bluuebunny/crossref_metadata_2025 huggingface dataset:
Bottom-up Design of Organic Selenide Interfaces for Sensitive Electrocatalytic Detection of Peroxynitrite: A Fundamental Investigation and Application
Authors: Kalil Haitham , Curtis William , Menches Victoria , Azeroual Sami , Fouad Farid , Bayachou Mekki
Published: November 2022

Peroxynitrite (PON) is a potent oxidative stress species that has been linked with both oxidation and nitration reactions in biological systems. It emerged as a major cytotoxic agent that is implicated in a host of pathophysiological conditions. Reports emphasized the deleterious physiological reactivity of peroxynitrite with different cellular targets including DNA, proteins, and lipids in cell membranes. This oxidant has also been linked to cytoprotective roles under certain conditions. The balance between the deleterious reactivity and its potential cytoprotective roles of peroxynitrite depends on the dynamic concentration of this species. However, accurate determination of peroxynitrite concentration is inherently difficult particularly in biological systems. Various methods for peroxynitrite determination have been reported including indirect spectroscopic assays and, recently, direct electrochemical methods. While the development of electrochemical sensors for PON is currently a very active field, viable electrochemical probes for PON detection and quantification are still relatively illusive.

In this work, we prepared and characterized a series of functional thin film materials based on organic diphenyl selenides on graphite electrodes and used these interfaces to compare and contrast their performance in terms of electrochemical determination of peroxynitrite.

We will describe the preparation and grafting of the catalytic material based on the electrodeposition of various organic aminodiphenyl selenides on graphite electrodes. Several physicochemical methods including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the resulting modified interfaces. We will describe the performance of resulting selenide thin films as peroxynitrite sensing interfaces using voltammetry and amperometry. The grafted thin film materials show a significant enhancement in peroxynitrite oxidative current compared to controls under the same conditions. For all selenides tested, we show that the enhancement in peroxynitrite signal is the result of an electrocatalytic mechanism where the grafted aniline selenide-based material at the oxidized state mediates the electrocatalytic oxidation of peroxynitrite. We will compare and contrast the performance of the various selenide systems and explore if the modulation of the electronic properties of the selenium catalytic center results in proportional changes in PON catalytic efficiency.

Figure 1
Electrochemical Catalysis Generated By an External Electric Field in Conjunction with a Low Density-of-States Conductor
Authors: Boruta Nicholas , Alamgir Faisal M.
Published: November 2022

In electrochemistry the reaction rate depends strongly on the voltage difference applied between the two electrodes. A voltage increase at the electrodes will generate a larger electric field in the electric double layer (EDL), which increases the reaction rate, but this will also cause additional power to be dissipated. We show both theoretically and experimentally that one can increase the electrochemical reaction rate, at no additional cost in power, by utilizing an external electric field in the proximity of a material catalyst. This is not surprising since, although the exact mechanism for catalysis due to a material compound can be quite intricate, the basic underlying physical processes for catalysis can often be shown to be due to the molecular electric field at a specific catalyst surface site. Here we generalize this observation and show how the application of a ‘simple external’ electrostatic field in conjunction with a low density-of-states conductor such as graphene can be used to intensify the already large electric field in the EDL layer - thus accelerating the reaction rate without additional power dissipation. We focus on water electrolysis (more specifically, the hydrogen evolution reaction - HER) in our electrochemical reaction study. Based on our observed experimental results as well as our theoretical analysis we show how an electrode incorporating trapped charge at the interface between two dielectrics will generate a large electrostatic field which, in conjunction with the quantum capacitance of a low density-of-states conductor, allows penetration of this field into the electric double layer (EDL), thereby adding to the original EDL field and thus, functioning as a reaction rate accelerant or a catalyst. Our experiment shows a 100% increase in the hydrogen generation rate for the HER reaction when employing our external electrostatic ‘catalyst’ technique. Since this method depends primarily on the enhancement of the EDL electric field for the reaction rate increase, it can be universally applied to all electrochemical reactions without requiring a detailed molecular level understanding of the reaction of interest.
Unveiling the Effect of Flue Gas Contaminants on Electrochemical Reduction of CO2 to Methyl Formate in Dual Methanol/Water Electrolysis System
Authors: Gautam Manu , Hofsommer Dillon , Theaker Nolan , Grapperhaus Craig , Spurgeon Joshua M.
Published: November 2022

Exploiting renewable energy sources to drive CO2 reduction electrochemically into value-added products has gained tremendous attention towards reducing the greenhouse effect. Upstream processes for capturing and purifying the CO2 raise the overall cost of the electrolysis system. Direct reduction of flue gas into value-added C2+ products has attained much consideration in recent years. However, the sensitivity of the cathode catalyst performance in the presence of flue gas contaminants, particularly O2, and strong competition from the hydrogen evolution reaction in aqueous electrolyte are major challenges for such an approach. Herein, the influence of flue gas contaminants on electrochemical reduction of CO2 in acidic nonaqueous methanol to a methyl formate product has been investigated on a Pb-catalyzed electrode in conjunction with aqueous anolyte for the promotion of a sustainable water oxidation half-reaction. The presence of 4% O2, 0.05% SO2, and 0.05% NO is shown to have minimal effect on the total faradaic efficiency of CO2 reduction products. CO2 concentration-dependent measurements reveal declining CO2 reduction faradaic efficiencies corresponding to the decrease in partial pressure, which is attributed to CO2 mass transfer limitations to the electrode surface. XPS analysis displays the relative stability of the Pb working electrode before and after the electrochemical operation during exposure to flue gas components, which further highlights the promising tolerance of this system for direct flue gas conversion.

Figure 1
Photopattern-Directed Electrodeposition of Microstructured Copper for Antibacterial Surface Coatings
Authors: Sconyers David J. , Longo Cameron M. , Maurer Joshua A.
Published: November 2022

The development of electrodeposited surfaces with antiviral or antibacterial properties is a critical need in light of the realities of current and future pandemics. Increased use of chemical disinfectants represents a growing environmental problem, and in many cases threatens the surface finish of decontaminated products. To engineer new solutions to this problem, we can mimic biological systems that exhibit self-cleaning or bactericidal properties. In nature, surface morphology at the micro- and nanoscale are known to dramatically affect the adhesion of microorganisms and viral particles. These kinds of defined patterns and textures may be realized artificially through directed electrodeposition of transition metals from aqueous solution onto material surfaces of interest. In this work, we demonstrate the generation of such surfaces, enabled by the coating of self-assembled monolayers (SAMs) of alkoxysilanes and alkylphosphonates onto mild steel. Photo-induced monolayer patterning (PIMP) has been employed to selectively generate defect sites in these molecular photomasks, characterized by contact angle (CA) measurements, Fourier-transform infrared spectroscopy (FTIR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). The electrolytic deposition of copper from aqueous solution onto the exposed steel in our photopatterned systems has been shown to result in variable surface microstructure. In addition, we will discuss biological assays to determine bacterial viability on the finished steel/copper surface.
Enzymatic Biofuel Cells Embedded Polymer-Based Soft Actuators
Authors: Ortega-Santos Amaia Beatriz , Qiu Yaxin , Martinez Jose Gabriel , Jager Edwin W.H.
Published: November 2022

Enzymatic biofuel cells are presented as an untethered alternative energy source that could power small implantable or wearable medical devices. However, most of these catalytic processes do not provide with enough energy to power common small electronic-mechanical devices. On the other hand, conducting polymer-based actuators are of great interest for their biocompatibility, flexibility, processability, possibility to be miniaturized and low power consumption. So far, these artificial muscles have been driven by external power sources that prevent them for being completely autonomous. There is a need for a novel power source to elaborate actuators that could use physiological processes as a driving force. These soft actuators’ low power consumption matches the electrical power generated by the biocatalysis of some enzymes, such as glucose oxidase and laccase in presence of glucose and oxygen in aqueous media. Here, we present the latest results in the development of polypyrrole-based soft actuators powered by enzymatic biofuel cells. The actuator consists of a tri-layer conductive substrate on which the polypyrrole is electrodeposited in both sides. The polypyrrole layers act as the active part, expanding and contracting upon a redox reaction, resulting in a bending movement. Tetrathiofulvlene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) electron transfer mediators are cast on the surface of the polypyrrole to help the electron transmission. The glucose oxidase and laccase enzymes are immobilized in the modified-conducting polymer surface, integrating the electrode to the actuator. The bio-catalysis of enzymes in presence of glucose and oxygen in aqueous solution provides the actuator with the electrons needed for the redox reaction, converting the chemical energy into mechanical energy, i.e., movement. The glucose-self-powered soft actuator may contribute to the development of more complex implantable, ingestible, or wearable biomedical devices such as cardio-stimulators, insulin pumps, or muscle implants.
The Construction and Validation of Rotating Electrodes in Molten Salts for the Measurement of Hydrodynamic Properties and Corrosion
Authors: Fuller Ranon G , Shum Rankin , Calabuig Simon , Rappleye Devin
Published: November 2022

Among electrochemical techniques, rotating electrodes are particularly useful for molten salt research due to their ability to precisely control the rate of mass transfer via the rotational rate of the electrode. Rotating electrodes create well-developed flow patterns with established mathematical relations for certain geometries. From these relations, it is possible to measure viscosities, diffusion coefficients, and other properties of molten salts relevant to nuclear material processing and molten salt reactors (MSR). Rotating electrodes have the potential to simulate the hydrodynamic conditions in a molten salt reactor and provide in situ feedback during corrosion testing. Additionally, rotating electrodes require significantly less material for corrosion testing than flow loops, offering a low-cost means to screen material and salt compositions for more expensive and larger flow loop experiments. Although rotating electrodes have been used extensively in aqueous solutions, there have been very few attempts to apply them to molten salts. The high efficiency electrochemical test (HEET) facility at Brigham Young University (BYU) has been designed and constructed specifically for rotating electrode tests in molten salts. The constructed cells will be presented along with initial test data to benchmark and validate the hydrodynamic relations in molten salts by comparing them to aqueous hydrodynamic relations for similar rotating electrode geometries.
Effects of Thermal Cycling Rate on the Glass Transition Behavior of Choline Chloride and Ethylene Glycol Deep Eutectic Solvent Mixtures
Authors: Glynn Kaylie , Sangoro Joshua
Published: November 2022

Deep eutectic solvents (DESs) are a class of mixtures with the potential to serve as designer materials, and substitute for conventional organic solvents used in a wide variety of applications. The eutectic behavior of these mixtures has been explored in some depth, but the characteristic tendency of these materials is to behave contradictory to ideal, anticipated behavior. Therefore, experimental analyses are paramount to understanding the molecular dynamics of these materials. In this work, we have assessed a series of DESs using incremental compositions of Choline chloride (ChCl) and Ethylene glycol (EG). We have explored the rate dependence of glass phase transitions in these ChCl:EG mixtures using differential scanning calorimetry by quantifying the impacts of thermodynamic kinetics. The supporting evidence demonstrates that thermal cycling rate significantly affects glass transition temperatures, suggesting the importance of defining rate-independent transition temperatures for these mixtures.
The Effects of Ionic Liquid Addition on the Heat of Polymerization of Additive Manufacturing Resins
Authors: Dobyns Breanna M , Duranty Edward , Reichert W. Matthew
Published: November 2022

Ionic liquids can be utilized in stereolithography (SLA) additive manufacturing resins to adjust multiple parameters of the resulting polymer, such as chemical stability, temperature stability, and other key physical properties. While studies into these properties are ongoing, little is known about the effects the presence of these ILs has on the polymerization process. This study intends to use a new technique incorporating acoustic levitation, FLIR thermography, and differential scanning calorimetry (DSC) to provide insight into heat of polymerization of the resins utilizing an approach previously developed in the Duranty laboratory. This technique allows a small amount of liquid to levitate in standing sound waves generated by transducers at the top and bottom of a 3D printed scaffolding. This novel approach maximizes the probability of heat transfer via convection (through the air/surrounding medium) while preventing heat transfer via conduction (through direct contact) that is normally observed in container methods, allowing for direct thermal imaging of the captured droplets. Two 405 nm lasers, mounted at the top and bottom of the apparatus, are utilized to mimic the lasers of SLA 3D printing which initiate the polymerization process. This apparatus allows for the direct observation of the temperature changes during the polymerization process.

A variety of ionic liquids were used in this investigation in order to study to effects of structure changes and ion effects. The study observed the effects of alkyl chain length, functional groups on the alkyl chain, anion effects, aromatic vs. non-aromatic, and potential co-polymer ionic liquids. Each ionic liquid was added to the commercial Clear V4 resin from Formlabs in the amount of 10 to 50 wt% ionic liquid. Once the mixtures were homogenous, 5 µL of each IL/resin mixture was suspended in the acoustic field. Thermographic data was collected before, during, and after the polymerization process which was initiated by exposure to 405 nm lasers. The heats of polymerization for each sample were calculated using heat capacity data collected via DSC along with the change in temperature of the droplet observed by FLIR thermographic imaging of the suspended droplet during polymerization. Thermal degradation temperatures of the resulting polymer matrices were determined via thermal gravimetric analysis (TGA). The combination of this data revealed that the addition of some of the ionic liquids targeted in this study reduced the heat of polymerization, while others increased it. Therefore, the cation and anion structures greatly impact the heat of polymerization.

Figure 1
(Invited) Understanding Transport Properties of Ionic Liquids By Targeted Modifications of Ion Structures
Authors: Welton Tom , Philippi Frederik , Koutsoukos Spyridon , Rauber Daniel , Kay Christopher , Hunt Patricia
Published: November 2022

Ionic liquids have been of great interest throughout this century and continue to find new applications in both academia and industry. This is largely due to their great versatility, with millions of potential combinations of cations and anions, which has led to them being described as 'designer solvents'. However, this leads to its own problems when it comes to choosing the optimum ionic liquid for any given application. To fully exploit this versatility, it is imperative to understand how the properties of ionic liquids arise from their constituent ions.

To derive meaningful structure-property relationships for ionic liquids is a complex task. It can be particularly difficult to isolate the cause of any property change arising from even simple modifications of ions. For example, changing the length of the alkyl chain of a cation in an ionic liquid also changes the volume and mass of the ion, all of which can affect a property such as ion mobility and consequent properties such as the viscosity and conductivity of the ionic liquid. A ‘targeted modification’ is a deliberate change in the structure of an ionic liquid ion that is designed to minimise the introduction of such confounding factors. The change must isolate what is of interest, so that we can study only one concept at a time. Once these structure-property relationships have been clearly defined, it will be possible to use these as design elements for new ionic liquids.

As well as experimental observations, it is possible to apply the targeted modification approach to a computer simulation. This provides both insight into experimental observations and predictions of potential targeted modifications before complex synthesis is attempted. Together, theory and experiment will enable the concept of ionic liquids as designer solvents to be realised.

In this presentation we apply the targeted modifications approach to the transport properties of ionic liquids.
Low Temperature Behavior of Alloy Anodes for Lithium-Ion Batteries
Authors: Cavallaro Kelsey Anne , Sandoval Stephanie Elizabeth , Thenuwara Akila , McDowell Matthew T
Published: November 2022

Lithium-ion batteries are ubiquitous in most energy storage applications, but they fail completely below about -20 ºC, which hinders their use in low-temperature applications, like electric aviation and space exploration. Materials that alloy with lithium offer high specific capacities and have been researched thoroughly at room temperature, but their low temperature behavior is not well understood, despite indications that they may exhibit superior performance. In this work, we characterize the electrochemical and structural changes of antimony, tin, and silicon anodes at temperatures down to -40 ºC using a tailored ether electrolyte. Antimony anodes exhibit reversible cycling at -40 ºC, with a first cycle specific capacity of 450 mAh g-1, and tin and silicon can be cycled at -20 ºC with first cycle specific capacities far exceeding that of graphite. In addition, three-electrode coin-cell experiments reveal strong influences of the lithium metal counter electrode on the overall galvanostatic voltage profiles; these influences become dominant at low temperature and obscure the inherent behavior of the alloy anodes. This finding highlights the importance of using an appropriate reference electrode for low-temperature experiments, especially for sensitive experiments such as the galvanostatic intermittent titration technique (GITT). GITT experiments revealed the contributions of kinetic processes and thermodynamic hysteresis as a function of temperature in these materials, and they showed that the different materials feature different kinetic and hysteretic behavior at low temperature. The low temperature electrochemical behavior of silicon is seemingly more dependent on structural changes during the lithiation/delithiation transformations, while tin and antimony are more strongly impacted by kinetic effects at low temperatures. Finally, X-ray diffraction experiments on antimony anodes reveal difference in the average crystallite size and crystallite evolution at low temperature during cycling. Overall, these results are an important for understanding the fundamental behavior of alloy materials at low temperature and are an important step for the engineering of high-energy, low-temperature lithium-ion batteries.
(Invited) Mechanically Extreme Batteries: From Flexible to Structural
Authors: Yang Yuan
Published: November 2022

Batteries with extreme mechanical properties are attractive for unique applications. On the soft side, flexible and stretchable batteries are attractive for wide applications, such as health care and flexible electronics. It is challenging to realize high flexibility/stretchability and high energy density simultaneously. In this talk, I will talk about feasible and scalable strategies to fabricate flexible lithium-ion batteries, which can concurrently have high energy density and high mechanical flexibility, including bendability, foldability, twistability and stretchability. Inspired by the structure of animal spine, the vertebrae-like hard segments with multiple layers of conventional anode/separator/cathode stack to offer energy storage are interconnected by the soft components as marrow with the monolayer stack to provide flexibility.

On the other hand, mechanically strong batteries are also important as they may replace structural components in vehicles and aircrafts for lightweighting. I will discuss a scalable and feasible tree-root-like lamination at the electrode/separator interface, which effectively transfers load between different layers of battery components and thus dramatically enhances the flexural modulus of pouch cells from 0.28 to 3.1 GPa. A graphite/LiNi0.5Mn0.3Co0.2O2 full cell with such interfacial lamination delivers a steady discharge capacity of 148.6 mAh g−1 at C/2 and 95.5% retention after 500 cycles. A prototype of “electric wings” is also demonstrated, which allows an aircraft model to fly steadily.
(Invited) Textile Composite Electrodes for Wearable Batteries and Beyond
Authors: Zheng Zijian
Published: November 2022

Abstract

Wearable energy storage devices are indispensable corner stones for future wearable electronics. Current energy storage technologies are based on materials and devices that are rigid, bulky, and heavy, making them difficult to wear. On the other hand, fibers are flexible and lightweight materials that can be assembled into different textiles and have been worn by human beings thousands of years. Different from conventional two-dimensional thin films and foils, the three-dimensional fibre and textile structures not only provide superior wearing ability, but also much larger surface areas. This talk will introduce how our research group makes use of the attributes of fibres for high-performance wearable energy storage devices. We will demonstrate the strategies and discuss the perspectives to modify fibers and textiles for making wearable capacitators and batteries with excellent mechanical durability, electrochemical stability, and high energy/power density. We will also show that the fibrous materials can significantly enhance the stability and energy density of battery for wearable applications and others such as Na battery.

References

[1] Q. Huang, D. Wang, Z. J. Zheng*, Adv. Energy Mater. 2016, 6, 1600783.

[2] Y. Gao, C. Xie, Z. J. Zheng*, Adv. Energy Mater. 2020, 2002838

[3] L. Liu, Y. Yu, C. Yan, K. Li, Z. J. Zheng*, Nat. Commun. 2015, 6, 7260.

[4] Y. Yu, C. Yan, Z. J. Zheng*, Adv. Mater. 2014, 26, 55085516.

[5] Y. Yang, Q. Huang, L. Niu, D. Wang, C. Yan, Y. She, Z. J. Zheng*, Adv. Mater. 2017, 160667.

[6] J. Chang, Z.J.Zheng* et al., Nat. Commun. 2018, 2018, 9, 4480.

[7] J. Chang, Q. Huang, and Z. J. Zheng*, Joule 2020, 4, 7, 1346

[8] J. Chang, Q. Huang, Y. Gao, Z. J. Zheng*, Adv. Mater. 2021, 202004419.

[9] Y. Gao, H. Hu, J. Chang, Q. Huang, Q. Zhuang, P. Li, Z. J. Zheng*, Adv. Energy Mater. 2021, 2101809.

[10] L. Wang, J. Shang, Q. Huang, H. Hu, Y. Zhang, C. Xie, Y. Luo, Y. Gao, H. Wang, Z. J. Zheng*, Adv. Mater. 2021, 2102802.
Electrolyte Additive Enabled Low Temperature Lithium Metal Batteries
Authors: Zhang Yiwen , Li Weiyang
Published: November 2022

One of the key challenges in the development of energy storage devices is the ability to operate efficiently under extremely cold environments (i.e. below -20 °C), especially for batteries in temperature-sensitive applications such as portable electronic devices, transportation, and stationary energy storage. As reported, at low temperature, the increased internal resistance and sluggish ion diffusion in batteries lead to declined charge-delivering capability, which deteriorates cell performance and eventually terminates the power output. Although lithium (Li) metal battery (LMB) with ether electrolyte is considered promising in overcoming these issues due to the low viscosity of ether solvent and its distinctive electrode structure, the low-temperature performance of LMBs remains unsatisfactory. A series of problems are observed upon the anode-electrolyte interphase, including aggravated side reactions, abnormal Li deposition, and dramatically increased solid-electrolyte interphase (SEI) resistance. Thus, building a stable SEI layer on the Li metal anode is critical for the development of low-temperature LMBs.

Here, we demonstrate a dioxolane (DOL)-based electrolyte with dimethyl sulfoxide (DMSO) as the low-temperature additive, which helps to construct a robust SEI layer that possesses uniform structure and good composition consistency even under extremely cold condition. In this electrolyte, DOL works as the primary electrolyte component that defines the basic electrochemical properties, while DMSO further tunes the SEI composition to boost the low-temperature performance. To elucidate the modified microstructure and chemical composition of the SEI film, cryogenic transmission electron microscopy, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy are conducted to make a comprehensive investigation. Moreover, a series of electrochemical tests are conducted under extremely cold environments, and results demonstrate that the adjusted SEI is resilient to the stripping and plating cycles of Li metal at temperatures as low as -80 °C. Full cells with lithium iron phosphate as the cathode material are assembled and good electrochemical performance is achieved at -40 °C at 0.2 C. The solvation structure of DMSO added electrolyte is also investigated to fundamentally understand how it affects the SEI formation. Our work establishes fundamental insights into the low-temperature electrolyte additives and paves the road to the further applications of LMBs in harsh environments.
Correlating Computation and Structural Analysis for LiFePO4 through Operando Characterization of Lithium-Ion Pouch-Cell Batteries
Authors: Long Jeffrey W. , DeBlock Ryan H. , Carter Rachel Elizabeth , Chervin Christopher N. , Love Corey T. , Johannes Michelle D.
Published: November 2022

X-ray absorption spectroscopy (XAS) is a powerful technique for exploring the electronic and structural characteristics of battery materials. Historically, XAS measurements require synchrotron-based photon sources to achieve necessary sensitivity and energy control, but with breakthroughs in X-ray optics, laboratory-based XAS systems are now available on the commercial market. The Chemistry Division at the Naval Research Laboratory recently acquired an easyXAFS™ system, a laboratory-scale spectrometer that is capable of collecting XANES (X-ray Absorption Near-Edge Spectroscopy) and EXAFS (Extended X-ray Absorption Fine Structure) measurements in the 5–18 keV energy window. This energy range covers K-edge absorptions for the first-row transition metals that are of primary interest for electrochemical energy storage. In order to demonstrate the utility of such a laboratory-based XAS, we perform operando measurements on pouch-cell batteries containing the common lithium-ion battery cathode, LiFePO4 (LFP; lithium iron phosphate), tracking Fe oxidation state and bonding environment as a function of state-of-charge. X-ray absorption spectra collected with the easyXAFS™ compare favorably to those from prior investigations of LFP cells analyzed at synchrotron sources [1]. In parallel with XAS measurements, we perform DFT (Density Functional Theory) computation of the LFP structure. Calculations of LFP show that hole-polaron formation during charging alters the local environment around the Fe ion, decreasing the Fe–O bond length. Bond contraction increases with the addition of the Hubbard "U", which also increases the valence difference (formally 2+/3+). We further refine the computational model for the LFP system by tuning the DFT input parameter “U” to correlate with experimental XAS data.

[1] C. T. Love, A. Korovina, C. J. Partridge, K. E. Swider-Lyons, M. E. Twigg, and D. E. Ramaker, J. Electrochem. Soc. 160 (2013) A3153.
Quantitative Characterisation of the Layered Structure within Lithium-Ion Batteries Using Ultrasonic Resonance
Authors: Huang Ming , Kirkaldy Niall , Zhao Yan , Patel Yatish , Cegla Frederic , Lan Bo
Published: November 2022

Characterising the internal states of lithium-ion batteries (LIBs) is vital for ensuring the performance, durability, and safety of the batteries, and it represents one of the most demanding and challenging aspects of rapidly-growing battery research. This work reports an exciting ultrasonic methodology for quantitatively characterising the internal layered structure of LIBs using ultrasonic resonance. This work first employs simple, conventional ultrasound equipment to experimentally acquire resonant signals from batteries. Then it establishes a new theoretical model from the ground up, to explain the physical principles of how resonance forms from layer reflections, and how to retrieve various crucial information about battery inner structures from the resonant signals. Finally, to showcase the capabilities of the new methodology, this work demonstrates that the technique is very successful in recovering the number of repetitive layers, the average thicknesses of anode and cathode active material coating layers, a spatially resolved image of internal layers in the depth direction, and the state of charge (SOC) with layer-to-layer resolutions. This new methodology's quantitative layer characterisation capability considerably improves the existing ultrasonic characterisation techniques. For example, the layer-resolved characterisation capacities, especially on the in-operando SOC monitoring, have not been achieved by other techniques yet. Also notable is that it maintains the same low-cost, in-operando operation as conventional ultrasonic or electrical signal-based methods. These qualities could make the reported technique a powerful tool for battery inner structure characterisation and management, enabling better quality control during production and quantitative monitoring of the states of health and charge during operation.
Bragg Coherent Diffraction Imaging Studies of Pt Nanograins Under Electrochemical Control Using Pipette Cells
Authors: Sheyfer Dina , Highland Matthew , Hruszkewycz Stephan , You Hoydoo , Cha Wonsuk , Harder Ross , Mariano Ruperto , Kanan Mathew , Kawaguchi Tomoya
Published: November 2022

Deeply penetrating X-rays are well suited to investigate the electrochemical systems and interfaces under in-situ / operando environments. In particular, a recently developed X-ray Bragg Coherent Diffractive Imaging (BCDI) is a powerful tool for 3D imaging of internal structures of nano-size particles, [1,2] and the internal compositions of alloy nanoparticles. [3-5] Further, the well-annealed alloy nanoparticles can be electrochemical treated to increase the surface strain and to enhance the certain electrocatalytic activities such as oxygen reduction reaction (ORR). [6] After introduction of the technique and examples, we will focus on how strain in a single Pt nano-grain evolves in response to applied potential. The strain responses then will be discussed within the context of surface oxidation and oxygen-evolution reaction (OER).

For Pt nanograins of a film grown on a substrate, the strain response is tightly related to the place-exchange surface oxidation and electrochemical double layer to the applied potential range relevant to OER. During polarization, marked changes in surface strain arise from the Coulombic attraction between the electrode surface and electrolyte ions, while the strain in the bulk of the crystal remained unchanged. The concurrent surface redox reactions have a strong influence on the magnitude and nature of the strain dynamics under polarization.

In careful BCDI analyses, we found that only the top 10 nm of Pt at the grain/electrolyte interface responded sensitively to applied potential, while a much more muted response was observed for the remainder of the bulk Pt grain. The potential-dependent strain responses were not present at grain boundaries locked to the neighbor grains and at the bottom interface in contact to the substrate, neither of which were exposed to electrolyte. Our measurements further suggested that even highly stable electrodes such as Pt are subject to irreversible structural changes during polarization, highlighting the importance of in-situ/operando techniques to draw faithful structure-activity relationships in electrochemistry. These observations were possible due to the high strain sensitivity of BCDI combined with the near-zero X-ray scattering background of the submicron scale nanopipette electrochemical cell.

[1] Y. Liu et al., Nano Letters 17, 1595 (2017).

[2] W. Cha, Y. Liu, H. You, G. B. Stephenson, and A. Ulvestad, Advanced Functional Materials 27, 1700331 (2017).

[3] T. Kawaguchi et al., Physical Review Letters 123, 246001 (2019).

[4] T. Kawaguchi, W. Cha, V. Latyshev, S. Vorobiov, V. Komanicky, and H. You, Journal of the Korean Physical Society 75, 528 (2019).

[5] S. Choi et al., Nano Letters 20, 8541 (2020).

[6] T. Kawaguchi, V. Komanicky, V. Latyshev, W. Cha, E. R. Maxey, R. Harder, T. Ichitsubo, and H. You, Nano Letters 21, 5945 (2021).
Effect of Covalent Modification on Proton-Coupled Electron Transfer at Quinone-Functionalized Carbon Electrodes
Authors: Owhoso Fiki V , Kwabi David G.
Published: November 2022

Electrodes functionalized with molecularly well-defined reactive/catalytic species have become attractive for promoting a wide variety of electrochemical energy conversion processes or systems, such as electrocatalytic CO2 and O2 reduction, as well as metal-sulfur and redox-flow batteries.1-3 Critical to the performance of these electrodes is the interaction between the electric field, and the molecular species at the electrical double layer. Nevertheless, elucidating the potential/electric field experienced at the functionalized interface is challenging. We show in this work that the acid-base thermochemical (i.e. Pourbaix) behavior of molecular quinones can vary depending on their mode of covalent attachment to a carbon electrode and ionic strength of the electrolyte, in a manner that sheds light on the experienced interfacial electric field. This work can inform strategies for effective pH modulation at electrified interfaces in ways that can enhance the electrocatalytic processes and systems mentioned above, and enable newer applications such as pH-swing-based electrochemical CO2 capture using appropriately chemically modified electrodes.4

References

1 Ren, G. et al. Porous Core–Shell Fe3C Embedded N-doped Carbon Nanofibers as an Effective Electrocatalysts for Oxygen Reduction Reaction. ACS Applied Materials & Interfaces
8, 4118-4125, doi:10.1021/acsami.5b11786 (2016).

2 Zhang, S., Fan, Q., Xia, R. & Meyer, T. J. CO2 Reduction: From Homogeneous to Heterogeneous Electrocatalysis. Accounts of Chemical Research
53, 255-264, doi:10.1021/acs.accounts.9b00496 (2020).

3 Zhao, C.-X. et al. Semi-Immobilized Molecular Electrocatalysts for High-Performance Lithium–Sulfur Batteries. Journal of the American Chemical Society
143, 19865-19872, doi:10.1021/jacs.1c09107 (2021).

4 Jin, S., Wu, M., Gordon, R. G., Aziz, M. J. & Kwabi, D. G. pH swing cycle for CO2 capture electrochemically driven through proton-coupled electron transfer. Energy & Environmental Science, doi:10.1039/D0EE01834A (2020).
(Invited) Potassium (co)Intercalation in Graphite: How Electrolyte Concentration May Trigger Different Cation Insertion Mechanisms
Authors: Le Pham Phuong Nam , Gabaudan Vincent , Boulaoued Athmane , Avall Gustav , Monconduit Laure , Johansson Patrik , Stievano Lorenzo
Published: November 2022

Recently, potassium-ion batteries (KIB) have been considered as a potential alternative of Li-ion batteries due to the cost effectiveness and the variety of electrode materials. Graphite – the well-known anode in LIB – has gained numerous attention from KIB scientists owing to its ability of intercalating K+ ion to form KC8 with high theoretical capacity (278 mAh/g) and good cycling retention.

KFSI in DME has been considered as a promising electrolyte for KIB due to its compatibility with not only K metal but also the electrode materials. However, the electrolyte concentration strongly affects the electrochemistry of graphite. A change in the intercalating species as increasing the salt concentration, going from the cointercalation of [K(DME)x]+ (observed at 1M) to the simple intercalation of bare K+ ions (at 5M), was confirmed by galvanostatic profiles and operando XRD.

By a complementary theoretical-experimental approach combining Raman spectroscopy with quantum chemistry, we provide here an insightful and coherent explanation of the occurring of the two different mechanisms, showing that they depend upon the solvation of K+ ions in DME rather than on the different SEI formed, as usually observed in lithium batteries.

In some specific conditions, it was also possible to observe the co-existence of the two mechanisms, with the partial formation of staged intercalated-cointercalated layers, proving without doubt that the nature of the solvated species can be a major driving force driving specific ion insertion mechanisms.
(Invited) Degradation Processes at the Potassium Hexacyanoferrate Electrode in Potassium-Ion Batteries
Authors: Khudyshkina Anna D. , Panasenko Iurii , Henkel Philip , Njel Christian , Jeschull Fabian
Published: November 2022

Prussian blue analogues (PBAs)[1] with the general composition A2M[Fe(CN)6] (A: alkali metal; M: Fe, Mn, etc) are an attractive positive electrode for potassium-ion batteries, owing to their chemical composition based on widely abundant materials, ease of synthesis, high electrochemical reversibility and higher average potential compared to its sodium congener [1]. The combination of a PBA electrode with a graphite negative electrode in a full cell configuration showed great promise as post-Li battery system. However, the upper cut-off potentials of K2Fe[Fe(CN)6] and K2Mn[Fe(CN)6] pose serious stability issues with respect to irreversible electrolyte degradation reactions. In addition, the electrolyte components have to be compatible with the potassium intercalation reaction at the graphite electrode[2], thus limiting the number of suitable electrolyte constituents.

In this presentation, we discuss aspects of the material synthesis and electrolyte degradation processes at high potentials in liquid carbonate-based electrolytes. As we will be shown the choice of the precursors is paramount to arrive at suitable particle sizes and has a great impact on the electrochemical behavior of the material. Likewise, the density of Fe-vacancies strongly depends on the chosen synthesis and may lead to significant losses in the achievable discharge capacity.

The electrode-electrolyte interface in half and full cell configurations was studied by in-house and synchrotron-based photoelectron spectroscopy (PES) for a detailed characterization of the surface layer and the oxidation states of iron in K2Fe[Fe(CN)6] electrodes. This combined analysis of electrochemical and surface-sensitive analytical studies provides a general picture of the electrode degradation at high potentials and fosters the development of better electrolyte mixtures. Our results further show, how a deliberate choice of electrolyte components can help to reduce irreversible reactions and improve cycling stability and cycle life of potassium-ion batteries. For this we have recently expanded our activities also to solid polymer electrolytes, showing superior capacity retention to liquid electrolyte systems[3].

Figure 1. left: K2Fe[Fe(CN)6] obtained using different Fe-precursors; right: capacity retention of PBA-K cells cycled in either a liquid (black) or solid polymer (red/purple) electrolyte.

Reference
s
:

[1] Kim et al., Trends Chem. 1 (2019) 682–692.

[2] Allgayer et al., ACS Appl. Energy Mater. 5 (2022) 1136–1148.

[3] Khudyshkina et al., ACS Appl. Polym. Mater. 4 (2022) 2734–2746.

Figure 1
(Digital Presentation) Electrochemistry and Structural Study of Manganese Hexacyanoferrate Cathode Material in Aqueous Zn-Ion Battery
Authors: Li Min , Sciacca Rosalinda , Maisuradze Mariam , Aquilanti Giuliana , Plaisier Jasper Rikkert , Berrettoni Mario , Giorgetti Marco
Published: November 2022

Aqueous rechargeable Zinc-ion batteries (ARZIBs) have attracted extensive attention as one of the most promising post-lithium ion battery candidates for large-scale electrochemical applications, because of their low cost, intrinsic safety, and environmental friendliness. The metallic zinc, as an ideal anode material shows high theoretical gravimetric and volumetric capacity of 820 mAh g-1 and 5855 mAh cm-3, low electrochemical potential (-0.76 V vs. SHE) and high abundance.[1,2]

Manganese hexacyanoferrate (MnHCF), one of the Prussian blue analogues (PBAs), has attracted widely attention as promising cathode material for Li-ion and post-Li ion batteries. MnHCF is composed of only highly abundant metals and displays large capacity and high discharge potential owning to the two-redox active sites [3-4]. Here, the electrochemical performance of MnHCF was studied in 3 M ZnSO4 aqueous electrolyte with Zn sheet as anode. The battery exhibits high specific capacity (176 mAhg-1) at C/20, and around 61% capacity retention after 50 cycles at C/5. In order to explain the capacity fading problems during cycling, the local geometric, electronic structures, as well as the framework structure change of MnHCF electrode were studied by means of ex-situ X-ray absorption spectroscopy (XAS) and synchrotron X-ray diffraction (XRD). Based on XAS data, no obvious change was observed at the Fe K-edge during cycling, and this indicates that there is no apparent change of the local Fe structural environment. However, the XAS spectra of Mn K-edge exhibit an apparent change after 10 cycles. The Zn K-edge shows a typical -Zn-NC-Fe- structural framework in the cycled samples that resembles the one of zinc hexacyanoferrate (ZnHCF), providing evidence for Zn-Mn partially replacement upon cycling, resulting in dissolution the Mn ion [5]. From the ex-situ XRD data, we found that this phase changes mainly concerns early cycles, because the XRD patterns of the 2nd and 10th cycle are almost identical. ZnHCF phase formed even during the first charge process. The more detailed phase transformation process is still under studying. By combing the ex-situ XAS and XRD data, the charge/discharge mechanism of MnHCF in aqueous Zn-ion battery can be more clearly illustrated.

Trócoli, F. La Mantia, ChemSusChem. 8, 2015, 481–485.

Tang, L. Shan, S. Liang, J. Zhou, Energy Environ. Sci. 12, 2019, 3288–3304.

Mullaliu, J. Asenbauer, G. Aquilanti, S. Passerini, M. Giorgetti. Small Methods, 2019, 1900529.

Mullaliu, M. Gaboardi, J. R. Plaisier, S. Passerini, and M. Giorgetti, ACS Applied Energy Materials 3, 2020, 5728.

Li, R. Sciacca, M. Maisuradze, G. Aquilanti, J. Plaisier, M. Berrettoni, M. Giorgetti, Electrochim. Acta. 400 ,2021.
The Adsorption of Bipyridine on Single-Crystal Electrodes from an Ionic Liquid Electrolyte
Authors: Ers Heigo , Siinor Liis , Lust Enn , Pikma Piret
Published: November 2022

The self-assembly of adsorbed molecules into structured adlayers on the electrode’s surface provides a straightforward way to modify the interface. Moreover, the formation and properties of the formed adlayers can be controlled by the applied potential, which offers fascinating prospects for the development of molecular switches1, thin film transistors2, and sensors3. Ionic liquids are a class of unique electrolytes, which properties differ notably from common aqueous or organic electrolytes. For example, due to good electrochemical stability and low vapour pressure of ionic liquids4, the adlayer formation process can be studied and the interfacial properties tuned in a significantly larger potential range.

In the given presentation, we will focus on the adsorption of 4,4’-bipyridine (4,4’-BP) on single-crystal model electrodes from ionic liquid electrolyte. To gain insight into the process and formed structures, we have combined electrochemical impedance spectroscopy and in situ scanning tunnelling microscopy measurements with density functional theory calculations. The results show the formation of two distinct 4,4’-BP adlayers on the Sb(111) electrode on top of each other, visualized thanks to the occurrence of partial reductive desorption of 4,4’-BP5. In the case of the Cd(0001) surface, a similar reduction process was visible in the cyclic voltammetry and capacitance, potential dependences, although the formed 4,4’-BP adlayers were not visible with the in situ STM.

Acknowledgments:

This work was supported by the Estonian Research Council grant PSG249, and by the EU through the European Regional Development Fund under project TK141 (2014-2020.4.01.15-0011).

References:

Yasini, P. et al. Potential-Induced High-Conductance Transport Pathways through Single-Molecule Junctions. J. Am. Chem. Soc
141, 10109–10116 (2019).

Casalini, S., Bortolotti, C. A., Leonardi, F. & Biscarini, F. Self-assembled monolayers in organic electronics. Chem. Soc. Rev.
46, 40–71 (2017).

Singh, M., Kaur, N. & Comini, E. The role of self-assembled monolayers in electronic devices. J. Mater. Chem. C
8, 3938–3955 (2020).

Galiński, M., Lewandowski, A. & Stepniak, I. Ionic liquids as electrolytes. Electrochim. Acta
51, 5567–5580 (2006).

Ers, H., Siinor, L., Siimenson, C., Lust, E. & Pikma, P. Order beyond a monolayer: The story of two self-assembled 4,4′-bipyridine layers on the Sb(111) | ionic liquid interface. Electrochim. Acta
421, 140468 (2022).