bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ambient Pressure XPS Studies of Liquid Solid Interfaces in Batteries
Authors: Edström Kristina , Maibach Julia , Källquist Ida , Lindgren Fredrik , Hahlin Maria 
Published: February 2020

Liquid solid interfaces in batteries are not trivial to study in a realistic and detailed way. Often interfaces of cathodes or anodes in cycled batteries, are studied post mortem and at ultra-high vacuum to really determine the chemical composition in the outermost electrode/electrolyte layer. It is, therefore, a need to develop new characterisation methods which can allow for the study of dynamic reactions taking place at interfaces as a function of battery cycling. In this presentation, we will describe our attempts to develop electrochemical cells that can be used at ambient pressure (25 mbar). The cells are dependent on photoelectron spectrometers (PES) that have differential pumping systems and where the samples can be protected but still transferred without intermediate ultrahigh vacuum step of the load lock. These spectrometer exist now at synchrotron facilities but also as in house equipment. The challenge is how the electrochemical cell should be designed and how to study the liquid solid interfaces in detail and especially when the liquids are organic volatile solvents.
Our first results will be presented as three examples. The first example is a comparison of the solid electrolyte interphase (SEI) on a silicon surface measured at ultrahigh vacuum with one measured at ambient pressure. Questions such as: will the chemical composition of the SEI be considerably different at ambient pressure and will the resolution of the analysis be high enough to reveal any differences in the chemical composition? The second example is a study of the surface of a droplet of a lithium-ion battery electrolyte on a metallic lithium substrate characterised at 2 mbar and 0.2 mbar, respectively, and studied with ambient pressure PES. The study was performed on the beam-line Hippie at MAXIV laboratory. Our third result is the cycling of an electrode with an electrolytes within electrochemical cell in the Hippie spectrometer. The implication of all these three studies is that a step has been taken to more realistic studies of surface reactions in a LIB context. The experimental challenges are also detailed in the presentation.
Fabrication of Super Hydrophobic Gas Diffusion Layers
Authors: Thumbarathy Deepashree Sudhir , Das Prodip K 
Published: February 2020

Gas diffusion layer (GDL) plays a significant role in water management and heat removal within the polymer electrolyte fuel cells (PEFCs). When the GDL is flooded with liquid water, PEFC undergoes mass transport losses due to pore blockage by water which leads to decreased cell performance. For this purpose, the fabrication of selective wetting pattern by spray coating on the GDL surface is reported in this study. The present study will investigate the surface morphology of the GDL determined by its pore geometry and hydrophobicity which can control the water transport in PEFCs. Commercial GDLs were selected as a substrate. Two different monomers were used and their emulsions of required concentration were spray coated and polymerised to achieve the hydrophobic coatings. Regardless to monomer’s viscosity, super hydrophobic coatings on Commercial GDLs were obtained via spray coating with a contact angle of 1590 or higher, while the base surface’s contact angle was in the range of 1000.
The fabricated GDLs were further analysed by means of sliding angles and scanning electron microscopy. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the successful introduction of the functional groups in both the coatings. Pore size distribution and adhesion forces measurement were used to investigate the water droplet transport on the coated GDLs. In this presentation, the results of our study will be discussed with the aim of highlighting how these results will benefit the water management of next generation high-power PEFCs.
On the Relation between Ionic Transport Properties and Viscoelastic Response of Solid Polymer Electrolytes
Authors: Grazioli Davide , Panteghini Andrea , Simone Angelo 
Published: February 2020

The need for high energy density and micro-scaled power sources is pushing researchers and industries towards the development of three-dimensional architecture micro-batteries and structural batteries. In this perspective, solid polymer electrolytes (SPEs) represents an appealing alternative to conventional (liquid) electrolyte. Due to their intrinsic multifunctionality, SPEs can serve as the structural matrix of fiber-reinforced composites and as the electrolyte of a battery. In addition, the improved safety features, excellent flexibility and processability, allow to cast SPEs into complex three-dimensional geometries without leakage.
Experimental studies indicate that mechanical and electrochemical responses of SPEs are related. In particular, the segmental motion of the polymer molecules is crucial for both the viscoelastic properties and the ionic conductivity of the material. A limited polymer segmental motion generally results in a stiffer mechanical response and a reduced ionic conductivity, while the opposite applies when the polymer segmental motion is enhanced. This results in a trade-off between mechanical and electrical performance from a material design point of view [1] and a deformation-dependent ionic transport mechanism in the polymer during service [2].
In this work we present a coupled electrochemo-mechanical model for SPEs. The polymer is modeled as a solid through which the transport of multiple charged species takes place and is described in terms of molar concentration of ions, electric potential and displacement field. Since the molar concentration of ions in the SPE is notably non-uniform during battery service [3,4], the model explicitly accounts for concentration-dependent diffusion coefficients and viscoelastic properties. Results of a finite element method formulation are presented, and the impact of the viscoelastic mechanical behavior on the overall battery response is discussed.
References:
[1] Asp, L.E. and Greenhalgh, E.S., "Structural power composites", Composites Science and Technology, 101, pages 41-46 (2014).
[2] Kelly, T., Ghadi, B.M., Berg, S. and Ardebili, H., "In situ study of strain-dependent ion conductivity of stretchable polyethylene oxide electrolyte", Scientific Reports, 6, page 20128 (2016).
[3] Grazioli, D., Verners, O., Zadin, V., Brandell, D. and Simone A., "Electrochemical-mechanical modeling of solid polymer electrolytes: Impact of mechanical stresses on Li-ion battery performance", Electrochimica Acta, 296, pages 1122-1141 (2019).
[4] Grazioli, D., Zadin, V., Brandell, D. and Simone A., "Electrochemical-mechanical modeling of solid polymer electrolytes: Stress development and non-uniform electric current density in trench geometry microbatteries", Electrochimica Acta, 296, pages 1142-1162 (2019).
(Invited) Modeling the Defect Chemistry, Transport Properties, and Stability of Antiperovskite Materials
Authors: Ciucci Francesco 
Published: February 2020

Solid-state electrolytes with fast lithium conduction are the core of the all-solid-state Li battery technology. By substituting the organic electrolyte with a piece of non-flammable ceramic material, we can achieve better safety, higher specific capacity, and a higher energy density. To date, the major bottleneck for this technology is the slow Li diffusion in the solid-state electrolyte and the interfacial incompatibility between the electrolyte and electrodes. To resolve these issues, several families of fast ionic conductors have been developed. The understanding of Li diffusion in these materials is essential to the development of novel family fast ionic conductors. To this end, atomistic modeling provides us with a unique tool to obtain comprehensive information on the atom motion, which is difficult to access with experimental techniques. In this talk, we showcase our group’s atomistic simulations regarding a novel family of superionic conductors, Li-rich anti-perovskites (LiRAPs)
LiRAPs are a promising family of solid electrolytes, which exhibit ionic conductivities above 10-3 S cm-1 at room temperature, among the highest reported values to date. We first investigated the defect chemistry and the associated lithium transport in Li3OCl, a prototypical LiRAP, using DFT calculations and classical MD simulations [1]. We also studied the phase, interfacial, and voltage stability of these materials [2] with DFT, showing good agreement with experiments. Analogous simulations were also carried out for Na-rich anti-perovskites [3].
References:
[1] Z Lu, C Chen, ZM Baiyee, X Chen, C Niu, F Ciucci. Defect chemistry and lithium transport in Li3OCl anti-perovskite superionic conductors. Physical Chemistry Chemical Physics 17 (48), 32547-32555 (2015)
[2] Z Lu, F Ciucci. Anti-perovskite cathodes for lithium batteries. Journal of Material Chemistry A, 6, 5185-5192 (2018)
[3] TH Wan, Z Lu, F Ciucci. A first principle study of the phase stability, ion transport and substitution strategy for highly ionic conductive sodium antiperovskite as a solid electrolyte for sodium ion batteries. Journal of Power Sources, 390, 61-70 (2018)
New Electrode Materials for Sodium Ion Batteries
Authors: Munnangi Anji Reddy , Maria Joseph Helen , Fichtner Maximilian , Euchner Holger 
Published: February 2020

Sodium-ion batteries (SIBs) are evolving as a low-cost alternative to the state-of-the-art lithium-ion batteries (LIBs). Elementary properties of sodium, high abundance and low cost associated with sodium precursors made it a realistic alternative to lithium-ion chemistry [1, 2]. Research activities on SIBs are growing worldwide and still require a great deal of basic research. Currently, the research on SIBs is focused on the development of new cathode and anode materials or combinations with improved properties such as high energy density, sustainability, and safety.
Sodium insertion in hard carbon is strongly debated, and a full and consistent picture of the underlying mechanism is still missing. By combining in-situ Raman spectra obtained during sodium insertion in hard carbon with detailed ab initio studies, for the first time we provide a complete description of the Na insertion process in hard carbon [3]. On the cathode side, we propose weberite-type sodium metal fluorides (SMF), a new class of high voltage and high energy density materials which are so far unexplored as cathode materials for SIBs [4]. Weberite-type is highly favorable for sodium-containing transition metal fluorides, with a large variety of transition metal combinations (M, M’) adopting the corresponding Na2MM’F7 structure. A series of known and hypothetical compounds with weberite-type structure were computationally investigated to evaluate their potential as cathode materials for SIBs. Weberite-type SMFs show quasi-three-dimensional pathways for Na+ diffusion with surprisingly low activation barriers. The high energy density combined with low diffusion barriers for Na+ makes this type of compounds promising candidates for cathode materials in SIBs. We also present the synthesis and electrochemical properties of new sodium vanadium oxy phosphate (NaVOP), Na2+xV3P2O13 (0 ≤ x ≤ 2). NaVOP shows a reversible capacity of 150 mAh g-1 at an average voltage of 2.5 V vs. Na/Na+, with high cycling stability [5]. The post-structural analysis shows Na2+xV3P2O13 (0 ≤ x ≤ 2) is structurally stable over a wide range of sodium extraction and reinsertion demonstrating its potential as cathode material for SIBs.

References:

D. Slater, D. Kim, E. Lee, C. S. Johnson, Adv. Funct. Mater. 2013, 23, 947–958.

Yabuuchi, K. Kubota, M. Dahbi, S. Komaba, Chem. Rev. 2014, 114 (23), 11636–11682.

Anji Reddy, M. Helen, A. Groß, M. Fichtner, H. Euchner, ACS Energy Lett., 2018, 3, 2851–2857.

Euchner, O. Clemens, M. Anji Reddy, submitted.

Anji Reddy, H. Euchner, R. Witter, O. Clemens, J. Mater.
Chem. A, 2018,
6
, 6947–6958.
(Invited) Taking a Closer Look at SEI Chemistry
Authors: Xu Kang C. 
Published: February 2020

Interphases enables the electrodes to operate at potentials beyond what thermodynamic stability limits of non-aqueous electrolytes would allow. The most prominent example of interphases is perhaps solid-electrolyte-interphase (SEI) on graphitic anodes in Li-ion batteries, which ensures the reversibility of Li-ion intercalation chemistries. In typical electrolytes, chemical building blocks of SEI mainly come from solvents decomposition products, and, although we often acknowledge that many aspects of SEI remains unknown, we thought we at least have establish the following foundation beyond doubt: (1) semi-carbonates from the single-electron reduction of carbonate solvents constitutes the major portion of SEI; (2) the formation of SEI is irreversible; and (3) SEI is ionic conductor and electron insulator. However, when taking a closer look at the “olde SEI” using a series of new techniques, we found some of those principles might need to be re-written.
In this work, I will summarize the newest understanding of this “least understood” component in Li-ion battery that were achieved in my own group and my collaborators.
A Study of Practical Operating Challenges in Alkaline Electrolyte for Rechargeable Zinc-Air Batteries
Authors: Sun Wei , Zhang Mengyi , Winter Martin , Bieker Peter 
Published: February 2020

As one of the proposed post lithium-ion battery technologies, metal-air batteries have received revived interest recently. Among the different types of metal-air batteries, rechargeable zinc-air battery (RZAB) is a promising electrochemical energy storage device with the advantages of high theoretical energy density of 1086 Wh kg-1, high abundance, low toxicity and intrinsic safety.1 However, current RZAB still suffer from poor energy efficiency and cycle life, owing mainly to the zinc-anodes, electrolytes, and air-cathodes. To improve the low energy efficiency, many efforts have been made to promote both of the sluggish oxygen reduction/evolution reactions in the air-cathodes by engineering bifunctional catalyst materials with high reactivity. Although significant progress has been made in developing suitable catalyst materials for the air-cathode, many technical challenges still remain in electrolyte to achieve the long cycle life while maintaining high performance.
Aqueous electrolytes, predominantly alkaline electrolytes, have been adopted by the RZAB system since its birth. Potassium hydrogen (KOH) is the most commonly used alkaline electrolyte because of its high ionic conductivity, high activity for both the zinc and air electrodes as well as good low temperature performance.2 Despite its desirable properties, the usage of KOH in RZAB raises several technical problems: i) zinc dendrite formation, shape change, surface passivation from complicated reaction between zinc and OH- as well as the dissolution and migration of Zn(OH)4
2-; ii) corrosion of the carbon-based air cathode in concentrated alkaline electrolyte; iii) formation of insoluble K2CO3 arising from the reaction of aerial CO2 with KOH; iv) reduced cell shelf due to the high corrosive ability of concentrated alkaline electrolyte to the stainless steel used in the experimental cell component.
In this work, specific attention is given to the obstacles caused by the alkaline electrolytes with the focus on the fundamental understanding of zinc-anode reaction mechanisms, carbonization of electrolyte as well as the precipitation of carbonates on the air cathode. Furthermore, the effects of the practical operating conditions on battery performance and durability are discussed, including the experimental cell configuration for RZAB as well as the contaminants commonly encountered in ambient air (e.g. carbon dioxide). The approaches to overcome the challenges are also presented and analyzed for facilitating further research and development of the electrolyte for RZAB.

Reference

Li, Y.; Dai, H., Recent advances in zinc-air batteries. Chemical Society reviews
2014,
43 (15), 5257-75.

R. Mainar, A.; Leonet, O.; Bengoechea, M.; Boyano, I.; de Meatza, I.; Kvasha, A.; Guerfi, A.; Alberto Blázquez, J., Alkaline aqueous electrolytes for secondary zinc-air batteries: an overview. International Journal of Energy Research
2016,
40 (8), 1032-1049.
On the Electrochemical Intercalation of Ca2+ and Mg2+ Ions in Layered TiS2: A Fundamental Study in Alkyl Carbonate Based Electrolytes
Authors: Verrelli Roberta , Tchitchekova Deyana S. , Ponrouch Alexandre , Black Ashley , Arroyo-de Dompablo M. Elena , Frontera Carlos , Palacin M. Rosa 
Published: February 2020

Batteries based on naturally abundant, light metal anodes (such as Ca and Mg) and multivalent ion host cathodes can potentially achieve very high energy densities at relatively low cost and environmental impact, thus representing a compelling alternative to currently available Li-ion systems.
While reversible Ca metal plating and stripping in conventional alkyl carbonate based electrolytes has been accomplished [1,2], unraveling cathode materials with fast and reversible ion mobility at high operating voltages remains a major open challenge, mainly hampered by the slow diffusion kinetics in the solid state of multivalent ions. Thus, besides the exploration of new materials, revisiting traditional layered intercalation hosts appears as a very useful tool to gain further insight into the fundamentals of divalent ion intercalation.
In this context, a thorough study of the electrochemical intercalation of Ca2+ in layered TiS2, in alkyl carbonate based electrolytes, is herein presented [3]. Fundamental insights on the insertion process are acquired through X-ray diffraction. Ca2+ insertion is unambiguously proved by using both X-ray diffraction and differential absorption X-ray tomography at the Ca L2 edge and the reversibility of the process is demonstrated at moderate temperature.
Different phases can be formed upon reduction of pristine TiS2, whose amount and composition dependon the experimental conditions employed. A comparative study with Mg2+ containing electrolytes and other conventional intercalation hosts, such as V2O5, was also carried out. Careful examination of results highlights the potential relevance of side reactions in these system and the need to use several complementary characterization techniques to unambiguously assess divalent ion intercalation.
[1]A. Ponrouch, C. Frontera, F. Bardé and M. R. Palacín, Nat. Mater. (2016), 15, 169.
[2] A. Ponrouch, M. R. Palacín, Curr. Opin. Electrochem. (2018), 1.
[3] Tchitchekova D.S., Ponrouch A., Verrelli R., Broux T., Frontera C., Sorrentino A., Biskup N., Arroyo-de Dompablo M.E., Bardé F., Palacín M.R., Chem. Mat. (2018), 30, 847.
MoS2/Carbon Cloth As Free-Standing and Flexible Anode for Sodium-Ion Hybrid Capacitors
Authors: Lin Wei-Hsiang , Chen Han-Yi 
Published: February 2020

Sodium-ion hybrid capacitors (NICs) combine the advantages of both battery and supercapacitor, exhibiting high energy and power density. Nevertheless, the sluggish kinetics of battery-type anodes limits its synergy effect with capacitor-type cathodes, which impedes both rate performance and cycling stability. Therefore, it is necessary to develop suitable anode materials for NICs, in order to enlarge the working voltage and long-term stability.
Molybdenum disulfide (MoS­2) is a material with layer structure and can easily store lithium and sodium ions, showing promising energy storage characterization. However, the low electrical conductivity and particles aggregation problems confines its capacity performance. In this work, we grow crescent-like MoS­2 on the carbon cloth to prepare a free-standing and flexible anode without binder. MoS­2 is mainly in charge of ion intercalation and deintercalation; on the other hand, carbon cloth is utilized as a conductive substrate for MoS­2 growth.
The Raman shift peaks of MoS­2 /carbon cloth are at about 375 cm-1 and 402 cm-1, corresponding to MoS­2 in-plane and out-of-plane vibration modes. Energy dispersive spectroscopy mapping shows that MoS­2 is uniformly distribute on the carbon substrate. These results demonstrate that MoS­2 successfully grew on the carbon cloth. Furthermore, electrochemical performances of MoS­2 /carbon cloth electrodes were measured in the potential range from 0.01 V to 3 V vs. Na/Na+. After combining MoS­2 with carbon cloth, the discharging capacity enhanced from 110 mA h g-1 to about 250 mA h g-1 at 50 mA g-1. These results indicate that MoS­2/carbon cloth hybrid material is a potential anode for NICs.

Keywords: Na-ion hybrid capacitors, MoS­2, Free-standing and flexible anode

Figure 1
High Power Energy Storage: New Materials for Large Format Supercapacitors
Authors: Wheeler-Jones Evangeline Chloe , Loveridge Melanie J , Roberts Alexander John 
Published: February 2020

Electrochemical double layer capacitors are well known for their high power output. However, pseudocapacitors have recently demonstrated the ability to compete here, with hybrid devices being a compromise between high power and high energy, by way of combined battery and supercapacitor technologies. Metal oxides have shown promising performance within battery and supercapacitor operation. However, cost and low conductivity have limited the performance of many of these materials and has led to the need for doping the material and refining particle shapes and sizes.1 Molybdenum dioxide is a promising material, having many properties required for pseudocapacitance, including its electrical conductivity (atypical for a metal oxide.)2,3 Further to this it has a theoretical specific capacity of 838 mAhg-1 when undergoing a four electron redox reaction. The various niobium oxides have multiple oxidation states, chemical stability and a high potential window making them suitable for energy storage.4 As niobium pentoxide has a theoretical capacity of 200 mAhg-1, which is higher than lithium titanate, (a common anode5), these materials have been tested in batteries and supercapacitors. Yet there remains considerable room for investigation surrounding mixed and doped versions of these materials.
Facile one-pot hydrothermal synthesis was used to make nanostructured pseudocapacitive materials. Molybdenum dioxides and niobium oxides were systematically synthesised with varied reaction conditions to gain shape and size control. Molybdenum dioxide nanoparticles were synthesised with the addition of a shape director to form spherical secondary particles. Upon doping the molybdenum dioxide with niobium, crystalline nanoparticles were formed with an average diameter of ~150 nm. Undoped niobium oxides form ‘flower-like’ particles, with the addition of a molybdenum precursor the reaction yields molybdenum dioxide/niobium oxide composite where molybdenum dioxide nanoparticles decorate the niobium oxide particles.
All materials were manufactured into electrodes using conventional processing methods and activated carbon electrodes were made for asymmetric devices. The materials showed varying electrochemical properties directly influenced by characteristics gained through the synthesis conditions. Electrochemical testing was carried out on these materials vs. Li’Li+ in half-cells and in asymmetric supercapacitor cells to assess their suitability for hybrid devices.

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X. Li et al., J. Power Sources, 237, 80–83 (2013) http://dx.doi.org/10.1016/j.jpowsour.2013.03.020.

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E. Lim et al., ACS Nano, 8, 8968–8978 (2014).

Figure 1