+ (N-propyl-N-methyl pyrrolidinium), and BMP+ (N-butyl-N-methyl pyrrolidinium) and various anions of TFSI– (bis(trifluoromethyl sulfonyl) imide), BF4
– (tetrafluoroborate), and FSI– (bis(fluorosulfonyl)imide) are explored. The electrolyte viscosity and conductivity and ion transport properties at the ACmicro and ACmeso electrodes are studied. Also, the capacitance, cycling stability, and rate capability of the ACmicro and ACmeso electrodes are systematically investigated, and post-mortem material analyses are conducted. This study shows the influence of IL composition on charge–discharge capacitances of the ACmicro electrodes is more pronounced than that for the ACmeso electrodes. The FSI-based IL electrolytes, whose electrochemical properties are dependent on cation, are found to be highly promising. Uniting EMI+ with FSI– results in low viscosity of electrolyte and high ion transport, optimizing the electrode capacitance and rate capability. Interchanging EMI+ with PMP+ enhances the cell voltage (to 3.5 V) and maximum ED (to 42 Wh kg−1) of the ACmicro cell at the cost of cycling stability.
Lattice Analysis By Synchrotron Powder Diffraction on High Voltage Spinel LiNi0.5Mn1.5O4
Authors: Seidel Matthias , Nikolowski Kristian , Auer Henry , Kinski Isabel , Wolter Mareike , Mikhailova Daria , Maletti Sebastian , Michaelis Alexander
Published: February 2020

The high voltage spinel LiNi0.5Mn1.5O4 (LNMO) is a promising material to increase the energy density of lithium ion batteries. A variety of research was done to investigate the material regarding its properties, synthesis and commercial viability. To investigate in detail the properties of the cathode material during the delithiation and lithiation, in situ measurements are a helpful tool to fully understand changes in the crystal structure, which can give important information how to further improve the electrochemical properties of the cathode material. Especially the ‘ordered’ crystal phase P 4332 and the ‘unordered’ F d¯3
m, which can result from different temperature treatments during the synthesis process, need to be investigated to define the correlation between calcination temperatures, lattice parameters and electrochemical properties.

The LNMO investigated was synthesized using a spray drying method. From a solution of acetate and nitrate salts precursors were produced which have been calcined under different conditions to support the crystallization into the ordered and unordered phase, respectively. First, the two powders were characterised by SEM analysis to investigate the crystal morphology. Then slurries (LiNi0.5Mn1.5O4, PVDF binder, carbon, NMP solvent) were prepared and cast on aluminium foil to prepare electrodes. The electrochemical properties of assembled test cells (capacity, cycle life, etc.) were measured. Customized coin cells were used for the in situ measurements. The in situ XRD were measured using the high energy, low-emittance synchrotron radiation source at the Petra III beamline P02.1 at the DESY in Hamburg. 1

In our presentation we will correlate the synthesis temperatures, electrochemical properties and lattice parameters for the synthesized LNMOs. By deeply analysing the in situ measured diffraction patterns for the different state of charge we will fully demonstrate the phase transition for the different samples and correlate the lattice change to properties like the manganese(III) amount and the crystal phase (figure 1). The manganese(III) amount is mostly dependent on the calcination temperature and therefore also on the received crystal phase. Furthermore, we will outline the influence on the degradation for the different samples. The degradation differences between the synthesized samples were investigated by analysing the cumulative charge and discharge capacity. 2 The combination of those results will lead to a deeper understanding of the connection between the different influence factors for the cathode material.

References

A.-C. Dippel, N. Bindzus, D. Saha, J. T. Delitz, H.-P. Liermann, N. Wahlberg, J. Becker, E. D. Bøjesen and B. Brummerstedt Iversen, Z. Anorg. Allg. Chem.,
640(15), 3094–3099 (2014).

A. J. Smith, J. C. Burns, D. Xiong and J. R. Dahn, J. Electrochem. Soc.,
158(10), A1136 (2011).

Figure 1
New Class of Solid State Electrolytes for Batteries: Correlating Structure to Functional Properties
Authors: Sen Sudeshna , Gregory Duncan
Published: February 2020

Growing energy demand and depletion of fossils fuels results in requirement of electrochemical devices with high energy density, smart miniaturisation to store energy in lower area. These are coupled with safety concern which is mitigated via replacement of liquid electrolytes with polymeric and solid-state electrolytes. Exploration of novel class of electrolytes with good ionic conductivity, high thermal stability and mechanical integrity not only address safety concern of devices but also adds up possibility of exploring new processing technology. In this regard, we demonstrate here a new class of borohydride-based ion conductors based on bimetallic anion-substituted borohydrides, as a potential solid-state electrolyte. The pertinent structure-property relationships will be discussed as a function of structural parameters (metallic substitution, anionic substitution and doping) of the solid like electrolytes. They show appreciable ionic conductivity (σ ~10-4 S cm-1 at 298 K) and and wide electrochemical window, pertinent to the battery application. Preliminary electrochemical results on solid state battery assembly will be presented briefly. The solid-state electrolyte work will be coupled with soft material-based electrolytes as potential electrolyte/lithium protecting layers will also be discussed in application of lithium based solid state batteries. A special attention will be given to fundamental transport properties and correlating the key physical design strategies of new ionic conductors to their physico-chemical properties.
In-Situ Measurement of Distribution of Lithium Atoms in Li-Ion Batteries and Their Components Using Thermal Neutron Beam
Authors: Tomandl Ivo , Vacík Jiří , Horák Pavel , Sierra Yesid Mora , Kobayashi Takane
Published: February 2020

Nowadays, rechargeable Li-ion batteries are widely used in various devices. The further development of these secondary batteries depends on investigation of new materials for electrodes, electrolyte and interphases. The many physical or electrochemical methods, e.g., x-ray diffraction, x-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), can evaluate or investigate various aspects of these materials. Nevertheless, none of these methods can provide experimental spatial distribution of lithium atoms within full cell, half cell or some prospective materials. This very important information can be supplemented by nondestructive nuclear analytical technique, Neutron Depth Profiling (NDP) [1]. This unique technique is based on irradiation of samples by an intense beam of thermal neutrons and analyzing the energy loss of charged particles following the 6Li(n,α)3T reaction. The high nominal resolving power (depth resolution) of this method, about 10 nm, charge neutrality of neutron beam and high cross section of the capture reaction, 940 b, enable various in-situ measurements in various electrochemical conditions. Beside traditional NDP technique the above mentioned reaction can be exploited for high resolution imaging of 2D distribution of lithium in thin samples [2]. The both method capability for investigation of Li-ion battery samples will be discussed and examples of usage will be presented in this contribution.
Step Potential Electrochemical Spectroscopy (SPECS) As a Means of Examining the Behaviour of Electrochemical Systems
Authors: Donne Scott W
Published: February 2020

Electrochemical energy storage and conversion devices play a substantial and growing role in society. The study of these systems has likewise continued to grow with significant efforst ongoing globally to develope new and improved materials and systems for consumer use. The basis of a significant proportion of this effort are fundamental material characteristics, as evaluated using a suite of physico-chemical and electrochemical characterization methods.

Electrochemically, characterization of such systems is typically based on techniques such as cyclic voltammetry and galvanostatic charge and discharge which provide a solid foundation for material and device performance evaluation. Of course the application of these methods to controlled electrodes allows for the initial characterization of electrochemical behaviour. Electrochemical impedance spectroscopy also plays a role in material and system characterization, albeit under very specific conditions.

Here we report on the application of an intermittent discharge and charge methodology, step potential electrochemical spectroscopy (SPECS), in particular its application to separating charge storage mechanisms in electrochemical systems, as well as its combination with additional electrodes and electrochemical techniques to elucidate behaviour.
Elemental Analysis of Aging Effects in Lithium Ion Batteries By Means of Laser Ablation-Inductively Coupled Mass Spectrometry
Authors: Harte Patrick , Mense Maximilian , Winter Martin , Nowak Sascha
Published: February 2020

As the performance of the lithium ion battery (LIB) technology is rising constantly, one of the major challenge remains in the form complex aging phenomena, affecting crucial properties such as cycle life, capacity fade and safety.1 In order to improve the electrochemical performance of LIBs, by preventing or reducing aging effects, a deeper understanding of the degradation of battery materials and factors influencing these processes is needed.

Spatial and depth resolved elemental information allows for the study of different processes, such as transition metal dissolution (TMD) and subsequent deposition on the anode surface, as well as loss of active lithium (e.g. through deposition in the solid electrolyte interface (SEI), lithium plating).2 Established techniques for these investigations include time of flight-secondary ion mass spectrometry (ToF-SIMS) and Glow discharge-optical emission spectroscopy (GD-OES). However, small spot sizes, prolonged measurement times or the inability to provide spatial resolved information limit the applicability of these techniques. Laser ablation-inductively coupled mass spectrometry (LA-ICP-MS) offers the unique combination of spatial and depth resolved information, excellent limits of detection, fast measurement times (even for large samples) and easy sample preparation.

Therefore this work deals with the application of LA-ICP-MS as a direct solid sample analysis technique for the investigation of the degradation of LIB electrode materials. Mapping experiments are carried out to visualize deposition patterns of lithium and transition metals as well as study factors influencing these depositions.

(1) Vetter, J.; Novák, P.; Wagner, M. R.; Veit, C.; Möller, K. C.; Besenhard, J. O.; Winter, M.; Wohlfahrt-Mehrens, M.; Vogler, C.; Hammouche, A. Ageing Mechanisms in Lithium-Ion Batteries. J. Power Sources
2005, 147 (1–2), 269–281.

(2) Schwieters, T.; Evertz, M.; Fengler, A.; Börner, M.; Dagger, T.; Stenzel, Y.; Harte, P.; Winter, M.; Nowak, S. Visualizing Elemental Deposition Patterns on Carbonaceous Anodes from Lithium Ion Batteries: A Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Study on Factors Influencing the Deposition of Lithium, Nickel, Manganese and Cobalt after Dissoluti. J. Power Sources
2018, 380 (January), 194–201.
Combining Operando Techniques to Identify Challenges in Graphite Composite Negative Electrodes for Sulfide Based Solid-State Lithium Batteries
Authors: Hoeltschi Laura , Jordy Christian , Boillat Pierre , Cochet Magali , Villevieille Claire
Published: February 2020

All-solid-state batteries are attracting growing attention as they have the potential for enhancing safety and electrochemical performances compared to conventional organic based batteries. Until now, among the available solid electrolytes, the sulfide based materials have presented the most interesting properties in terms of ionic conductivity and cold-pressing. Nevertheless, from DFT calculations it has been shown that their thermodynamic stability window is rather limited (lower than 1V) [1]. Chemical/electrochemical instabilities of the solid electrolytes towards graphite and high-voltage cathode materials are therefore reported. Currently, graphite is the state-of-the-art material for the negative electrode in commercial batteries because of its solid electrolyte interphase (SEI) stability, which allows graphite to be cycled with high capacity for a very long time and without significant fading. Unfortunately, its interfacial reaction with solid electrolytes is still unclear [2] [3]. The aim of this study is to identify the main parameters which need to be optimized to make the graphite electrode potentially viable in solid-state batteries in the near future.

First, the electrochemical performance of two electrolytes Li2S-P2S5 and LiI-Li2S-P2S5 have been tested in combination with graphite as composite negative electrode (50:50 wt.% ratio). Graphite materials with different particle sizes, surface areas and morphologies have been tested in a half-cell with a Li-In counter electrode. Long term cycling data of graphite with a sulfide-based electrolyte are depicted in Figure 1A. Afterwards, advanced operando techniques were employed to understand the capacity fading mechanism of graphite.

X-ray Tomography revealed initial cracks in the composite graphite electrode during the construction of the electrochemical test cell (see Figure 1B). Operando XRD showed that the graphite was not fully lithiated even during the first lithiation. Moreover, operando Neutron Imaging indicated that the electrode was more lithiated close to the separator than close to the current collector.

References

[1] Y. Zhu, X. He, Y. Mo, ACS Applied Materials and Interfaces 7, 23685-23693 (2015).

[2] K. Takada, T. Inada, A. Kajiyama, H. Sasaki, S. Kondo, M. Watanabe, M. Murayama, R. Kanno, Solid State Ionics 158, 269-274 (2003).

[3] Y. Kato, S. Shiotani, K. Morita, K. Suzuki, M. Hirayama, R. Kanno, Physical Chemistry Letters 9, 607-613 (2018).

Figure 1
Application of Solid State Nuclear Magnetic Resonance in Energy Storage Systems
Authors: Frerichs Joop Enno , Haneke Lukas , Li Meirong , Stan Marian Cristian , Winter Martin , Placke Tobias , Hansen Michael Ryan
Published: February 2020

Since Sony introduced the Lithium Ion Battery (LIB) in 1991, an enormous effort has been made to further improve the performance of this battery system[1-2]. Nowadays, the research in LIBs is driven by the transition from combustion-based transportation to electric engines and the global energy revolution[3-5]. Environmental friendly cell chemistries are thus of particular interest in terms of recycling and safety reasons, especially for storage of renewable energies. In this connection, dual-graphite batteries receive increasing attention due to the use of graphitic carbon for both the negative and positive electrodes, i.e., free of transition metals[6]. A prerequisite for further improvements is clearly the understanding of the ongoing chemistry in these complex systems. In the last years, solid-state Nuclear Magnetic Resonance (NMR) has proven to be a very powerful technique for the investigation of the underlying chemistry of a vast number of materials used in LIBs[7-8]. Since NMR is not restricted to crystalline samples also highly disordered and amorphous materials can be studied. Furthermore, solid-state NMR provides quantitative measurements, is chemically specific and therefore extremely suitable for the investigation of the electrochemical processes in battery systems[7-8]. Also, the recent development of in situ or in operando measurements makes it highly beneficial for battery research[7-9]. In this contribution, we present the (i) first 119Sn NMR spectroscopic characterization of the Li-Sn system for the subsequent determination of Sn-containing battery materials, (ii) in operando determination of high surface area lithium (HSAL) on lithium metal electrodes, (iii) investigations of the charge/discharge mechanisms in S/PAN, and finally (iv) insights in the anion intercalation in dual-graphite cells.

References:

[1] J. Cabana, L. Monconduit, D. Larcher, M. R. Palacín, Advanced Materials
2010, 22, E170-E192.

[2] G. E. Blomgren, Journal of The Electrochemical Society
2017, 164, A5019-A5025.

[3] M. V. Reddy, G. V. Subba Rao, B. V. R. Chowdari, Chemical Reviews
2013, 113, 5364-5457.

[4] D. Andre, S.-J. Kim, P. Lamp, S. F. Lux, F. Maglia, O. Paschos, B. Stiaszny, Journal of Materials Chemistry A
2015, 3, 6709-6732.

[5] B. Scrosati, J. Garche, Journal of Power Sources
2010, 195, 2419-2430.

[6] T. Placke, A. Heckmann, R. Schmuch, P. Meister, K. Beltrop, M. Winter, Joule
2018, 2, 2528-2550.

[7] O. Pecher, J. Carretero-González, K. J. Griffith, C. P. Grey, Chemistry of Materials
2017, 29, 213-242.

[8] S. Haber, M. Leskes, Advanced Materials
2018, 0, 1706496.

[9] S. A. Kayser, A. Mester, A. Mertens, P. Jakes, R.-A. Eichel, J. Granwehr, Physical Chemistry Chemical Physics
2018, 20, 13765-13776.
Electrode, Electrolyte and Architecture Assessment for High Power Thin Film Microbatteries
Authors: McGrath Louise M , O'Donoghue Aaron , Clancy Tomas , Burke Micheal , Rohan James F.
Published: February 2020

Silicon integrated on-chip energy storage is an attractive goal for hybrid power sources coupled with energy harvesting for ‘Internet of Things’ devices and applications. Typical thin film microbatteries are limited to low power and energy outputs in the 2D planar formats. One of the issues with solid-state thin film microbatteries is the high resistance of the electrolyte which can lead to significant potential drop when powering devices during sensor operation and communication. The ability to provide high currents in a small form factor is a critical need for the development of realistic long life devices.

In this work we will describe the use of Comsol finite element simulations to assess electrode materials, appropriate electrolytes and optimised architectures for improved microbattery power outputs. The simulations were of a microbattery stack where non-porous additive-free LiCoO2 is the cathode, lithium metal is the anode and solid-state, polymer, polymer-gel and liquid electrolytes were investigated. The simulations show the material utilisation and overall electrochemical cell behaviour of Li-ion electrode materials at typical and high power rates. Core-shell structures based on nanoarchitectures for electronic contact and active electrode materials have been investigated to improve power delivery for nanoscale active materials and for low conductivity oxide cathodes.

The simulations indicate that the implementation of nanoarchitectures such as 3D and 3D core-shell nanoarchitectures when coupled with the appropriate electrolytes and interfacial reactions can have a significant advantage in terms of areal energy and power capabilities compared to a thin-film geometry for a microbattery cell. The deployment of these architectures for microbatteries where area is at a premium and high power capabilities are desirable should result in better performing hybrid energy and less complex power management systems.

Acknowledgments

The authors would like to acknowledge the financial support from Science Foundation Ireland (SFI) Grant number: 12/IP/1722, Nanomaterials design and fabrication for energy storage. This work is supported in part by a research grant from SFI co-funded by the European Regional Development Fund under Grant Number 13/RC/2077. This work is also supported in part by a research grant from the EU Horizon 2020 work programme – Enables, European Infrastructure Powering the Internet of Things, project number 730957.
Photoelectrochemical and Surface Analysis of CdSe-Poma Composites on Highly Organized Pyrolytic Graphite
Authors: Dulovic Stephanie , Casto Sophia Maria , Widera Justyna , Maranowski Bartosz , Strawski Marcin , Szklarczyk Marek
Published: February 2020

Over the past decade, semiconductors have been of great interest and currently found applications in computers, cell phones, and medical equipment. Semiconductors provide the basis for the operation of a solar cell in the study of the conversion of solar energy into electricity.

This study intended to analyze the stability and efficiency of semiconductor hybrid composites containing cadmium selenide (CdSe) and poly(o-methoxyaniline) (POMA), in the presence of light. The deposition of the CdSe-POMA composites was performed through electrochemical cycling on highly organized pyrolytic graphite (HOPG) surfaces. The composites differed in the order, in which the two components were deposited: (1) CdSe before POMA (CdSe/POMA), (2) POMA before CdSe (POMA/CdSe), and (3) CdSe and POMA simultaneously (CdSe+POMA). The CdSe/POMA and POMA/CdSe composites were deposited in their respective orders, with CdSe layer deposited for 20 cycles via cyclic voltammetry from the solution containing 5 mM CdSO4 and 1 mM SeO2 in 0.1 M HClO4, and POMA film polymerized for 5 cycles from the solution containing 0.06 M o-anisidine in 0.1 M HClO4. The deposition of CdSe+POMA was performed for 20 cycles via electrochemical cycling in the solution of 5 mM CdSO4 + 1 mM SeO2 and 0.06 M o-anisidine in 0.1M HClO4.

The photoelectrochemical studies of the created composites consisted of cyclic voltammetry, open circuit potentiometry and chronoamperometry were performed in the 0.1M Na2SO3 solution. The composite of CdSe/POMA presented the greatest photopotential around 220 mV, while POMA/CdSe (30 mV) and CdSe+POMA (14 mV) showed much smaller photopotential values. The chronoamperometric studies found that CdSe/POMA had the greatest photocurrent density of 17 μA/cm2, while POMA/CdSe (0.05 μA/cm2) and CdSe+POMA (0.42 μA/cm2) had substantially smaller photocurrent density. The POMA/CdSe and CdSe+POMA composites proved to be less stable and less photo-active. Following photostudies, the surface morphology and composition of these hybrids were analyzed using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The surface analysis found a greater degree of degradation of the other two composites (POMA/CdSe, CdSe+POMA), indicating that the polymer deposited above the CdSe layer in the CdSe/POMA composite may be crucial in lessening the degree of degradation resulting from the photo-exposure.
Modeling the Origin of the Interface Resistance in Solid-State Batteries
Authors: Qi Yue , Swift Michael , Tian Hong Kang
Published: February 2020

The major bottleneck for the all-solid-state batteries lies at the high interfacial resistance, which is due to two main factors, physical contact and chemical effect, both will be evaluated via modeling in this talk.

First, we devise a model, incorporating atomic electrochemical potentials, thermodynamic stability of bulk electrolyte phases, and point defect formation energies to yield quantitative profiles of the electrostatic potential, lithium chemical potential, and electronic energy levels. This model complements direct microscopic and macroscopic simulations by rigorously and simultaneously determining the potential drop, electrostatic dipole, and space-charge layer at the interface. The application of this model to the Li/LiPON/LixCoO2 system leads to the important discovery that the space-charge layer varies with the state of charge (i.e. Li concentration in LixCoO2). This new physics insight unifies the seemingly contradictory experimental observations and leads to new device design rules to promote interfacial ion transport in future SSBs.

Secondly, we combined contact mechanics with 1D Newman battery model to capture the effect of imperfect electrode/electrolyte interfacial contacts, which can be formed during cell fabrication and worsened due to cycling. Constant current discharging processes at different rates and contact areas were simulated to correlate the capacity drop with the contact area loss. Furthermore, the model suggested how much pressures should be applied to recover the capacity drop due to contact area loss.
Surface Functionalization of Metal-Organic Framework Prior to TiO2 Tethering for Oxygen Reduction Catalysis in Alkaline Media
Authors: Grewal Simranjit , Macedo Angela , Lee Min Hwan
Published: February 2020

Oxygen reduction reaction (ORR) is one of the most studied reactions for clean energy devices such as fuel cells and metal-air batteries due to its intrinsically sluggish kinetics which often limits device performance. Non-precious transmission metal oxides (TMO) such as Fe3O4, MnOx and Co3O4[1] have been intensively probed as alternatives to platinum-based catalysts. To supplement low electronic conductivity of TMOs, they are often dispersed on a highly conductive carbon nanostructure with a large surface area, maximizing catalytically active sites per volume and mass.

We employ a hybrid structure where both cobalt and cerium nitrate salts with a ligand called [1,1’-Biphenyl]-4,4’-dicarboxylic acid create an MOF (MOF-Ce-Co) with extreme surface area and excellent electronic conductivity using the hydrothermal process and pyrolysis. While this structure is conductive, its conductivity can be improved with the functionalization of cerium particles. Specifically, Ce(IV) complexes have been reported to show superior rates of phosphonate ester bond cleavage compared to other metal oxides. The unprecedented activity of Ce(IV) has been attributed to the role of the Ce(IV) 4f orbitals that can mix with the orbitals of the P=O bond to form hybrid orbitals[2]. To functionalize cerium, phosphoric acid is used to bind a phosphate group onto cerium oxide. This gives rise to a penta-coordinate intermediate that is susceptible to a nucleophilic attack[2]. The treated MOF-Ce-Co is then hydrothermally reacted (at 160 ºC for 24 h) with the precursor P25, thus creating MOF-Ce-Co with TiO2 attached.

Results have indicated that phosphate groups not only absorb cerium nanoparticles, but TiO2 thus resulting in enhance performance in terms of current density, and onset/half-wave potential as seen in both CV and LSV data. FT-IR results indicate that an absorption of 1040 cm-1 (corresponding to a phosphate group) appeared once MOF-Ce-Co was treated with phosphoric acid. An X-ray analysis showed that both samples (MOF-Ce-Co and MOF-Ce-Co with TiO2) had cerium and cobalt particles, however, MOF-Ce-Co with TiO2 had an additional peak at 56º, indicating that presence of TiO2 (Anatase). Hence, the improved performance of the treated MOF is the result from functionalization.

This project was funded by NASA Advanced STEM Training and Research (ASTAR) Fellowship.

References:

[1] G. Wu and P. Zelenay, “Nanostructured nonprecious metal catalysts for oxygen reduction reaction.,” Acc. Chem. Res., vol. 46, no. 8, pp. 1878– 89, Aug. 2013.

[2] T. Islamoglu, A. Atilgan, S. Moon, G. Peterson, J. DeCoste, M. Hall, J. Hupp, and O. Farha, "Cerium(IV) vs Zirconium(IV) Based Metal-Organic Framwork for Detoxification of a Nerve Agent." Chemistry of Materials., vol. 29, no. 7, pp. 2672-2675, May 2017.

Figure 1
Hierarchical Carbon Nano Fibres for Flexible Zn-Air Batteries
Authors: Liu Xinhua , Ouyang Mengzheng , Wang Huizhi , Brandon Nigel P. , Georage Chandramohan , Wu Billy
Published: February 2020

Nanostructured functional materials, specifically carbon nanofibres/nanotubes, are attractive due to their chemical stability and electrochemical properties. Carbon based structures across different length scales have already been used in a range of energy applications including carbon papers for proton exchange membrane fuel cells, carbon nanofibers for supercapacitors and carbon nanotubes as conductive additives in lithium-ion batteries. The development of hierarchical, designed nanomaterials bridging length scales is required for next generation devices because each length scale of interest offers certain advantages, macro-scale fibres offering ease of fabrication and nano-scale tubes offering superior electrochemical performance. Functional carbon nanofibers with hierarchical architectures are essential components in advanced energy applications. Here, we present a simple approach to preparing highly engineered, hierarchical nanofibers and a simple heat treatment. This simple synthesis route has been successfully developed to prepare a 3D structure consisting of large backbone fibres decorated with hierarchical, small carbon nanotubes produced via in-situ growth during carbonisation. The carbon nanofiber with hierarchical structure can significantly enhance the nanoporous 3D carbon network by increasing the specific surface area and number of electron and ion pathways, resulting in a doubled power density when compared to the carbon nanofiber without hierarchical structure. When utilized as an air cathode in the solid-state zinc-air battery, the carbon nanofiber with hierarchical structure showed markedly better electrochemical performance, delivering a long cycle life while remaining highly flexible.
Study of SEI Components Enabling Calcium Metal Plating and Stripping
Authors: Forero-Saboya Juan , Yousef Ibraheem , Davoisne Carine , Dedryvère Rémi , Canepa Pieremanuele , Ponrouch Alexandre
Published: February 2020

Due to serious concerns about future availability and price increase of lithium minerals, several alternatives have been investigated to substitute lithium-ion batteries in high demand applications. Divalent-cation chemistries, such as calcium and magnesium, promise a high energy capacity relying on much more abundant elements (5th and 8th, respectively, in the earth crust) than lithium (25th). Until recently, the development of such battery concepts was focused on electrolytes that do not form passivation films (solid electrolyte interphases - SEI) on the metal surface [1]. These electrolytes, however, suffer from a low stability towards oxidation and thus, limit the output voltage of the assembled cells.

Previous works from our group demonstrated calcium plating and stripping in SEI-forming electrolytes at moderate temperatures [2]. Specifically, redox activity of calcium metal was observed in a Ca(BF4)2 electrolyte dissolved in a mixture of cyclic carbonates, while no activity was observed when TFSI was used as anion.

The current study focuses on understanding the chemical composition differences between the SEI layers formed in the two systems analysed. A systematic characterization of the SEI formed on the Ca metal anode in various electrolyte formulations will be presented and the most suitable SEI compounds in terms of divalent cation mobility will be discussed.

References

[1] J. Muldoon, C. B. Bucur and T. Gregory, Chem. Rev., 2014, 114, 11683–11720.

[2] A. Ponrouch, C. Frontera, F. Bardé and M. R. Palacín, Nat. Mater., 2016, 15, 169–172.
(Invited) Beneficial Effect of Fsi-Based Electrolytes on Capacitor Performance
Authors: Ishikawa Masashi , Uchida Satoshi , Hirota Naoya
Published: February 2020

A lithium ion capacitor (LIC) is an electric energy storage device that combines an electric double-layer capacitor (EDLC) with a lithium ion battery (LIB). Although LIC features an excellent power density like EDLC, the energy density of LIC is lower than that of LIB. Therefore, improvement of energy density is required for LIC. In the present study, to achieve high energy density of LIC, porous 3-dimensinal (3-D) current collector is applied to LIC electrodes. This 3-D current collector can increase the packing density of active material. It is, however, expected that diffusion of ionic carriers is limited when using conventional organic electrolytes because electrodes based on the 3-D current collector should be massive. As a result, LIC using the 3-D current collector may deliver limited power. Here bis(fluorosulfonyl)imide (FSI)-based ionic liquids (ILs) that have high carrier density would be useful as an electrolyte for LIC to maintain power. The purpose of this study is applying an FSI-based IL electrolyte to LICs with porous 3-D current collector.

We assembled a three-electrode cell. A positive electrode using aluminum 3-D current collector was composed of activated carbon, acetylene black (AB) and polyvinylidene di-fruoride (PVdF). A negative electrode using copper 3-D current collector was composed of hard carbon, AB and PVdF. A lithium foil was used as a counter electrode and reference electrode. We used LiFSI/EMImFSI as an IL electrolyte. The cell was charged and discharged for 3000 cycles at 1.0 C-rate in a voltage range of 2.0 – 3.8 V. We also evaluated rate performance of the LIC cells by rapid charging and discharging test up to 30 C-rate.

Potential profiles of positive and negative electrodes were observed during charge and discharge at the 2nd, 1000th and 3000th cycles. It turns out that the LIC cell containing the IL electrolyte can be charged and discharged reversibly as well as stably. Even though a test was long-term cycling such as 3000 cycles, the capacity has not significantly decreased. We compared rate performance among the IL electrolyte and two organic electrolytes. Although ILs have high viscosity, it is shown that the FSI-based IL electrolyte has high rate performance comparable to that of a LiPF6-based organic electrolyte. This may be ascribed to high carrier density of the IL. These results suggest that applying the IL electrolyte to a LIC electrode with the porous 3-D current collector is promising to keep or enhance energy and power capability.

We will also report the effect of FSI-based electrolytes including IL systems and solvent-based ones on the charge-dicharge performance of EDLCs.